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FAILED: patch "[PATCH] crypto: powerpc/poly1305 - add depends on BROKEN for now" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x bc8169003b41e89fe7052e408cf9fdbecb4017fe # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062040-daylight-scrubber-8837@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From bc8169003b41e89fe7052e408cf9fdbecb4017fe Mon Sep 17 00:00:00 2001 From: Eric Biggers <ebiggers(a)google.com> Date: Tue, 20 May 2025 10:39:29 +0800 Subject: [PATCH] crypto: powerpc/poly1305 - add depends on BROKEN for now As discussed in the thread containing https://lore.kernel.org/linux-crypto/20250510053308.GB505731@sol/, the Power10-optimized Poly1305 code is currently not safe to call in softirq context. Disable it for now. It can be re-enabled once it is fixed. Fixes: ba8f8624fde2 ("crypto: poly1305-p10 - Glue code for optmized Poly1305 implementation for ppc64le") Cc: stable(a)vger.kernel.org Signed-off-by: Eric Biggers <ebiggers(a)google.com> Signed-off-by: Herbert Xu <herbert(a)gondor.apana.org.au> diff --git a/arch/powerpc/lib/crypto/Kconfig b/arch/powerpc/lib/crypto/Kconfig index ffa541ad6d5d..3f9e1bbd9905 100644 --- a/arch/powerpc/lib/crypto/Kconfig +++ b/arch/powerpc/lib/crypto/Kconfig @@ -10,6 +10,7 @@ config CRYPTO_CHACHA20_P10 config CRYPTO_POLY1305_P10 tristate depends on PPC64 && CPU_LITTLE_ENDIAN && VSX + depends on BROKEN # Needs to be fixed to work in softirq context default CRYPTO_LIB_POLY1305 select CRYPTO_ARCH_HAVE_LIB_POLY1305 select CRYPTO_LIB_POLY1305_GENERIC

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FAILED: patch "[PATCH] crypto: powerpc/poly1305 - add depends on BROKEN for now" failed to apply to 6.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.15.y git checkout FETCH_HEAD git cherry-pick -x bc8169003b41e89fe7052e408cf9fdbecb4017fe # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062040-slinging-salvaging-1638@gregkh' --subject-prefix 'PATCH 6.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From bc8169003b41e89fe7052e408cf9fdbecb4017fe Mon Sep 17 00:00:00 2001 From: Eric Biggers <ebiggers(a)google.com> Date: Tue, 20 May 2025 10:39:29 +0800 Subject: [PATCH] crypto: powerpc/poly1305 - add depends on BROKEN for now As discussed in the thread containing https://lore.kernel.org/linux-crypto/20250510053308.GB505731@sol/, the Power10-optimized Poly1305 code is currently not safe to call in softirq context. Disable it for now. It can be re-enabled once it is fixed. Fixes: ba8f8624fde2 ("crypto: poly1305-p10 - Glue code for optmized Poly1305 implementation for ppc64le") Cc: stable(a)vger.kernel.org Signed-off-by: Eric Biggers <ebiggers(a)google.com> Signed-off-by: Herbert Xu <herbert(a)gondor.apana.org.au> diff --git a/arch/powerpc/lib/crypto/Kconfig b/arch/powerpc/lib/crypto/Kconfig index ffa541ad6d5d..3f9e1bbd9905 100644 --- a/arch/powerpc/lib/crypto/Kconfig +++ b/arch/powerpc/lib/crypto/Kconfig @@ -10,6 +10,7 @@ config CRYPTO_CHACHA20_P10 config CRYPTO_POLY1305_P10 tristate depends on PPC64 && CPU_LITTLE_ENDIAN && VSX + depends on BROKEN # Needs to be fixed to work in softirq context default CRYPTO_LIB_POLY1305 select CRYPTO_ARCH_HAVE_LIB_POLY1305 select CRYPTO_LIB_POLY1305_GENERIC

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FAILED: patch "[PATCH] crypto: powerpc/poly1305 - add depends on BROKEN for now" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x bc8169003b41e89fe7052e408cf9fdbecb4017fe # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062040-renderer-tremor-6a52@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From bc8169003b41e89fe7052e408cf9fdbecb4017fe Mon Sep 17 00:00:00 2001 From: Eric Biggers <ebiggers(a)google.com> Date: Tue, 20 May 2025 10:39:29 +0800 Subject: [PATCH] crypto: powerpc/poly1305 - add depends on BROKEN for now As discussed in the thread containing https://lore.kernel.org/linux-crypto/20250510053308.GB505731@sol/, the Power10-optimized Poly1305 code is currently not safe to call in softirq context. Disable it for now. It can be re-enabled once it is fixed. Fixes: ba8f8624fde2 ("crypto: poly1305-p10 - Glue code for optmized Poly1305 implementation for ppc64le") Cc: stable(a)vger.kernel.org Signed-off-by: Eric Biggers <ebiggers(a)google.com> Signed-off-by: Herbert Xu <herbert(a)gondor.apana.org.au> diff --git a/arch/powerpc/lib/crypto/Kconfig b/arch/powerpc/lib/crypto/Kconfig index ffa541ad6d5d..3f9e1bbd9905 100644 --- a/arch/powerpc/lib/crypto/Kconfig +++ b/arch/powerpc/lib/crypto/Kconfig @@ -10,6 +10,7 @@ config CRYPTO_CHACHA20_P10 config CRYPTO_POLY1305_P10 tristate depends on PPC64 && CPU_LITTLE_ENDIAN && VSX + depends on BROKEN # Needs to be fixed to work in softirq context default CRYPTO_LIB_POLY1305 select CRYPTO_ARCH_HAVE_LIB_POLY1305 select CRYPTO_LIB_POLY1305_GENERIC

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FAILED: patch "[PATCH] crypto: marvell/cesa - Do not chain submitted requests" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 0413bcf0fc460a68a2a7a8354aee833293d7d693 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062023-fidgety-landslide-5061@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 0413bcf0fc460a68a2a7a8354aee833293d7d693 Mon Sep 17 00:00:00 2001 From: Herbert Xu <herbert(a)gondor.apana.org.au> Date: Thu, 8 May 2025 13:22:16 +0800 Subject: [PATCH] crypto: marvell/cesa - Do not chain submitted requests This driver tries to chain requests together before submitting them to hardware in order to reduce completion interrupts. However, it even extends chains that have already been submitted to hardware. This is dangerous because there is no way of knowing whether the hardware has already read the DMA memory in question or not. Fix this by splitting the chain list into two. One for submitted requests and one for requests that have not yet been submitted. Only extend the latter. Reported-by: Klaus Kudielka <klaus.kudielka(a)gmail.com> Fixes: 85030c5168f1 ("crypto: marvell - Add support for chaining crypto requests in TDMA mode") Cc: <stable(a)vger.kernel.org> Signed-off-by: Herbert Xu <herbert(a)gondor.apana.org.au> diff --git a/drivers/crypto/marvell/cesa/cesa.c b/drivers/crypto/marvell/cesa/cesa.c index fa08f10e6f3f..9c21f5d835d2 100644 --- a/drivers/crypto/marvell/cesa/cesa.c +++ b/drivers/crypto/marvell/cesa/cesa.c @@ -94,7 +94,7 @@ static int mv_cesa_std_process(struct mv_cesa_engine *engine, u32 status) static int mv_cesa_int_process(struct mv_cesa_engine *engine, u32 status) { - if (engine->chain.first && engine->chain.last) + if (engine->chain_hw.first && engine->chain_hw.last) return mv_cesa_tdma_process(engine, status); return mv_cesa_std_process(engine, status); diff --git a/drivers/crypto/marvell/cesa/cesa.h b/drivers/crypto/marvell/cesa/cesa.h index d215a6bed6bc..50ca1039fdaa 100644 --- a/drivers/crypto/marvell/cesa/cesa.h +++ b/drivers/crypto/marvell/cesa/cesa.h @@ -440,8 +440,10 @@ struct mv_cesa_dev { * SRAM * @queue: fifo of the pending crypto requests * @load: engine load counter, useful for load balancing - * @chain: list of the current tdma descriptors being processed - * by this engine. + * @chain_hw: list of the current tdma descriptors being processed + * by the hardware. + * @chain_sw: list of the current tdma descriptors that will be + * submitted to the hardware. * @complete_queue: fifo of the processed requests by the engine * * Structure storing CESA engine information. @@ -463,7 +465,8 @@ struct mv_cesa_engine { struct gen_pool *pool; struct crypto_queue queue; atomic_t load; - struct mv_cesa_tdma_chain chain; + struct mv_cesa_tdma_chain chain_hw; + struct mv_cesa_tdma_chain chain_sw; struct list_head complete_queue; int irq; }; diff --git a/drivers/crypto/marvell/cesa/tdma.c b/drivers/crypto/marvell/cesa/tdma.c index 388a06e180d6..243305354420 100644 --- a/drivers/crypto/marvell/cesa/tdma.c +++ b/drivers/crypto/marvell/cesa/tdma.c @@ -38,6 +38,15 @@ void mv_cesa_dma_step(struct mv_cesa_req *dreq) { struct mv_cesa_engine *engine = dreq->engine; + spin_lock_bh(&engine->lock); + if (engine->chain_sw.first == dreq->chain.first) { + engine->chain_sw.first = NULL; + engine->chain_sw.last = NULL; + } + engine->chain_hw.first = dreq->chain.first; + engine->chain_hw.last = dreq->chain.last; + spin_unlock_bh(&engine->lock); + writel_relaxed(0, engine->regs + CESA_SA_CFG); mv_cesa_set_int_mask(engine, CESA_SA_INT_ACC0_IDMA_DONE); @@ -96,25 +105,27 @@ void mv_cesa_dma_prepare(struct mv_cesa_req *dreq, void mv_cesa_tdma_chain(struct mv_cesa_engine *engine, struct mv_cesa_req *dreq) { - if (engine->chain.first == NULL && engine->chain.last == NULL) { - engine->chain.first = dreq->chain.first; - engine->chain.last = dreq->chain.last; - } else { - struct mv_cesa_tdma_desc *last; + struct mv_cesa_tdma_desc *last = engine->chain_sw.last; - last = engine->chain.last; + /* + * Break the DMA chain if the request being queued needs the IV + * regs to be set before lauching the request. + */ + if (!last || dreq->chain.first->flags & CESA_TDMA_SET_STATE) + engine->chain_sw.first = dreq->chain.first; + else { last->next = dreq->chain.first; - engine->chain.last = dreq->chain.last; - - /* - * Break the DMA chain if the CESA_TDMA_BREAK_CHAIN is set on - * the last element of the current chain, or if the request - * being queued needs the IV regs to be set before lauching - * the request. - */ - if (!