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[patch 088/167] mm, hmm: use devm semantics for hmm_devmem_{add, remove}

by akpm＠linux-foundation.org

From: Dan Williams <dan.j.williams(a)intel.com> Subject: mm, hmm: use devm semantics for hmm_devmem_{add, remove} devm semantics arrange for resources to be torn down when device-driver-probe fails or when device-driver-release completes. Similar to devm_memremap_pages() there is no need to support an explicit remove operation when the users properly adhere to devm semantics. Note that devm_kzalloc() automatically handles allocating node-local memory. Link: http://lkml.kernel.org/r/154275559545.76910.9186690723515469051.stgit@dwill… Signed-off-by: Dan Williams <dan.j.williams(a)intel.com> Reviewed-by: Christoph Hellwig <hch(a)lst.de> Reviewed-by: Jérôme Glisse <jglisse(a)redhat.com> Cc: "Jérôme Glisse" <jglisse(a)redhat.com> Cc: Logan Gunthorpe <logang(a)deltatee.com> Cc: Balbir Singh <bsingharora(a)gmail.com> Cc: Michal Hocko <mhocko(a)suse.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- --- a/include/linux/hmm.h~mm-hmm-use-devm-semantics-for-hmm_devmem_add-remove +++ a/include/linux/hmm.h @@ -512,8 +512,7 @@ struct hmm_devmem { * enough and allocate struct page for it. * * The device driver can wrap the hmm_devmem struct inside a private device - * driver struct. The device driver must call hmm_devmem_remove() before the - * device goes away and before freeing the hmm_devmem struct memory. + * driver struct. */ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops, struct device *device, @@ -521,7 +520,6 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops, struct device *device, struct resource *res); -void hmm_devmem_remove(struct hmm_devmem *devmem); /* * hmm_devmem_page_set_drvdata - set per-page driver data field --- a/mm/hmm.c~mm-hmm-use-devm-semantics-for-hmm_devmem_add-remove +++ a/mm/hmm.c @@ -987,7 +987,6 @@ static void hmm_devmem_ref_exit(void *da devmem = container_of(ref, struct hmm_devmem, ref); percpu_ref_exit(ref); - devm_remove_action(devmem->device, &hmm_devmem_ref_exit, data); } static void hmm_devmem_ref_kill(void *data) @@ -998,7 +997,6 @@ static void hmm_devmem_ref_kill(void *da devmem = container_of(ref, struct hmm_devmem, ref); percpu_ref_kill(ref); wait_for_completion(&devmem->completion); - devm_remove_action(devmem->device, &hmm_devmem_ref_kill, data); } static int hmm_devmem_fault(struct vm_area_struct *vma, @@ -1036,7 +1034,7 @@ static void hmm_devmem_radix_release(str mutex_unlock(&hmm_devmem_lock); } -static void hmm_devmem_release(struct device *dev, void *data) +static void hmm_devmem_release(void *data) { struct hmm_devmem *devmem = data; struct resource *resource = devmem->resource; @@ -1044,11 +1042,6 @@ static void hmm_devmem_release(struct de struct zone *zone; struct page *page; - if (percpu_ref_tryget_live(&devmem->ref)) { - dev_WARN(dev, "%s: page mapping is still live!\n", __func__); - percpu_ref_put(&devmem->ref); - } - /* pages are dead and unused, undo the arch mapping */ start_pfn = (resource->start & ~(PA_SECTION_SIZE - 1)) >> PAGE_SHIFT; npages = ALIGN(resource_size(resource), PA_SECTION_SIZE) >> PAGE_SHIFT; @@ -1174,19 +1167,6 @@ error: return ret; } -static int hmm_devmem_match(struct device *dev, void *data, void *match_data) -{ - struct hmm_devmem *devmem = data; - - return devmem->resource == match_data; -} - -static void hmm_devmem_pages_remove(struct hmm_devmem *devmem) -{ - devres_release(devmem->device, &hmm_devmem_release, - &hmm_devmem_match, devmem->resource); -} - /* * hmm_devmem_add() - hotplug ZONE_DEVICE memory for device memory * @@ -1214,8 +1194,7 @@ struct hmm_devmem *hmm_devmem_add(const dev_pagemap_get_ops(); - devmem = devres_alloc_node(&hmm_devmem_release, sizeof(*devmem), - GFP_KERNEL, dev_to_node(device)); + devmem = devm_kzalloc(device, sizeof(*devmem), GFP_KERNEL); if (!devmem) return ERR_PTR(-ENOMEM); @@ -1229,11 +1208,11 @@ struct hmm_devmem *hmm_devmem_add(const ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release, 0, GFP_KERNEL); if (ret) - goto error_percpu_ref; + return ERR_PTR(ret); - ret = devm_add_action(device, hmm_devmem_ref_exit, &devmem->ref); + ret = devm_add_action_or_reset(device, hmm_devmem_ref_exit, &devmem->ref); if (ret) - goto error_devm_add_action; + return ERR_PTR(ret); size = ALIGN(size, PA_SECTION_SIZE); addr = min((unsigned long)iomem_resource.end, @@ -1253,16 +1232,12 @@ struct hmm_devmem *hmm_devmem_add(const devmem->resource = devm_request_mem_region(device, addr, size, dev_name(device)); - if (!devmem->resource) { - ret = -ENOMEM; - goto error_no_resource; - } + if (!devmem->resource) + return ERR_PTR(-ENOMEM); break; } - if (!devmem->resource) { - ret = -ERANGE; - goto error_no_resource; - } + if (!devmem->resource) + return ERR_PTR(-ERANGE); devmem->resource->desc = IORES_DESC_DEVICE_PRIVATE_MEMORY; devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT; @@ -1271,28 +1246,13 @@ struct hmm_devmem *hmm_devmem_add(const ret = hmm_devmem_pages_create(devmem); if (ret) - goto error_pages; - - devres_add(device, devmem); + return ERR_PTR(ret); - ret = devm_add_action(device, hmm_devmem_ref_kill, &devmem->ref); - if (ret) { - hmm_devmem_remove(devmem); + ret = devm_add_action_or_reset(device, hmm_devmem_release, devmem); + if (ret) return ERR_PTR(ret); - } return devmem; - -error_pages: - devm_release_mem_region(device, devmem->resource->start, - resource_size(devmem->resource)); -error_no_resource: -error_devm_add_action: - hmm_devmem_ref_kill(&devmem->ref); - hmm_devmem_ref_exit(&devmem->ref); -error_percpu_ref: - devres_free(devmem); - return ERR_PTR(ret); } EXPORT_SYMBOL(hmm_devmem_add); @@ -1308,8 +1268,7 @@ struct hmm_devmem *hmm_devmem_add_resour dev_pagemap_get_ops(); - devmem = devres_alloc_node(&hmm_devmem_release, sizeof(*devmem), - GFP_KERNEL, dev_to_node(device)); + devmem = devm_kzalloc(device, sizeof(*devmem), GFP_KERNEL); if (!devmem) return ERR_PTR(-ENOMEM); @@ -1323,12 +1282,12 @@ struct hmm_devmem *hmm_devmem_add_resour ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release, 0, GFP_KERNEL); if (ret) - goto error_percpu_ref; + return ERR_PTR(ret); - ret = devm_add_action(device, hmm_devmem_ref_exit, &devmem->ref); + ret = devm_add_action_or_reset(device, hmm_devmem_ref_exit, + &devmem->ref); if (ret) - goto error_devm_add_action; - + return ERR_PTR(ret); devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT; devmem->pfn_last = devmem->pfn_first + @@ -1336,60 +1295,22 @@ struct hmm_devmem *hmm_devmem_add_resour ret = hmm_devmem_pages_create(devmem); if (ret) - goto error_devm_add_action; + return ERR_PTR(ret); - devres_add(device, devmem); + ret = devm_add_action_or_reset(device, hmm_devmem_release, devmem); + if (ret) + return ERR_PTR(ret); - ret = devm_add_action(device, hmm_devmem_ref_kill, &devmem->ref); - if (ret) { - hmm_devmem_remove(devmem); + ret = devm_add_action_or_reset(device, hmm_devmem_ref_kill, + &devmem->ref); + if (ret) return ERR_PTR(ret); - } return devmem; - -error_devm_add_action: - hmm_devmem_ref_kill(&devmem->ref); - hmm_devmem_ref_exit(&devmem->ref); -error_percpu_ref: - devres_free(devmem); - return ERR_PTR(ret); } EXPORT_SYMBOL(hmm_devmem_add_resource); /* - * hmm_devmem_remove() - remove device memory (kill and free ZONE_DEVICE) - * - * @devmem: hmm_devmem struct use to track and manage the ZONE_DEVICE memory - * - * This will hot-unplug memory that was hotplugged by hmm_devmem_add on behalf - * of the device driver. It will free struct page and remove the resource that - * reserved the physical address range for this device memory. - */ -void hmm_devmem_remove(struct hmm_devmem *devmem) -{ - resource_size_t start, size; - struct device *device; - bool cdm = false; - - if (!devmem) - return; - - device = devmem->device; - start = devmem->resource->start; - size = resource_size(devmem->resource); - - cdm = devmem->resource->desc == IORES_DESC_DEVICE_PUBLIC_MEMORY; - hmm_devmem_ref_kill(&devmem->ref); - hmm_devmem_ref_exit(&devmem->ref); - hmm_devmem_pages_remove(devmem); - - if (!cdm) - devm_release_mem_region(device, start, size); -} -EXPORT_SYMBOL(hmm_devmem_remove); - -/* * A device driver that wants to handle multiple devices memory through a * single fake device can use hmm_device to do so. This is purely a helper * and it is not needed to make use of any HMM functionality. _