(last->flags & CESA_TDMA_BREAK_CHAIN) && - !(dreq->chain.first->flags & CESA_TDMA_SET_STATE)) - last->next_dma = cpu_to_le32(dreq->chain.first->cur_dma); + last->next_dma = cpu_to_le32(dreq->chain.first->cur_dma); + } + last = dreq->chain.last; + engine->chain_sw.last = last; + /* + * Break the DMA chain if the CESA_TDMA_BREAK_CHAIN is set on + * the last element of the current chain. + */ + if (last->flags & CESA_TDMA_BREAK_CHAIN) { + engine->chain_sw.first = NULL; + engine->chain_sw.last = NULL; } } @@ -127,7 +138,7 @@ int mv_cesa_tdma_process(struct mv_cesa_engine *engine, u32 status) tdma_cur = readl(engine->regs + CESA_TDMA_CUR); - for (tdma = engine->chain.first; tdma; tdma = next) { + for (tdma = engine->chain_hw.first; tdma; tdma = next) { spin_lock_bh(&engine->lock); next = tdma->next; spin_unlock_bh(&engine->lock); @@ -149,12 +160,12 @@ int mv_cesa_tdma_process(struct mv_cesa_engine *engine, u32 status) &backlog); /* Re-chaining to the next request */ - engine->chain.first = tdma->next; + engine->chain_hw.first = tdma->next; tdma->next = NULL; /* If this is the last request, clear the chain */ - if (engine->chain.first == NULL) - engine->chain.last = NULL; + if (engine->chain_hw.first == NULL) + engine->chain_hw.last = NULL; spin_unlock_bh(&engine->lock); ctx = crypto_tfm_ctx(req->tfm);

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[merged mm-hotfixes-stable] maple_tree-fix-ma_state_prealloc-flag-in-mas_preallocate.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: maple_tree: fix MA_STATE_PREALLOC flag in mas_preallocate() has been removed from the -mm tree. Its filename was maple_tree-fix-ma_state_prealloc-flag-in-mas_preallocate.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: "Liam R. Howlett" <Liam.Howlett(a)oracle.com> Subject: maple_tree: fix MA_STATE_PREALLOC flag in mas_preallocate() Date: Mon, 16 Jun 2025 14:45:20 -0400 Temporarily clear the preallocation flag when explicitly requesting allocations. Pre-existing allocations are already counted against the request through mas_node_count_gfp(), but the allocations will not happen if the MA_STATE_PREALLOC flag is set. This flag is meant to avoid re-allocating in bulk allocation mode, and to detect issues with preallocation calculations. The MA_STATE_PREALLOC flag should also always be set on zero allocations so that detection of underflow allocations will print a WARN_ON() during consumption. User visible effect of this flaw is a WARN_ON() followed by a null pointer dereference when subsequent requests for larger number of nodes is ignored, such as the vma merge retry in mmap_region() caused by drivers altering the vma flags (which happens in v6.6, at least) Link: https://lkml.kernel.org/r/20250616184521.3382795-3-Liam.Howlett@oracle.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. Howlett <Liam.Howlett(a)oracle.com> Reported-by: Zhaoyang Huang <zhaoyang.huang(a)unisoc.com> Reported-by: Hailong Liu <hailong.liu(a)oppo.com> Link: https://lore.kernel.org/all/1652f7eb-a51b-4fee-8058-c73af63bacd1@oppo.com/ Link: https://lore.kernel.org/all/20250428184058.1416274-1-Liam.Howlett@oracle.co… Link: https://lore.kernel.org/all/20250429014754.1479118-1-Liam.Howlett@oracle.co… Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Suren Baghdasaryan <surenb(a)google.com> Cc: Hailong Liu <hailong.liu(a)oppo.com> Cc: zhangpeng.00(a)bytedance.com <zhangpeng.00(a)bytedance.com> Cc: Steve Kang <Steve.Kang(a)unisoc.com> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: Sidhartha Kumar <sidhartha.kumar(a)oracle.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- lib/maple_tree.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/lib/maple_tree.c~maple_tree-fix-ma_state_prealloc-flag-in-mas_preallocate +++ a/lib/maple_tree.c @@ -5527,8 +5527,9 @@ int mas_preallocate(struct ma_state *mas mas->store_type = mas_wr_store_type(&wr_mas); request = mas_prealloc_calc(&wr_mas, entry); if (!request) - return ret; + goto set_flag; + mas->mas_flags &= ~MA_STATE_PREALLOC; mas_node_count_gfp(mas, request, gfp); if (mas_is_err(mas)) { mas_set_alloc_req(mas, 0); @@ -5538,6 +5539,7 @@ int mas_preallocate(struct ma_state *mas return ret; } +set_flag: mas->mas_flags |= MA_STATE_PREALLOC; return ret; } _ Patches currently in -mm which might be from Liam.Howlett(a)oracle.com are tools-testing-radix-tree-test-maple-tree-chaining-mas_preallocate-calls.patch

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[merged mm-hotfixes-stable] bcache-remove-unnecessary-select-min_heap.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: bcache: remove unnecessary select MIN_HEAP has been removed from the -mm tree. Its filename was bcache-remove-unnecessary-select-min_heap.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Kuan-Wei Chiu <visitorckw(a)gmail.com> Subject: bcache: remove unnecessary select MIN_HEAP Date: Sun, 15 Jun 2025 04:23:53 +0800 After reverting the transition to the generic min heap library, bcache no longer depends on MIN_HEAP. The select entry can be removed to reduce code size and shrink the kernel's attack surface. This change effectively reverts the bcache-related part of commit 92a8b224b833 ("lib/min_heap: introduce non-inline versions of min heap API functions"). This is part of a series of changes to address a performance regression caused by the use of the generic min_heap implementation. As reported by Robert, bcache now suffers from latency spikes, with P100 (max) latency increasing from 600 ms to 2.4 seconds every 5 minutes. These regressions degrade bcache's effectiveness as a low-latency cache layer and lead to frequent timeouts and application stalls in production environments. Link: https://lore.kernel.org/lkml/CAJhEC05+0S69z+3+FB2Cd0hD+pCRyWTKLEOsc8BOmH73p… Link: https://lkml.kernel.org/r/20250614202353.1632957-4-visitorckw@gmail.com Fixes: 866898efbb25 ("bcache: remove heap-related macros and switch to generic min_heap") Fixes: 92a8b224b833 ("lib/min_heap: introduce non-inline versions of min heap API functions") Signed-off-by: Kuan-Wei Chiu <visitorckw(a)gmail.com> Reported-by: Robert Pang <robertpang(a)google.com> Closes: https://lore.kernel.org/linux-bcache/CAJhEC06F_AtrPgw2-7CvCqZgeStgCtitbD-ry… Acked-by: Coly Li <colyli(a)kernel.org> Cc: Ching-Chun (Jim) Huang <jserv(a)ccns.ncku.edu.tw> Cc: Kent Overstreet <kent.overstreet(a)linux.dev> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- drivers/md/bcache/Kconfig | 1 - 1 file changed, 1 deletion(-) --- a/drivers/md/bcache/Kconfig~bcache-remove-unnecessary-select-min_heap +++ a/drivers/md/bcache/Kconfig @@ -5,7 +5,6 @@ config BCACHE select BLOCK_HOLDER_DEPRECATED if SYSFS select CRC64 select CLOSURES - select MIN_HEAP help Allows a block device to be used as cache for other devices; uses a btree for indexing and the layout is optimized for SSDs. _ Patches currently in -mm which might be from visitorckw(a)gmail.com are lib-math-gcd-use-static-key-to-select-implementation-at-runtime.patch riscv-optimize-gcd-code-size-when-config_riscv_isa_zbb-is-disabled.patch riscv-optimize-gcd-performance-on-risc-v-without-zbb-extension.patch

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[merged mm-hotfixes-stable] revert-bcache-remove-heap-related-macros-and-switch-to-generic-min_heap.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: Revert "bcache: remove heap-related macros and switch to generic min_heap" has been removed from the -mm tree. Its filename was revert-bcache-remove-heap-related-macros-and-switch-to-generic-min_heap.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Kuan-Wei Chiu <visitorckw(a)gmail.com> Subject: Revert "bcache: remove heap-related macros and switch to generic min_heap" Date: Sun, 15 Jun 2025 04:23:52 +0800 This reverts commit 866898efbb25bb44fd42848318e46db9e785973a. The generic bottom-up min_heap implementation causes performance regression in invalidate_buckets_lru(), a hot path in bcache. Before the cache is fully populated, new_bucket_prio() often returns zero, leading to many equal comparisons. In such cases, bottom-up sift_down performs up to 2 * log2(n) comparisons, while the original top-down approach completes with just O() comparisons, resulting in a measurable performance gap. The performance degradation is further worsened by the non-inlined min_heap API functions introduced in commit 92a8b224b833 ("lib/min_heap: introduce non-inline versions of min heap API functions"), adding function call overhead to this critical path. As reported by Robert, bcache now suffers from latency spikes, with P100 (max) latency increasing from 600 ms to 2.4 seconds every 5 minutes. These regressions degrade bcache's effectiveness as a low-latency cache layer and lead to frequent timeouts and application stalls in production environments. This revert aims to restore bcache's original low-latency behavior. Link: https://lore.kernel.org/lkml/CAJhEC05+0S69z+3+FB2Cd0hD+pCRyWTKLEOsc8BOmH73p… Link: https://lkml.kernel.org/r/20250614202353.1632957-3-visitorckw@gmail.com Fixes: 866898efbb25 ("bcache: remove heap-related macros and switch to generic min_heap") Fixes: 92a8b224b833 ("lib/min_heap: introduce non-inline versions of min heap API functions") Signed-off-by: Kuan-Wei Chiu <visitorckw(a)gmail.com> Reported-by: Robert Pang <robertpang(a)google.com> Closes: https://lore.kernel.org/linux-bcache/CAJhEC06F_AtrPgw2-7CvCqZgeStgCtitbD-ry… Acked-by: Coly Li <colyli(a)kernel.org> Cc: Ching-Chun (Jim) Huang <jserv(a)ccns.ncku.edu.tw> Cc: Kent Overstreet <kent.overstreet(a)linux.dev> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- drivers/md/bcache/alloc.c | 64 ++++------------ drivers/md/bcache/bcache.h | 2 drivers/md/bcache/bset.c | 124 +++++++++++--------------------- drivers/md/bcache/bset.h | 42 ++++++---- drivers/md/bcache/btree.c | 69 +++++++---------- drivers/md/bcache/extents.c | 51 ++++--------- drivers/md/bcache/movinggc.c | 41 ++-------- drivers/md/bcache/super.c | 3 drivers/md/bcache/sysfs.c | 4 - drivers/md/bcache/util.h | 67 ++++++++++++++++- drivers/md/bcache/writeback.c | 13 +-- 11 files changed, 217 insertions(+), 263 deletions(-) --- a/drivers/md/bcache/alloc.c~revert-bcache-remove-heap-related-macros-and-switch-to-generic-min_heap +++ a/drivers/md/bcache/alloc.c @@ -164,68 +164,40 @@ static void bch_invalidate_one_bucket(st * prio is worth 1/8th of what INITIAL_PRIO is worth. */ -static inline unsigned int new_bucket_prio(struct cache *ca, struct bucket *b) -{ - unsigned int min_prio = (INITIAL_PRIO - ca->set->min_prio) / 8; - - return (b->prio - ca->set->min_prio + min_prio) * GC_SECTORS_USED(b); -} - -static inline bool new_bucket_max_cmp(const void *l, const void *r, void *args) -{ - struct bucket **lhs = (struct bucket **)l; - struct bucket **rhs = (struct bucket **)r; - struct cache *ca = args; - - return new_bucket_prio(ca, *lhs) > new_bucket_prio(ca, *rhs); -} - -static inline bool new_bucket_min_cmp(const void *l, const void *r, void *args) -{ - struct bucket **lhs = (struct bucket **)l; - struct bucket **rhs = (struct bucket **)r; - struct cache *ca = args; - - return new_bucket_prio(ca, *lhs) < new_bucket_prio(ca, *rhs); -} - -static inline void new_bucket_swap(void *l, void *r, void __always_unused *args) -{ - struct bucket **lhs = l, **rhs = r; +#define bucket_prio(b) \ +({ \ + unsigned int min_prio = (INITIAL_PRIO - ca->set->min_prio) / 8; \ + \ + (b->prio - ca->set->min_prio + min_prio) * GC_SECTORS_USED(b); \ +}) - swap(*lhs, *rhs); -} +#define bucket_max_cmp(l, r) (bucket_prio(l) < bucket_prio(r)) +#define bucket_min_cmp(l, r) (bucket_prio(l) > bucket_prio(r)) static void invalidate_buckets_lru(struct cache *ca) { struct bucket *b; - const struct min_heap_callbacks bucket_max_cmp_callback = { - .less = new_bucket_max_cmp, - .swp = new_bucket_swap, - }; - const struct min_heap_callbacks bucket_min_cmp_callback = { - .less = new_bucket_min_cmp, - .swp = new_bucket_swap, - }; + ssize_t i; - ca->heap.nr = 0; + ca->heap.used = 0; for_each_bucket(b, ca) { if (!bch_can_invalidate_bucket(ca, b)) continue; - if (!min_heap_full(&ca->heap)) - min_heap_push(&ca->heap, &b, &bucket_max_cmp_callback, ca); - else if (!new_bucket_max_cmp(&b, min_heap_peek(&ca->heap), ca)) { + if (!heap_full(&ca->heap)) + heap_add(&ca->heap, b, bucket_max_cmp); + else if (bucket_max_cmp(b, heap_peek(&ca->heap))) { ca->heap.data[0] = b; - min_heap_sift_down(&ca->heap, 0, &bucket_max_cmp_callback, ca); + heap_sift(&ca->heap, 0, bucket_max_cmp); } } - min_heapify_all(&ca->heap, &bucket_min_cmp_callback, ca); + for (i = ca->heap.used / 2 - 1; i >= 0; --i) + heap_sift(&ca->heap, i, bucket_min_cmp); while (!fifo_full(&ca->free_inc)) { - if (!ca->heap.nr) { + if (!heap_pop(&ca->heap, b, bucket_min_cmp)) { /* * We don't want to be calling invalidate_buckets() * multiple times when it can't do anything @@ -234,8 +206,6 @@ static void invalidate_buckets_lru(struc wake_up_gc(ca->set); return; } - b = min_heap_peek(&ca->heap)[0]; - min_heap_pop(&ca->heap, &bucket_min_cmp_callback, ca); bch_invalidate_one_bucket(ca, b); } --- a/drivers/md/bcache/bcache.h~revert-bcache-remove-heap-related-macros-and-switch-to-generic-min_heap +++ a/drivers/md/bcache/bcache.h @@ -458,7 +458,7 @@ struct cache { /* Allocation stuff: */ struct bucket *buckets; - DEFINE_MIN_HEAP(struct bucket *, cache_heap) heap; + DECLARE_HEAP(struct bucket *, heap); /* * If nonzero, we know we aren't going to find any buckets to invalidate --- a/drivers/md/bcache/bset.c~revert-bcache-remove-heap-related-macros-and-switch-to-generic-min_heap +++ a/drivers/md/bcache/bset.c @@ -54,11 +54,9 @@ void bch_dump_bucket(struct btree_keys * int __bch_count_data(struct btree_keys *b) { unsigned int ret = 0; - struct btree_iter iter; + struct btree_iter_stack iter; struct bkey *k; - min_heap_init(&iter.heap, NULL, MAX_BSETS); - if (b->ops->is_extents) for_each_key(b, k, &iter) ret += KEY_SIZE(k); @@ -69,11 +67,9 @@ void __bch_check_keys(struct btree_keys { va_list args; struct bkey *k, *p = NULL; - struct btree_iter iter; + struct btree_iter_stack iter; const char *err; - min_heap_init(&iter.heap, NULL, MAX_BSETS); - for_each_key(b, k, &iter) { if (b->ops->is_extents) { err = "Keys out of order"; @@ -114,9 +110,9 @@ bug: static void bch_btree_iter_next_check(struct btree_iter *iter) { - struct bkey *k = iter->heap.data->k, *next = bkey_next(k); + struct bkey *k = iter->data->k, *next = bkey_next(k); - if (next < iter->heap.data->end && + if (next < iter->data->end && bkey_cmp(k, iter->b->ops->is_extents ? &START_KEY(next) : next) > 0) { bch_dump_bucket(iter->b); @@ -883,14 +879,12 @@ unsigned int bch_btree_insert_key(struct unsigned int status = BTREE_INSERT_STATUS_NO_INSERT; struct bset *i = bset_tree_last(b)->data; struct bkey *m, *prev = NULL; - struct btree_iter iter; + struct btree_iter_stack iter; struct bkey preceding_key_on_stack = ZERO_KEY; struct bkey *preceding_key_p = &preceding_key_on_stack; BUG_ON(b->ops->is_extents && !KEY_SIZE(k)); - min_heap_init(&iter.heap, NULL, MAX_BSETS); - /* * If k has preceding key, preceding_key_p will be set to address * of k's preceding key; otherwise preceding_key_p will be set @@ -901,9 +895,9 @@ unsigned int bch_btree_insert_key(struct else preceding_key(k, &preceding_key_p); - m = bch_btree_iter_init(b, &iter, preceding_key_p); + m = bch_btree_iter_stack_init(b, &iter, preceding_key_p); - if (b->ops->insert_fixup(b, k, &iter, replace_key)) + if (b->ops->insert_fixup(b, k, &iter.iter, replace_key)) return status; status = BTREE_INSERT_STATUS_INSERT; @@ -1083,102 +1077,79 @@ struct bkey *__bch_bset_search(struct bt /* Btree iterator */ -typedef bool (new_btree_iter_cmp_fn)(const void *, const void *, void *); - -static inline bool new_btree_iter_cmp(const void *l, const void *r, void __always_unused *args) -{ - const struct btree_iter_set *_l = l; - const struct btree_iter_set *_r = r; - - return bkey_cmp(_l->k, _r->k) <= 0; -} +typedef bool (btree_iter_cmp_fn)(struct btree_iter_set, + struct btree_iter_set); -static inline void new_btree_iter_swap(void *iter1, void *iter2, void __always_unused *args) +static inline bool btree_iter_cmp(struct btree_iter_set l, + struct btree_iter_set r) { - struct btree_iter_set *_iter1 = iter1; - struct btree_iter_set *_iter2 = iter2; - - swap(*_iter1, *_iter2); + return bkey_cmp(l.k, r.k) > 0; } static inline bool btree_iter_end(struct btree_iter *iter) { - return !iter->heap.nr; + return !iter->used; } void bch_btree_iter_push(struct btree_iter *iter, struct bkey *k, struct bkey *end) { - const struct min_heap_callbacks callbacks = { - .less = new_btree_iter_cmp, - .swp = new_btree_iter_swap, - }; - if (k != end) - BUG_ON(!min_heap_push(&iter->heap, - &((struct