7 years

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[patch 087/167] mm, devm_memremap_pages: add MEMORY_DEVICE_PRIVATE support

by akpm＠linux-foundation.org

From: Dan Williams <dan.j.williams(a)intel.com> Subject: mm, devm_memremap_pages: add MEMORY_DEVICE_PRIVATE support In preparation for consolidating all ZONE_DEVICE enabling via devm_memremap_pages(), teach it how to handle the constraints of MEMORY_DEVICE_PRIVATE ranges. [jglisse(a)redhat.com: call move_pfn_range_to_zone for MEMORY_DEVICE_PRIVATE] Link: http://lkml.kernel.org/r/154275559036.76910.12434636179931292607.stgit@dwil… Signed-off-by: Dan Williams <dan.j.williams(a)intel.com> Reviewed-by: Jérôme Glisse <jglisse(a)redhat.com> Acked-by: Christoph Hellwig <hch(a)lst.de> Reported-by: Logan Gunthorpe <logang(a)deltatee.com> Reviewed-by: Logan Gunthorpe <logang(a)deltatee.com> Cc: Balbir Singh <bsingharora(a)gmail.com> Cc: Michal Hocko <mhocko(a)suse.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- --- a/kernel/memremap.c~mm-devm_memremap_pages-add-memory_device_private-support +++ a/kernel/memremap.c @@ -98,9 +98,15 @@ static void devm_memremap_pages_release( - align_start; mem_hotplug_begin(); - arch_remove_memory(align_start, align_size, pgmap->altmap_valid ? - &pgmap->altmap : NULL); - kasan_remove_zero_shadow(__va(align_start), align_size); + if (pgmap->type == MEMORY_DEVICE_PRIVATE) { + pfn = align_start >> PAGE_SHIFT; + __remove_pages(page_zone(pfn_to_page(pfn)), pfn, + align_size >> PAGE_SHIFT, NULL); + } else { + arch_remove_memory(align_start, align_size, + pgmap->altmap_valid ? &pgmap->altmap : NULL); + kasan_remove_zero_shadow(__va(align_start), align_size); + } mem_hotplug_done(); untrack_pfn(NULL, PHYS_PFN(align_start), align_size); @@ -187,17 +193,40 @@ void *devm_memremap_pages(struct device goto err_pfn_remap; mem_hotplug_begin(); - error = kasan_add_zero_shadow(__va(align_start), align_size); - if (error) { - mem_hotplug_done(); - goto err_kasan; + + /* + * For device private memory we call add_pages() as we only need to + * allocate and initialize struct page for the device memory. More- + * over the device memory is un-accessible thus we do not want to + * create a linear mapping for the memory like arch_add_memory() + * would do. + * + * For all other device memory types, which are accessible by + * the CPU, we do want the linear mapping and thus use + * arch_add_memory(). + */ + if (pgmap->type == MEMORY_DEVICE_PRIVATE) { + error = add_pages(nid, align_start >> PAGE_SHIFT, + align_size >> PAGE_SHIFT, NULL, false); + } else { + error = kasan_add_zero_shadow(__va(align_start), align_size); + if (error) { + mem_hotplug_done(); + goto err_kasan; + } + + error = arch_add_memory(nid, align_start, align_size, altmap, + false); + } + + if (!error) { + struct zone *zone; + + zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE]; + move_pfn_range_to_zone(zone, align_start >> PAGE_SHIFT, + align_size >> PAGE_SHIFT, altmap); } - error = arch_add_memory(nid, align_start, align_size, altmap, false); - if (!error) - move_pfn_range_to_zone(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], - align_start >> PAGE_SHIFT, - align_size >> PAGE_SHIFT, altmap); mem_hotplug_done(); if (error) goto err_add_memory; _