btree_iter_set) { k, end }), - &callbacks, - NULL)); + BUG_ON(!heap_add(iter, + ((struct btree_iter_set) { k, end }), + btree_iter_cmp)); } -static struct bkey *__bch_btree_iter_init(struct btree_keys *b, - struct btree_iter *iter, - struct bkey *search, - struct bset_tree *start) +static struct bkey *__bch_btree_iter_stack_init(struct btree_keys *b, + struct btree_iter_stack *iter, + struct bkey *search, + struct bset_tree *start) { struct bkey *ret = NULL; - iter->heap.size = ARRAY_SIZE(iter->heap.preallocated); - iter->heap.nr = 0; + iter->iter.size = ARRAY_SIZE(iter->stack_data); + iter->iter.used = 0; #ifdef CONFIG_BCACHE_DEBUG - iter->b = b; + iter->iter.b = b; #endif for (; start <= bset_tree_last(b); start++) { ret = bch_bset_search(b, start, search); - bch_btree_iter_push(iter, ret, bset_bkey_last(start->data)); + bch_btree_iter_push(&iter->iter, ret, bset_bkey_last(start->data)); } return ret; } -struct bkey *bch_btree_iter_init(struct btree_keys *b, - struct btree_iter *iter, +struct bkey *bch_btree_iter_stack_init(struct btree_keys *b, + struct btree_iter_stack *iter, struct bkey *search) { - return __bch_btree_iter_init(b, iter, search, b->set); + return __bch_btree_iter_stack_init(b, iter, search, b->set); } static inline struct bkey *__bch_btree_iter_next(struct btree_iter *iter, - new_btree_iter_cmp_fn *cmp) + btree_iter_cmp_fn *cmp) { struct btree_iter_set b __maybe_unused; struct bkey *ret = NULL; - const struct min_heap_callbacks callbacks = { - .less = cmp, - .swp = new_btree_iter_swap, - }; if (!btree_iter_end(iter)) { bch_btree_iter_next_check(iter); - ret = iter->heap.data->k; - iter->heap.data->k = bkey_next(iter->heap.data->k); + ret = iter->data->k; + iter->data->k = bkey_next(iter->data->k); - if (iter->heap.data->k > iter->heap.data->end) { + if (iter->data->k > iter->data->end) { WARN_ONCE(1, "bset was corrupt!\n"); - iter->heap.data->k = iter->heap.data->end; + iter->data->k = iter->data->end; } - if (iter->heap.data->k == iter->heap.data->end) { - if (iter->heap.nr) { - b = min_heap_peek(&iter->heap)[0]; - min_heap_pop(&iter->heap, &callbacks, NULL); - } - } + if (iter->data->k == iter->data->end) + heap_pop(iter, b, cmp); else - min_heap_sift_down(&iter->heap, 0, &callbacks, NULL); + heap_sift(iter, 0, cmp); } return ret; @@ -1186,7 +1157,7 @@ static inline struct bkey *__bch_btree_i struct bkey *bch_btree_iter_next(struct btree_iter *iter) { - return __bch_btree_iter_next(iter, new_btree_iter_cmp); + return __bch_btree_iter_next(iter, btree_iter_cmp); } @@ -1224,18 +1195,16 @@ static void btree_mergesort(struct btree struct btree_iter *iter, bool fixup, bool remove_stale) { + int i; struct bkey *k, *last = NULL; BKEY_PADDED(k) tmp; bool (*bad)(struct btree_keys *, const struct bkey *) = remove_stale ? bch_ptr_bad : bch_ptr_invalid; - const struct min_heap_callbacks callbacks = { - .less = b->ops->sort_cmp, - .swp = new_btree_iter_swap, - }; /* Heapify the iterator, using our comparison function */ - min_heapify_all(&iter->heap, &callbacks, NULL); + for (i = iter->used / 2 - 1; i >= 0; --i) + heap_sift(iter, i, b->ops->sort_cmp); while (!btree_iter_end(iter)) { if (b->ops->sort_fixup && fixup) @@ -1324,11 +1293,10 @@ void bch_btree_sort_partial(struct btree struct bset_sort_state *state) { size_t order = b->page_order, keys = 0; - struct btree_iter iter; + struct btree_iter_stack iter; int oldsize = bch_count_data(b); - min_heap_init(&iter.heap, NULL, MAX_BSETS); - __bch_btree_iter_init(b, &iter, NULL, &b->set[start]); + __bch_btree_iter_stack_init(b, &iter, NULL, &b->set[start]); if (start) { unsigned int i; @@ -1339,7 +1307,7 @@ void bch_btree_sort_partial(struct btree order = get_order(__set_bytes(b->set->data, keys)); } - __btree_sort(b, &iter, start, order, false, state); + __btree_sort(b, &iter.iter, start, order, false, state); EBUG_ON(oldsize >= 0 && bch_count_data(b) != oldsize); } @@ -1355,13 +1323,11 @@ void bch_btree_sort_into(struct btree_ke struct bset_sort_state *state) { uint64_t start_time = local_clock(); - struct btree_iter iter; - - min_heap_init(&iter.heap, NULL, MAX_BSETS); + struct btree_iter_stack iter; - bch_btree_iter_init(b, &iter, NULL); + bch_btree_iter_stack_init(b, &iter, NULL); - btree_mergesort(b, new->set->data, &iter, false, true); + btree_mergesort(b, new->set->data, &iter.iter, false, true); bch_time_stats_update(&state->time, start_time); --- a/drivers/md/bcache/bset.h~revert-bcache-remove-heap-related-macros-and-switch-to-generic-min_heap +++ a/drivers/md/bcache/bset.h @@ -187,9 +187,8 @@ struct bset_tree { }; struct btree_keys_ops { - bool (*sort_cmp)(const void *l, - const void *r, - void *args); + bool (*sort_cmp)(struct btree_iter_set l, + struct btree_iter_set r); struct bkey *(*sort_fixup)(struct btree_iter *iter, struct bkey *tmp); bool (*insert_fixup)(struct btree_keys *b, @@ -313,17 +312,23 @@ enum { BTREE_INSERT_STATUS_FRONT_MERGE, }; -struct btree_iter_set { - struct bkey *k, *end; -}; - /* Btree key iteration */ struct btree_iter { + size_t size, used; #ifdef CONFIG_BCACHE_DEBUG struct btree_keys *b; #endif - MIN_HEAP_PREALLOCATED(struct btree_iter_set, btree_iter_heap, MAX_BSETS) heap; + struct btree_iter_set { + struct bkey *k, *end; + } data[]; +}; + +/* Fixed-size btree_iter that can be allocated on the stack */ + +struct btree_iter_stack { + struct btree_iter iter; + struct btree_iter_set stack_data[MAX_BSETS]; }; typedef bool (*ptr_filter_fn)(struct btree_keys *b, const struct bkey *k); @@ -335,9 +340,9 @@ struct bkey *bch_btree_iter_next_filter( void bch_btree_iter_push(struct btree_iter *iter, struct bkey *k, struct bkey *end); -struct bkey *bch_btree_iter_init(struct btree_keys *b, - struct btree_iter *iter, - struct bkey *search); +struct bkey *bch_btree_iter_stack_init(struct btree_keys *b, + struct btree_iter_stack *iter, + struct bkey *search); struct bkey *__bch_bset_search(struct btree_keys *b, struct bset_tree *t, const struct bkey *search); @@ -352,13 +357,14 @@ static inline struct bkey *bch_bset_sear return search ? __bch_bset_search(b, t, search) : t->data->start; } -#define for_each_key_filter(b, k, iter, filter) \ - for (bch_btree_iter_init((b), (iter), NULL); \ - ((k) = bch_btree_iter_next_filter((iter), (b), filter));) - -#define for_each_key(b, k, iter) \ - for (bch_btree_iter_init((b), (iter), NULL); \ - ((k) = bch_btree_iter_next(iter));) +#define for_each_key_filter(b, k, stack_iter, filter) \ + for (bch_btree_iter_stack_init((b), (stack_iter), NULL); \ + ((k) = bch_btree_iter_next_filter(&((stack_iter)->iter), (b), \ + filter));) + +#define for_each_key(b, k, stack_iter) \ + for (bch_btree_iter_stack_init((b), (stack_iter), NULL); \ + ((k) = bch_btree_iter_next(&((stack_iter)->iter)));) /* Sorting */ --- a/drivers/md/bcache/btree.c~revert-bcache-remove-heap-related-macros-and-switch-to-generic-min_heap +++ a/drivers/md/bcache/btree.c @@ -148,19 +148,19 @@ void bch_btree_node_read_done(struct btr { const char *err = "bad btree header"; struct bset *i = btree_bset_first(b); - struct btree_iter iter; + struct btree_iter *iter; /* * c->fill_iter can allocate an iterator with more memory space * than static MAX_BSETS. * See the comment arount cache_set->fill_iter. */ - iter.heap.data = mempool_alloc(&b->c->fill_iter, GFP_NOIO); - iter.heap.size = b->c->cache->sb.bucket_size / b->c->cache->sb.block_size; - iter.heap.nr = 0; + iter = mempool_alloc(&b->c->fill_iter, GFP_NOIO); + iter->size = b->c->cache->sb.bucket_size / b->c->cache->sb.block_size; + iter->used = 0; #ifdef CONFIG_BCACHE_DEBUG - iter.b = &b->keys; + iter->b = &b->keys; #endif if (!i->seq) @@ -198,7 +198,7 @@ void bch_btree_node_read_done(struct btr if (i != b->keys.set[0].data && !i->keys) goto err; - bch_btree_iter_push(&iter, i->start, bset_bkey_last(i)); + bch_btree_iter_push(iter, i->start, bset_bkey_last(i)); b->written += set_blocks(i, block_bytes(b->c->cache)); } @@ -210,7 +210,7 @@ void bch_btree_node_read_done(struct btr if (i->seq == b->keys.set[0].data->seq) goto err; - bch_btree_sort_and_fix_extents(&b->keys, &iter, &b->c->sort); + bch_btree_sort_and_fix_extents(&b->keys, iter, &b->c->sort); i = b->keys.set[0].data; err = "short btree key"; @@ -222,7 +222,7 @@ void bch_btree_node_read_done(struct btr bch_bset_init_next(&b->keys, write_block(b), bset_magic(&b->c->cache->sb)); out: - mempool_free(iter.heap.data, &b->c->fill_iter); + mempool_free(iter, &b->c->fill_iter); return; err: set_btree_node_io_error(b); @@ -1306,11 +1306,9 @@ static bool btree_gc_mark_node(struct bt uint8_t stale = 0; unsigned int keys = 0, good_keys = 0; struct bkey *k; - struct btree_iter iter; + struct btree_iter_stack iter; struct bset_tree *t; - min_heap_init(&iter.heap, NULL, MAX_BSETS); - gc->nodes++; for_each_key_filter(&b->keys, k, &iter, bch_ptr_invalid) { @@ -1569,11 +1567,9 @@ static int btree_gc_rewrite_node(struct static unsigned int btree_gc_count_keys(struct btree *b) { struct bkey *k; - struct btree_iter iter; + struct btree_iter_stack iter; unsigned int ret = 0; - min_heap_init(&iter.heap, NULL, MAX_BSETS); - for_each_key_filter(&b->keys, k, &iter, bch_ptr_bad) ret += bkey_u64s(k); @@ -1612,18 +1608,18 @@ static int btree_gc_recurse(struct btree int ret = 0; bool should_rewrite; struct bkey *k; - struct btree_iter iter; + struct btree_iter_stack iter; struct gc_merge_info r[GC_MERGE_NODES]; struct gc_merge_info *i, *last = r + ARRAY_SIZE(r) - 1; - min_heap_init(&iter.heap, NULL, MAX_BSETS); - bch_btree_iter_init(&b->keys, &iter, &b->c->gc_done); + bch_btree_iter_stack_init(&b->keys, &iter, &b->c->gc_done); for (i = r; i < r + ARRAY_SIZE(r); i++) i->b = ERR_PTR(-EINTR); while (1) { - k = bch_btree_iter_next_filter(&iter, &b->keys, bch_ptr_bad); + k = bch_btree_iter_next_filter(&iter.iter, &b->keys, + bch_ptr_bad); if (k) { r->b = bch_btree_node_get(b->c, op, k, b->level - 1, true, b); @@ -1918,9 +1914,7 @@ static int bch_btree_check_recurse(struc { int ret = 0; struct bkey *k, *p = NULL; - struct btree_iter iter; - - min_heap_init(&iter.heap, NULL, MAX_BSETS); + struct btree_iter_stack iter; for_each_key_filter(&b->keys, k, &iter, bch_ptr_invalid) bch_initial_mark_key(b->c, b->level, k); @@ -1928,10 +1922,10 @@ static int bch_btree_check_recurse(struc bch_initial_mark_key(b->c, b->level + 1, &b->key); if (b->level) { - bch_btree_iter_init(&b->keys, &iter, NULL); + bch_btree_iter_stack_init(&b->keys, &iter, NULL); do { - k = bch_btree_iter_next_filter(&iter, &b->keys, + k = bch_btree_iter_next_filter(&iter.iter, &b->keys, bch_ptr_bad); if (k) { btree_node_prefetch(b, k); @@ -1959,7 +1953,7 @@ static int bch_btree_check_thread(void * struct btree_check_info *info = arg; struct btree_check_state *check_state = info->state; struct cache_set *c = check_state->c; - struct btree_iter iter; + struct btree_iter_stack iter; struct bkey *k, *p; int cur_idx, prev_idx, skip_nr; @@ -1967,11 +1961,9 @@ static int bch_btree_check_thread(void * cur_idx = prev_idx = 0; ret = 0; - min_heap_init(&iter.heap, NULL, MAX_BSETS); - /* root node keys are checked before thread created */ - bch_btree_iter_init(&c->root->keys, &iter, NULL); - k = bch_btree_iter_next_filter(&iter, &c->root->keys, bch_ptr_bad); + bch_btree_iter_stack_init(&c->root->keys, &iter, NULL); + k = bch_btree_iter_next_filter(&iter.iter, &c->root->keys, bch_ptr_bad); BUG_ON(!k); p = k; @@ -1989,7 +1981,7 @@ static int bch_btree_check_thread(void * skip_nr = cur_idx - prev_idx; while (skip_nr) { - k = bch_btree_iter_next_filter(&iter, + k = bch_btree_iter_next_filter(&iter.iter, &c->root->keys, bch_ptr_bad); if (k) @@ -2062,11 +2054,9 @@ int bch_btree_check(struct cache_set *c) int ret = 0; int i; struct bkey *k = NULL; - struct btree_iter iter; + struct btree_iter_stack iter; struct btree_check_state check_state; - min_heap_init(&iter.heap, NULL, MAX_BSETS); - /* check and mark root node keys */ for_each_key_filter(&c->root->keys, k, &iter, bch_ptr_invalid) bch_initial_mark_key(c, c->root->level, k); @@ -2560,12 +2550,11 @@ static int bch_btree_map_nodes_recurse(s if (b->level) { struct bkey *k; - struct btree_iter iter; + struct btree_iter_stack iter; - min_heap_init(&iter.heap, NULL, MAX_BSETS); - bch_btree_iter_init(&b->keys, &iter, from); + bch_btree_iter_stack_init(&b->keys, &iter, from); - while ((k = bch_btree_iter_next_filter(&iter, &b->keys, + while ((k = bch_btree_iter_next_filter(&iter.iter, &b->keys, bch_ptr_bad))) { ret = bcache_btree(map_nodes_recurse, k, b, op, from, fn, flags); @@ -2594,12 +2583,12 @@ int bch_btree_map_keys_recurse(struct bt { int ret = MAP_CONTINUE; struct bkey *k; - struct btree_iter iter; + struct btree_iter_stack iter; - min_heap_init(&iter.heap, NULL, MAX_BSETS); - bch_btree_iter_init(&b->keys, &iter, from); + bch_btree_iter_stack_init(&b->keys, &iter, from); - while ((k = bch_btree_iter_next_filter(&iter, &b->keys, bch_ptr_bad))) { + while ((k = bch_btree_iter_next_filter(&iter.iter, &b->keys, + bch_ptr_bad))) { ret = !b->level ? fn(op, b, k) : bcache_btree(map_keys_recurse, k, --- a/drivers/md/bcache/extents.c~revert-bcache-remove-heap-related-macros-and-switch-to-generic-min_heap +++ a/drivers/md/bcache/extents.c @@ -33,16 +33,15 @@ static void sort_key_next(struct btree_i i->k = bkey_next(i->k); if (i->k == i->end) - *i = iter->heap.data[--iter->heap.nr]; + *i = iter->data[--iter->used]; } -static bool new_bch_key_sort_cmp(const void *l, const void *r, void *args) +static bool bch_key_sort_cmp(struct btree_iter_set l, + struct btree_iter_set r) { - struct btree_iter_set *_l = (struct btree_iter_set *)l; - struct btree_iter_set *_r = (struct btree_iter_set *)r; - int64_t c = bkey_cmp(_l->k, _r->k); + int64_t c = bkey_cmp(l.k, r.k); - return !(c ? c > 0 : _l->k < _r->k); + return c ? c > 0 : l.k < r.k; } static bool __ptr_invalid(struct cache_set *c, const struct bkey *k) @@ -239,7 +238,7 @@ static bool bch_btree_ptr_insert_fixup(s } const struct btree_keys_ops bch_btree_keys_ops = { - .sort_cmp = new_bch_key_sort_cmp, + .sort_cmp = bch_key_sort_cmp, .insert_fixup = bch_btree_ptr_insert_fixup, .key_invalid = bch_btree_ptr_invalid, .key_bad = bch_btree_ptr_bad, @@ -256,36 +255,22 @@ const struct btree_keys_ops bch_btree_ke * Necessary for btree_sort_fixup() - if there are multiple keys that compare * equal in different sets, we have to process them newest to oldest. */ - -static bool new_bch_extent_sort_cmp(const void *l, const void *r, void __always_unused *args) -{ - struct btree_iter_set *_l = (struct btree_iter_set *)l; - struct btree_iter_set *_r = (struct btree_iter_set *)r; - int64_t c = bkey_cmp(&START_KEY(_l->k), &START_KEY(_r->k)); - - return !(c ? c > 0 : _l->k < _r->k); -} - -static inline void new_btree_iter_swap(void *iter1, void *iter2, void __always_unused *args) +static bool bch_extent_sort_cmp(struct btree_iter_set l, + struct btree_iter_set r) { - struct btree_iter_set *_iter1 = iter1; - struct btree_iter_set *_iter2 = iter2; + int64_t c = bkey_cmp(&START_KEY(l.k), &START_KEY(r.k)); - swap(*_iter1, *_iter2); + return c ? c > 0 : l.k < r.k; } static struct bkey *bch_extent_sort_fixup(struct btree_iter *iter, struct bkey *tmp) { - const struct min_heap_callbacks callbacks = { - .less = new_bch_extent_sort_cmp, - .swp = new_btree_iter_swap, - }; - while (iter->heap.nr > 1) { - struct btree_iter_set *top = iter->heap.data, *i = top + 1; + while (iter->used > 1) { + struct btree_iter_set *top = iter->data, *i = top + 1; - if (iter->heap.nr > 2 && - !new_bch_extent_sort_cmp(&i[0], &i[1], NULL)) + if (iter->used > 2 && + bch_extent_sort_cmp(i[0], i[1])) i++; if (bkey_cmp(top->k, &START_KEY(i->k)) <= 0) @@ -293,7 +278,7 @@ static struct bkey *bch_extent_sort_fixu if (!KEY_SIZE(i->k)) { sort_key_next(iter, i); - min_heap_sift_down(&iter->heap, i - top, &callbacks, NULL); + heap_sift(iter, i - top, bch_extent_sort_cmp); continue; } @@ -303,7 +288,7 @@ static struct bkey *bch_extent_sort_fixu else bch_cut_front(top->k, i->k); - min_heap_sift_down(&iter->heap, i - top, &callbacks, NULL); + heap_sift(iter, i - top, bch_extent_sort_cmp); } else { /* can't happen because of comparison func */ BUG_ON(!bkey_cmp(&START_KEY(top->k), &START_KEY(i->k))); @@ -313,7 +298,7 @@ static struct bkey *bch_extent_sort_fixu bch_cut_back(&START_KEY(i->k), tmp); bch_cut_front(i->k, top->k); - min_heap_sift_down(&iter->heap, 0, &callbacks, NULL); + heap_sift(iter, 0, bch_extent_sort_cmp); return tmp; } else { @@ -633,7 +618,7 @@ static bool bch_extent_merge(struct btre } const struct btree_keys_ops bch_extent_keys_ops = { - .sort_cmp = new_bch_extent_sort_cmp, + .sort_cmp = bch_extent_sort_cmp, .sort_fixup = bch_extent_sort_fixup, .insert_fixup = bch_extent_insert_fixup, .key_invalid = bch_extent_invalid, --- a/drivers/md/bcache/movinggc.c~revert-bcache-remove-heap-related-macros-and-switch-to-generic-min_heap +++ a/drivers/md/bcache/movinggc.c @@ -182,27 +182,16 @@ err: if (!IS_ERR_OR_NULL(w->private)) closure_sync(&cl); } -static bool new_bucket_cmp(const void *l, const void *r, void __always_unused *args) +static bool bucket_cmp(struct bucket *l, struct bucket *r) { - struct bucket **_l = (struct bucket **)l; - struct bucket **_r = (struct bucket **)r; - - return GC_SECTORS_USED(*_l) >= GC_SECTORS_USED(*_r); -} - -static void new_bucket_swap(void *l, void *r, void __always_unused *args) -{ - struct bucket **_l = l; - struct bucket **_r = r; - - swap(*_l, *_r); + return GC_SECTORS_USED(l) < GC_SECTORS_USED(r); } static unsigned int bucket_heap_top(struct cache *ca) { struct bucket *b; - return (b = min_heap_peek(&ca->heap)[0]) ? GC_SECTORS_USED(b) : 0; + return (b = heap_peek(&ca->heap)) ? GC_SECTORS_USED(b) : 0; } void bch_moving_gc(struct cache_set *c) @@ -210,10 +199,6 @@ void bch_moving_gc(struct cache_set *c) struct cache *ca = c->cache; struct bucket *b; unsigned long sectors_to_move, reserve_sectors; - const struct min_heap_callbacks callbacks = { - .less = new_bucket_cmp, - .swp = new_bucket_swap, - }; if (!c->copy_gc_enabled) return; @@ -224,7 +209,7 @@ void bch_moving_gc(struct cache_set *c) reserve_sectors = ca->sb.bucket_size * fifo_used(&ca->free[RESERVE_MOVINGGC]); - ca->heap.nr = 0; + ca->heap.used = 0; for_each_bucket(b, ca) { if (GC_MARK(b) == GC_MARK_METADATA || @@ -233,31 +218,25 @@ void bch_moving_gc(struct cache_set *c) atomic_read(&b->pin)) continue; - if (!min_heap_full(&ca->heap)) { + if (!heap_full(&ca->heap)) { sectors_to_move += GC_SECTORS_USED(b); - min_heap_push(&ca->heap, &b, &callbacks, NULL); - } else if (!new_bucket_cmp(&b, min_heap_peek(&ca->heap), ca)) { + heap_add(&ca->heap, b, bucket_cmp); + } else if (bucket_cmp(b, heap_peek(&ca->heap))) { sectors_to_move -= bucket_heap_top(ca); sectors_to_move += GC_SECTORS_USED(b); ca->heap.data[0] = b; - min_heap_sift_down(&ca->heap, 0, &callbacks, NULL); + heap_sift(&ca->heap, 0, bucket_cmp); } } while (sectors_to_move > reserve_sectors) { - if (ca->heap.nr) { - b = min_heap_peek(&ca->heap)[0]; - min_heap_pop(&ca->heap, &callbacks, NULL); - } + heap_pop(&ca->heap, b, bucket_cmp); sectors_to_move -= GC_SECTORS_USED(b); } - while (ca->heap.nr) { - b = min_heap_peek(&ca->heap)[0]; - min_heap_pop(&ca->heap, &callbacks, NULL); + while (heap_pop(&ca->heap, b, bucket_cmp)) SET_GC_MOVE(b, 1); - } mutex_unlock(&c->bucket_lock); --- a/drivers/md/bcache/super.c~revert-bcache-remove-heap-related-macros-and-switch-to-generic-min_heap +++ a/drivers/md/bcache/super.c @@ -1912,7 +1912,8 @@ struct cache_set *bch_cache_set_alloc(st INIT_LIST_HEAD(&c->btree_cache_freed); INIT_LIST_HEAD(&c->data_buckets); - iter_size = ((meta_bucket_pages(sb) * PAGE_SECTORS) / sb->block_size) * + iter_size = sizeof(struct btree_iter) + + ((meta_bucket_pages(sb) * PAGE_SECTORS) / sb->block_size) * sizeof(struct btree_iter_set); c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL); --- a/drivers/md/bcache/sysfs.c~revert-bcache-remove-heap-related-macros-and-switch-to-generic-min_heap +++ a/drivers/md/bcache/sysfs.c @@ -660,9 +660,7 @@ static unsigned int bch_root_usage(struc unsigned int bytes = 0; struct bkey *k; struct btree *b; - struct btree_iter iter; - - min_heap_init(&iter.heap, NULL, MAX_BSETS); + struct btree_iter_stack iter; goto lock_root; --- a/drivers/md/bcache/util.h~revert-bcache-remove-heap-related-macros-and-switch-to-generic-min_heap +++ a/drivers/md/bcache/util.h @@ -9,7 +9,6 @@ #include <linux/kernel.h> #include <linux/sched/clock.h> #include <linux/llist.h> -#include <linux/min_heap.h> #include <linux/ratelimit.h> #include <linux/vmalloc.h> #include <linux/workqueue.h> @@ -31,10 +30,16 @@ struct closure; #endif +#define DECLARE_HEAP(type, name) \ + struct { \ + size_t size, used; \ + type *data; \ + } name + #define init_heap(heap, _size, gfp) \ ({ \ size_t _bytes; \ - (heap)->nr = 0; \ + (heap)->used = 0; \ (heap)->size = (_size); \ _bytes = (heap)->size * sizeof(*(heap)->data); \ (heap)->data = kvmalloc(_bytes, (gfp) & GFP_KERNEL); \ @@ -47,6 +52,64 @@ do { \ (heap)->data = NULL; \ } while (0) +#define heap_swap(h, i, j) swap((h)->data[i], (h)->data[j]) + +#define heap_sift(h, i, cmp) \ +do { \ + size_t _r, _j = i; \ + \ + for (; _j * 2 + 1 < (h)->used; _j = _r) { \ + _r = _j * 2 + 1; \ + if (_r + 1 < (h)->used && \ + cmp((h)->data[_r], (h)->data[_r + 1])) \ + _r++; \ + \ + if (cmp((h)->data[_r], (h)->data[_j])) \ + break; \ + heap_swap(h, _r, _j); \ + } \ +} while (0) + +#define heap_sift_down(h, i, cmp) \ +do { \ + while (i) { \ + size_t p = (i - 1) / 2; \ + if (cmp((h)->data[i], (h)->data[p])) \ + break; \ + heap_swap(h, i, p); \ + i = p; \ + } \ +} while (0) + +#define heap_add(h, d, cmp) \ +({ \ + bool _r = !heap_full(h); \ + if (_r) { \ + size_t _i = (h)->used++; \ + (h)->data[_i] = d; \ + \ + heap_sift_down(h, _i, cmp); \ + heap_sift(h, _i, cmp); \ + } \ + _r; \ +}) + +#define heap_pop(h, d, cmp) \ +({ \ + bool _r = (h)->used; \ + if (_r) { \ + (d) = (h)->data[0]; \ + (h)->used--; \ + heap_swap(h, 0, (h)->used); \ + heap_sift(h, 0, cmp); \ + } \ + _r; \ +}) + +#define heap_peek(h) ((h)->used ? (h)->data[0] : NULL) + +#define heap_full(h) ((h)->used == (h)->size) + #define DECLARE_FIFO(type, name) \ struct { \ size_t front, back, size, mask; \ --- a/drivers/md/bcache/writeback.c~revert-bcache-remove-heap-related-macros-and-switch-to-generic-min_heap +++ a/drivers/md/bcache/writeback.c @@ -908,16 +908,15 @@ static int bch_dirty_init_thread(void *a struct dirty_init_thrd_info *info = arg; struct bch_dirty_init_state *state = info->state; struct cache_set *c = state->c; - struct btree_iter iter; + struct btree_iter_stack iter; struct bkey *k, *p; int cur_idx, prev_idx, skip_nr; k = p = NULL; prev_idx = 0; - min_heap_init(&iter.heap, NULL, MAX_BSETS); - bch_btree_iter_init(&c->root->keys, &iter, NULL); - k = bch_btree_iter_next_filter(&iter, &c->root->keys, bch_ptr_bad); + bch_btree_iter_stack_init(&c->root->keys, &iter, NULL); + k = bch_btree_iter_next_filter(&iter.iter, &c->root->keys, bch_ptr_bad); BUG_ON(!k); p = k; @@ -931,7 +930,7 @@ static int bch_dirty_init_thread(void *a skip_nr = cur_idx - prev_idx; while (skip_nr) { - k = bch_btree_iter_next_filter(&iter, + k = bch_btree_iter_next_filter(&iter.iter, &c->root->keys, bch_ptr_bad); if (k) @@ -980,13 +979,11 @@ void bch_sectors_dirty_init(struct bcach int i; struct btree *b = NULL; struct bkey *k = NULL; - struct btree_iter iter; + struct btree_iter_stack iter; struct sectors_dirty_init op; struct cache_set *c = d->c; struct bch_dirty_init_state state; - min_heap_init(&iter.heap, NULL, MAX_BSETS); - retry_lock: b = c->root; rw_lock(0, b, b->level); _ Patches currently in -mm which might be from visitorckw(a)gmail.com are lib-math-gcd-use-static-key-to-select-implementation-at-runtime.patch riscv-optimize-gcd-code-size-when-config_riscv_isa_zbb-is-disabled.patch riscv-optimize-gcd-performance-on-risc-v-without-zbb-extension.patch

2 weeks, 1 day

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[merged mm-hotfixes-stable] revert-bcache-update-min_heap_callbacks-to-use-default-builtin-swap.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: Revert "bcache: update min_heap_callbacks to use default builtin swap" has been removed from the -mm tree. Its filename was revert-bcache-update-min_heap_callbacks-to-use-default-builtin-swap.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Kuan-Wei Chiu <visitorckw(a)gmail.com> Subject: Revert "bcache: update min_heap_callbacks to use default builtin swap" Date: Sun, 15 Jun 2025 04:23:51 +0800 Patch series "bcache: Revert min_heap migration due to performance regression". This patch series reverts the migration of bcache from its original heap implementation to the generic min_heap library. While the original change aimed to simplify the code and improve maintainability, it introduced a severe performance regression in real-world scenarios. As reported by Robert, systems using bcache now suffer from periodic latency spikes, with P100 (max) latency increasing from 600 ms to 2.4 seconds every 5 minutes. This degrades bcache's value as a low-latency caching layer, and leads to frequent timeouts and application stalls in production environments. The primary cause of this regression is the behavior of the generic min_heap implementation's bottom-up sift_down, which performs up to 2 * log2(n) comparisons when many elements are equal. The original top-down variant used by bcache only required O(1) comparisons in such cases. The issue was further exacerbated by commit 92a8b224b833 ("lib/min_heap: introduce non-inline versions of min heap API functions"), which introduced non-inlined versions of the min_heap API, adding function call overhead to a performance-critical hot path. This patch (of 3): This reverts commit 3d8a9a1c35227c3f1b0bd132c9f0a80dbda07b65. Although removing the custom swap function simplified the code, this change is part of a broader migration to the generic min_heap API that introduced significant performance regressions in bcache. As reported by Robert, bcache now suffers from latency spikes, with P100 (max) latency increasing from 600 ms to 2.4 seconds every 5 minutes. These regressions degrade bcache's effectiveness as a low-latency cache layer and lead to frequent timeouts and application stalls in production environments. This revert is part of a series of changes to restore previous performance by undoing the min_heap transition. Link: https://lkml.kernel.org/r/20250614202353.1632957-1-visitorckw@gmail.com Link: https://lore.kernel.org/lkml/CAJhEC05+0S69z+3+FB2Cd0hD+pCRyWTKLEOsc8BOmH73p… Link: https://lkml.kernel.org/r/20250614202353.1632957-2-visitorckw@gmail.com Fixes: 866898efbb25 ("bcache: remove heap-related macros and switch to generic min_heap") Fixes: 92a8b224b833 ("lib/min_heap: introduce non-inline versions of min heap API functions") Signed-off-by: Kuan-Wei Chiu <visitorckw(a)gmail.com> Reported-by: Robert Pang <robertpang(a)google.com> Closes: https://lore.kernel.org/linux-bcache/CAJhEC06F_AtrPgw2-7CvCqZgeStgCtitbD-ry… Acked-by: Coly Li <colyli(a)kernel.org> Cc: Ching-Chun (Jim) Huang <jserv(a)ccns.ncku.edu.tw> Cc: Kent Overstreet <kent.overstreet(a)linux.dev> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- drivers/md/bcache/alloc.c | 11 +++++++++-- drivers/md/bcache/bset.c | 14 +++++++++++--- drivers/md/bcache/extents.c | 10 +++++++++- drivers/md/bcache/movinggc.c | 10 +++++++++- 4 files changed, 38 insertions(+), 7 deletions(-) --- a/drivers/md/bcache/alloc.c~revert-bcache-update-min_heap_callbacks-to-use-default-builtin-swap +++ a/drivers/md/bcache/alloc.c @@ -189,16 +189,23 @@ static inline bool new_bucket_min_cmp(co return new_bucket_prio(ca, *lhs) < new_bucket_prio(ca, *rhs); } +static inline void new_bucket_swap(void *l, void *r, void __always_unused *args) +{ + struct bucket **lhs = l, **rhs = r; + + swap(*lhs, *rhs); +} + static void invalidate_buckets_lru(struct cache *ca) { struct bucket *b; const struct min_heap_callbacks bucket_max_cmp_callback = { .less = new_bucket_max_cmp, - .swp = NULL, + .swp = new_bucket_swap, }; const struct min_heap_callbacks bucket_min_cmp_callback = { .less = new_bucket_min_cmp, - .swp = NULL, + .swp = new_bucket_swap, }; ca->heap.nr = 0; --- a/drivers/md/bcache/bset.c~revert-bcache-update-min_heap_callbacks-to-use-default-builtin-swap +++ a/drivers/md/bcache/bset.c @@ -1093,6 +1093,14 @@ static inline bool new_btree_iter_cmp(co return bkey_cmp(_l->k, _r->k) <= 0; } +static inline void new_btree_iter_swap(void *iter1, void *iter2, void __always_unused *args) +{ + struct btree_iter_set *_iter1 = iter1; + struct btree_iter_set *_iter2 = iter2; + + swap(*_iter1, *_iter2); +} + static inline bool btree_iter_end(struct btree_iter *iter) { return !iter->heap.nr; @@ -1103,7 +1111,7 @@ void bch_btree_iter_push(struct btree_it { const struct min_heap_callbacks callbacks = { .less = new_btree_iter_cmp, - .swp = NULL, + .swp = new_btree_iter_swap, }; if (k != end) @@ -1149,7 +1157,7 @@ static inline struct bkey *__bch_btree_i struct bkey *ret = NULL; const struct min_heap_callbacks callbacks = { .less = cmp, - .swp = NULL, + .swp = new_btree_iter_swap, }; if (!btree_iter_end(iter)) { @@ -1223,7 +1231,7 @@ static void btree_mergesort(struct btree : bch_ptr_invalid; const struct min_heap_callbacks callbacks = { .less = b->ops->sort_cmp, - .swp = NULL, + .swp = new_btree_iter_swap, }; /* Heapify the iterator, using our comparison function */ --- a/drivers/md/bcache/extents.c~revert-bcache-update-min_heap_callbacks-to-use-default-builtin-swap +++ a/drivers/md/bcache/extents.c @@ -266,12 +266,20 @@ static bool new_bch_extent_sort_cmp(cons return !(c ? c > 0 : _l->k < _r->k); } +static inline void new_btree_iter_swap(void *iter1, void *iter2, void __always_unused *args) +{ + struct btree_iter_set *_iter1 = iter1; + struct btree_iter_set *_iter2 = iter2; + + swap(*_iter1, *_iter2); +} + static struct bkey *bch_extent_sort_fixup(struct btree_iter *iter, struct bkey *tmp) { const struct min_heap_callbacks callbacks = { .less = new_bch_extent_sort_cmp, - .swp = NULL, + .swp = new_btree_iter_swap, }; while (iter->heap.nr > 1) { struct btree_iter_set *top = iter->heap.data, *i = top + 1; --- a/drivers/md/bcache/movinggc.c~revert-bcache-update-min_heap_callbacks-to-use-default-builtin-swap +++ a/drivers/md/bcache/movinggc.c @@ -190,6 +190,14 @@ static bool new_bucket_cmp(const void *l return GC_SECTORS_USED(*_l) >= GC_SECTORS_USED(*_r); } +static void new_bucket_swap(void *l, void *r, void __always_unused *args) +{ + struct bucket **_l = l; + struct bucket **_r = r; + + swap(*_l, *_r); +} + static unsigned int bucket_heap_top(struct cache *ca) { struct bucket *b; @@ -204,7 +212,7 @@ void bch_moving_gc(struct cache_set *c) unsigned long sectors_to_move, reserve_sectors; const struct min_heap_callbacks callbacks = { .less = new_bucket_cmp, - .swp = NULL, + .swp = new_bucket_swap, }; if (!c->copy_gc_enabled) _ Patches currently in -mm which might be from visitorckw(a)gmail.com are lib-math-gcd-use-static-key-to-select-implementation-at-runtime.patch riscv-optimize-gcd-code-size-when-config_riscv_isa_zbb-is-disabled.patch riscv-optimize-gcd-performance-on-risc-v-without-zbb-extension.patch

2 weeks, 1 day

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[merged mm-hotfixes-stable] mm-userfaultfd-fix-race-of-userfaultfd_move-and-swap-cache.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm: userfaultfd: fix race of userfaultfd_move and swap cache has been removed from the -mm tree. Its filename was mm-userfaultfd-fix-race-of-userfaultfd_move-and-swap-cache.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Kairui Song <kasong(a)tencent.com> Subject: mm: userfaultfd: fix race of userfaultfd_move and swap cache Date: Wed, 4 Jun 2025 23:10:38 +0800 This commit fixes two kinds of races, they may have different results: Barry reported a BUG_ON in commit c50f8e6053b0, we may see the same BUG_ON if the filemap lookup returned NULL and folio is added to swap cache after that. If another kind of race is triggered (folio changed after lookup) we may see RSS counter is corrupted: [ 406.893936] BUG: Bad rss-counter state mm:ffff0000c5a9ddc0 type:MM_ANONPAGES val:-1 [ 406.894071] BUG: Bad rss-counter state mm:ffff0000c5a9ddc0 type:MM_SHMEMPAGES val:1 Because the folio is being accounted to the wrong VMA. I'm not sure if there will be any data corruption though, seems no. The issues above are critical already. On seeing a swap entry PTE, userfaultfd_move does a lockless swap cache lookup, and tries to move the found folio to the faulting vma. Currently, it relies on checking the PTE value to ensure that the moved folio still belongs to the src swap entry and that no new folio has been added to the swap cache, which turns out to be unreliable. While working and reviewing the swap table series with Barry, following existing races are observed and reproduced [1]: In the example below, move_pages_pte is moving src_pte to dst_pte, where src_pte is a swap entry PTE holding swap entry S1, and S1 is not in the swap cache: CPU1 CPU2 userfaultfd_move move_pages_pte() entry = pte_to_swp_entry(orig_src_pte); // Here it got entry = S1 ... < interrupted> ... <swapin src_pte, alloc and use folio A> // folio A is a new allocated folio // and get installed into src_pte <frees swap entry S1> // src_pte now points to folio A, S1 // has swap count == 0, it can be freed // by folio_swap_swap or swap // allocator's reclaim. <try to swap out another folio B> // folio B is a folio in another VMA. <put folio B to swap cache using S1 > // S1 is freed, folio B can use it // for swap out with no problem. ... folio = filemap_get_folio(S1) // Got folio B here !!! ... < interrupted again> ... <swapin folio B and free S1> // Now S1 is free to be used again. <swapout src_pte & folio A using S1> // Now src_pte is a swap entry PTE // holding S1 again. folio_trylock(folio) move_swap_pte double_pt_lock is_pte_pages_stable // Check passed because src_pte == S1 folio_move_anon_rmap(...) // Moved invalid folio B here !!! The race window is very short and requires multiple collisions of multiple rare events, so it's very unlikely to happen, but with a deliberately constructed reproducer and increased time window, it can be reproduced easily. This can be fixed by checking if the folio returned by filemap is the valid swap cache folio after acquiring the folio lock. Another similar race is possible: filemap_get_folio may return NULL, but folio (A) could be swapped in and then swapped out again using the same swap entry after the lookup. In such a case, folio (A) may remain in the swap cache, so it must be moved too: CPU1 CPU2 userfaultfd_move move_pages_pte() entry = pte_to_swp_entry(orig_src_pte); // Here it got entry = S1, and S1 is not in swap cache folio = filemap_get_folio(S1) // Got NULL ... < interrupted again> ... <swapin folio A and free S1> <swapout folio A re-using S1> move_swap_pte double_pt_lock is_pte_pages_stable // Check passed because src_pte == S1 folio_move_anon_rmap(...) // folio A is ignored !!! Fix this by checking the swap cache again after acquiring the src_pte lock. And to avoid the filemap overhead, we check swap_map directly [2]. The SWP_SYNCHRONOUS_IO path does make the problem more complex, but so far we don't need to worry about that, since folios can only be exposed to the swap cache in the swap out path, and this is covered in this patch by checking the swap cache again after acquiring the src_pte lock. Testing with a simple C program that allocates and moves several GB of memory did not show any observable performance change. Link: https://lkml.kernel.org/r/20250604151038.21968-1-ryncsn@gmail.com Fixes: adef440691ba ("userfaultfd: UFFDIO_MOVE uABI") Signed-off-by: Kairui Song <kasong(a)tencent.com> Closes: https://lore.kernel.org/linux-mm/CAMgjq7B1K=6OOrK2OUZ0-tqCzi+EJt+2_K97TPGoS… [1] Link: https://lore.kernel.org/all/CAGsJ_4yJhJBo16XhiC-nUzSheyX-V3-nFE+tAi=8Y560K8… [2] Reviewed-by: Lokesh Gidra <lokeshgidra(a)google.com> Acked-by: Peter Xu <peterx(a)redhat.com> Reviewed-by: Suren Baghdasaryan <surenb(a)google.com> Reviewed-by: Barry Song <baohua(a)kernel.org> Reviewed-by: Chris Li <chrisl(a)kernel.org> Cc: Andrea Arcangeli <aarcange(a)redhat.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: Kairui Song <kasong(a)tencent.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/userfaultfd.c | 33 +++++++++++++++++++++++++++++++-- 1 file changed, 31 insertions(+), 2 deletions(-) --- a/mm/userfaultfd.c~mm-userfaultfd-fix-race-of-userfaultfd_move-and-swap-cache +++ a/mm/userfaultfd.c @@ -1084,8 +1084,18 @@ static int move_swap_pte(struct mm_struc pte_t orig_dst_pte, pte_t orig_src_pte, pmd_t *dst_pmd, pmd_t dst_pmdval, spinlock_t *dst_ptl, spinlock_t *src_ptl, - struct folio *src_folio) + struct folio *src_folio, + struct swap_info_struct *si, swp_entry_t entry) { + /* + * Check if the folio still belongs to the target swap entry after + * acquiring the lock. Folio can be freed in the swap cache while + * not locked. + */ + if (src_folio && unlikely(!folio_test_swapcache(src_folio) || + entry.val != src_folio->swap.val)) + return -EAGAIN; + double_pt_lock(dst_ptl, src_ptl); if (!is_pte_pages_stable(dst_pte, src_pte, orig_dst_pte, orig_src_pte, @@ -1102,6 +1112,25 @@ static int move_swap_pte(struct mm_struc if (src_folio) { folio_move_anon_rmap(src_folio, dst_vma); src_folio->index = linear_page_index(dst_vma, dst_addr); + } else { + /* + * Check if the swap entry is cached after acquiring the src_pte + * lock. Otherwise, we might miss a newly loaded swap cache folio. + * + * Check swap_map directly to minimize overhead, READ_ONCE is sufficient. + * We are trying to catch newly added swap cache, the only possible case is + * when a folio is swapped in and out again staying in swap cache, using the + * same entry before the PTE check above. The PTL is acquired and released + * twice, each time after updating the swap_map's flag. So holding + * the PTL here ensures we see the updated value. False positive is possible, + * e.g. SWP_SYNCHRONOUS_IO swapin may set the flag without touching the + * cache, or during the tiny synchronization window between swap cache and + * swap_map, but it will be gone very quickly, worst result is retry jitters. + */ + if (READ_ONCE(si->swap_map[swp_offset(entry)]) & SWAP_HAS_CACHE) { + double_pt_unlock(dst_ptl, src_ptl); + return -EAGAIN; + } } orig_src_pte = ptep_get_and_clear(mm, src_addr, src_pte); @@ -1412,7 +1441,7 @@ retry: } err = move_swap_pte(mm, dst_vma, dst_addr, src_addr, dst_pte, src_pte, orig_dst_pte, orig_src_pte, dst_pmd, dst_pmdval, - dst_ptl, src_ptl, src_folio); + dst_ptl, src_ptl, src_folio, si, entry); } out: _ Patches currently in -mm which might be from kasong(a)tencent.com are mm-list_lru-refactor-the-locking-code.patch mm-shmem-swap-improve-cached-mthp-handling-and-fix-potential-hung.patch mm-shmem-swap-avoid-redundant-xarray-lookup-during-swapin.patch mm-shmem-swap-improve-mthp-swapin-process.patch mm-shmem-swap-avoid-false-positive-swap-cache-lookup.patch

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[merged mm-hotfixes-stable] mm-gup-revert-mm-gup-fix-infinite-loop-within-__get_longterm_locked.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/gup: revert "mm: gup: fix infinite loop within __get_longterm_locked" has been removed from the -mm tree. Its filename was mm-gup-revert-mm-gup-fix-infinite-loop-within-__get_longterm_locked.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: David Hildenbrand <david(a)redhat.com> Subject: mm/gup: revert "mm: gup: fix infinite loop within __get_longterm_locked" Date: Wed, 11 Jun 2025 15:13:14 +0200 After commit 1aaf8c122918 ("mm: gup: fix infinite loop within __get_longterm_locked") we are able to longterm pin folios that are not supposed to get longterm pinned, simply because they temporarily have the LRU flag cleared (esp. temporarily isolated). For example, two __get_longterm_locked() callers can race, or __get_longterm_locked() can race with anything else that temporarily isolates folios. The introducing commit mentions the use case of a driver that uses vm_ops->fault to insert pages allocated through cma_alloc() into the page tables, assuming they can later get longterm pinned. These pages/ folios would never have the LRU flag set and consequently cannot get isolated. There is no known in-tree user making use of that so far, fortunately. To handle that in the future -- and avoid retrying forever to isolate/migrate them -- we will need a different mechanism for the CMA area *owner* to indicate that it actually already allocated the page and is fine with longterm pinning it. The LRU flag is not suitable for that. Probably we can lookup the relevant CMA area and query the bitmap; we only have have to care about some races, probably. If already allocated, we could just allow longterm pinning) Anyhow, let's fix the "must not be longterm pinned" problem first by reverting the original commit. Link: https://lkml.kernel.org/r/20250611131314.594529-1-david@redhat.com Fixes: 1aaf8c122918 ("mm: gup: fix infinite loop within __get_longterm_locked") Signed-off-by: David Hildenbrand <david(a)redhat.com> Closes: https://lore.kernel.org/all/20250522092755.GA3277597@tiffany/ Reported-by: Hyesoo Yu <hyesoo.yu(a)samsung.com> Reviewed-by: John Hubbard <jhubbard(a)nvidia.com> Cc: Jason Gunthorpe <jgg(a)ziepe.ca> Cc: Peter Xu <peterx(a)redhat.com> Cc: Zhaoyang Huang <zhaoyang.huang(a)unisoc.com> Cc: Aijun Sun <aijun.sun(a)unisoc.com> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/gup.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) --- a/mm/gup.c~mm-gup-revert-mm-gup-fix-infinite-loop-within-__get_longterm_locked +++ a/mm/gup.c @@ -2303,13 +2303,13 @@ static void pofs_unpin(struct pages_or_f /* * Returns the number of collected folios. Return value is always >= 0. */ -static void collect_longterm_unpinnable_folios( +static unsigned long collect_longterm_unpinnable_folios( struct list_head *movable_folio_list, struct pages_or_folios *pofs) { + unsigned long i, collected = 0; struct folio *prev_folio = NULL; bool drain_allow = true; - unsigned long i; for (i = 0; i < pofs->nr_entries; i++) { struct folio *folio = pofs_get_folio(pofs, i); @@ -2321,6 +2321,8 @@ static void collect_longterm_unpinnable_ if (folio_is_longterm_pinnable(folio)) continue; + collected++; + if (folio_is_device_coherent(folio)) continue; @@ -2342,6 +2344,8 @@ static void collect_longterm_unpinnable_ NR_ISOLATED_ANON + folio_is_file_lru(folio), folio_nr_pages(folio)); } + + return collected; } /* @@ -2418,9 +2422,11 @@ static long check_and_migrate_movable_pages_or_folios(struct pages_or_folios *pofs) { LIST_HEAD(movable_folio_list); + unsigned long collected; - collect_longterm_unpinnable_folios(&movable_folio_list, pofs); - if (list_empty(&movable_folio_list)) + collected = collect_longterm_unpinnable_folios(&movable_folio_list, + pofs); + if (!collected) return 0; return migrate_longterm_unpinnable_folios(&movable_folio_list, pofs); _ Patches currently in -mm which might be from david(a)redhat.com are fs-proc-task_mmu-fix-page_is_pfnzero-detection-for-the-huge-zero-folio.patch mm-gup-remove-vm_bug_ons.patch mm-gup-remove-vm_bug_ons-fix.patch mm-huge_memory-dont-ignore-queried-cachemode-in-vmf_insert_pfn_pud.patch mm-huge_memory-dont-mark-refcounted-folios-special-in-vmf_insert_folio_pmd.patch mm-huge_memory-dont-mark-refcounted-folios-special-in-vmf_insert_folio_pud.patch

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