7 years

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[patch 086/167] mm, devm_memremap_pages: fix shutdown handling

by akpm＠linux-foundation.org

From: Dan Williams <dan.j.williams(a)intel.com> Subject: mm, devm_memremap_pages: fix shutdown handling The last step before devm_memremap_pages() returns success is to allocate a release action, devm_memremap_pages_release(), to tear the entire setup down. However, the result from devm_add_action() is not checked. Checking the error from devm_add_action() is not enough. The api currently relies on the fact that the percpu_ref it is using is killed by the time the devm_memremap_pages_release() is run. Rather than continue this awkward situation, offload the responsibility of killing the percpu_ref to devm_memremap_pages_release() directly. This allows devm_memremap_pages() to do the right thing relative to init failures and shutdown. Without this change we could fail to register the teardown of devm_memremap_pages(). The likelihood of hitting this failure is tiny as small memory allocations almost always succeed. However, the impact of the failure is large given any future reconfiguration, or disable/enable, of an nvdimm namespace will fail forever as subsequent calls to devm_memremap_pages() will fail to setup the pgmap_radix since there will be stale entries for the physical address range. An argument could be made to require that the ->kill() operation be set in the @pgmap arg rather than passed in separately. However, it helps code readability, tracking the lifetime of a given instance, to be able to grep the kill routine directly at the devm_memremap_pages() call site. Link: http://lkml.kernel.org/r/154275558526.76910.7535251937849268605.stgit@dwill… Signed-off-by: Dan Williams <dan.j.williams(a)intel.com> Fixes: e8d513483300 ("memremap: change devm_memremap_pages interface...") Reviewed-by: "Jérôme Glisse" <jglisse(a)redhat.com> Reported-by: Logan Gunthorpe <logang(a)deltatee.com> Reviewed-by: Logan Gunthorpe <logang(a)deltatee.com> Reviewed-by: Christoph Hellwig <hch(a)lst.de> Cc: Balbir Singh <bsingharora(a)gmail.com> Cc: Michal Hocko <mhocko(a)suse.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- --- a/drivers/dax/pmem.c~mm-devm_memremap_pages-fix-shutdown-handling +++ a/drivers/dax/pmem.c @@ -48,9 +48,8 @@ static void dax_pmem_percpu_exit(void *d percpu_ref_exit(ref); } -static void dax_pmem_percpu_kill(void *data) +static void dax_pmem_percpu_kill(struct percpu_ref *ref) { - struct percpu_ref *ref = data; struct dax_pmem *dax_pmem = to_dax_pmem(ref); dev_dbg(dax_pmem->dev, "trace\n"); @@ -112,17 +111,10 @@ static int dax_pmem_probe(struct device } dax_pmem->pgmap.ref = &dax_pmem->ref; + dax_pmem->pgmap.kill = dax_pmem_percpu_kill; addr = devm_memremap_pages(dev, &dax_pmem->pgmap); - if (IS_ERR(addr)) { - devm_remove_action(dev, dax_pmem_percpu_exit, &dax_pmem->ref); - percpu_ref_exit(&dax_pmem->ref); + if (IS_ERR(addr)) return PTR_ERR(addr); - } - - rc = devm_add_action_or_reset(dev, dax_pmem_percpu_kill, - &dax_pmem->ref); - if (rc) - return rc; /* adjust the dax_region resource to the start of data */ memcpy(&res, &dax_pmem->pgmap.res, sizeof(res)); --- a/drivers/nvdimm/pmem.c~mm-devm_memremap_pages-fix-shutdown-handling +++ a/drivers/nvdimm/pmem.c @@ -309,8 +309,11 @@ static void pmem_release_queue(void *q) blk_cleanup_queue(q); } -static void pmem_freeze_queue(void *q) +static void pmem_freeze_queue(struct percpu_ref *ref) { + struct request_queue *q; + + q = container_of(ref, typeof(*q), q_usage_counter); blk_freeze_queue_start(q); } @@ -402,6 +405,7 @@ static int pmem_attach_disk(struct devic pmem->pfn_flags = PFN_DEV; pmem->pgmap.ref = &q->q_usage_counter; + pmem->pgmap.kill = pmem_freeze_queue; if (is_nd_pfn(dev)) { if (setup_pagemap_fsdax(dev, &pmem->pgmap)) return -ENOMEM; @@ -427,13 +431,6 @@ static int pmem_attach_disk(struct devic memcpy(&bb_res, &nsio->res, sizeof(bb_res)); } - /* - * At release time the queue must be frozen before - * devm_memremap_pages is unwound - */ - if (devm_add_action_or_reset(dev, pmem_freeze_queue, q)) - return -ENOMEM; - if (IS_ERR(addr)) return PTR_ERR(addr); pmem->virt_addr = addr; --- a/include/linux/memremap.h~mm-devm_memremap_pages-fix-shutdown-handling +++ a/include/linux/memremap.h @@ -111,6 +111,7 @@ typedef void (*dev_page_free_t)(struct p * @altmap: pre-allocated/reserved memory for vmemmap allocations * @res: physical address range covered by @ref * @ref: reference count that pins the devm_memremap_pages() mapping + * @kill: callback to transition @ref to the dead state * @dev: host device of the mapping for debug * @data: private data pointer for page_free() * @type: memory type: see MEMORY_* in memory_hotplug.h @@ -122,6 +123,7 @@ struct dev_pagemap { bool altmap_valid; struct resource res; struct percpu_ref *ref; + void (*kill)(struct percpu_ref *ref); struct device *dev; void *data; enum memory_type type; --- a/kernel/memremap.c~mm-devm_memremap_pages-fix-shutdown-handling +++ a/kernel/memremap.c @@ -88,14 +88,10 @@ static void devm_memremap_pages_release( resource_size_t align_start, align_size; unsigned long pfn; + pgmap->kill(pgmap->ref); for_each_device_pfn(pfn, pgmap) put_page(pfn_to_page(pfn)); - if (percpu_ref_tryget_live(pgmap->ref)) { - dev_WARN(dev, "%s: page mapping is still live!\n", __func__); - percpu_ref_put(pgmap->ref); - } - /* pages are dead and unused, undo the arch mapping */ align_start = res->start & ~(SECTION_SIZE - 1); align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE) @@ -116,7 +112,7 @@ static void devm_memremap_pages_release( /** * devm_memremap_pages - remap and provide memmap backing for the given resource * @dev: hosting device for @res - * @pgmap: pointer to a struct dev_pgmap + * @pgmap: pointer to a struct dev_pagemap * * Notes: * 1/ At a minimum the res, ref and type members of @pgmap must be initialized @@ -125,11 +121,8 @@ static void devm_memremap_pages_release( * 2/ The altmap field may optionally be initialized, in which case altmap_valid * must be set to true * - * 3/ pgmap.ref must be 'live' on entry and 'dead' before devm_memunmap_pages() - * time (or devm release event). The expected order of events is that ref has - * been through percpu_ref_kill() before devm_memremap_pages_release(). The - * wait for the completion of all references being dropped and - * percpu_ref_exit() must occur after devm_memremap_pages_release(). + * 3/ pgmap->ref must be 'live' on entry and will be killed at + * devm_memremap_pages_release() time, or if this routine fails. * * 4/ res is expected to be a host memory range that could feasibly be * treated as a "System RAM" range, i.e. not a device mmio range, but @@ -145,6 +138,9 @@ void *devm_memremap_pages(struct device pgprot_t pgprot = PAGE_KERNEL; int error, nid, is_ram; + if (!pgmap->ref || !pgmap->kill) + return ERR_PTR(-EINVAL); + align_start = res->start & ~(SECTION_SIZE - 1); align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE) - align_start; @@ -170,12 +166,10 @@ void *devm_memremap_pages(struct device if (is_ram != REGION_DISJOINT) { WARN_ONCE(1, "%s attempted on %s region %pr\n", __func__, is_ram == REGION_MIXED ? "mixed" : "ram", res); - return ERR_PTR(-ENXIO); + error = -ENXIO; + goto err_array; } - if (!pgmap->ref) - return ERR_PTR(-EINVAL); - pgmap->dev = dev; error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(res->start), @@ -217,7 +211,10 @@ void *devm_memremap_pages(struct device align_size >> PAGE_SHIFT, pgmap); percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap)); - devm_add_action(dev, devm_memremap_pages_release, pgmap); + error = devm_add_action_or_reset(dev, devm_memremap_pages_release, + pgmap); + if (error) + return ERR_PTR(error); return __va(res->start); @@ -228,6 +225,7 @@ void *devm_memremap_pages(struct device err_pfn_remap: pgmap_array_delete(res); err_array: + pgmap->kill(pgmap->ref); return ERR_PTR(error); } EXPORT_SYMBOL_GPL(devm_memremap_pages); --- a/tools/testing/nvdimm/test/iomap.c~mm-devm_memremap_pages-fix-shutdown-handling +++ a/tools/testing/nvdimm/test/iomap.c @@ -104,13 +104,26 @@ void *__wrap_devm_memremap(struct device } EXPORT_SYMBOL(__wrap_devm_memremap); +static void nfit_test_kill(void *_pgmap) +{ + struct dev_pagemap *pgmap = _pgmap; + + pgmap->kill(pgmap->ref); +} + void *__wrap_devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) { resource_size_t offset = pgmap->res.start; struct nfit_test_resource *nfit_res = get_nfit_res(offset); - if (nfit_res) + if (nfit_res) { + int rc; + + rc = devm_add_action_or_reset(dev, nfit_test_kill, pgmap); + if (rc) + return ERR_PTR(rc); return nfit_res->buf + offset - nfit_res->res.start; + } return devm_memremap_pages(dev, pgmap); } EXPORT_SYMBOL_GPL(__wrap_devm_memremap_pages); _

7 years

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[patch 085/167] mm, devm_memremap_pages: kill mapping "System RAM" support

by akpm＠linux-foundation.org

From: Dan Williams <dan.j.williams(a)intel.com> Subject: mm, devm_memremap_pages: kill mapping "System RAM" support Given the fact that devm_memremap_pages() requires a percpu_ref that is torn down by devm_memremap_pages_release() the current support for mapping RAM is broken. Support for remapping "System RAM" has been broken since the beginning and there is no existing user of this this code path, so just kill the support and make it an explicit error. This cleanup also simplifies a follow-on patch to fix the error path when setting a devm release action for devm_memremap_pages_release() fails. Link: http://lkml.kernel.org/r/154275557997.76910.14689813630968180480.stgit@dwil… Signed-off-by: Dan Williams <dan.j.williams(a)intel.com> Reviewed-by: "Jérôme Glisse" <jglisse(a)redhat.com> Reviewed-by: Christoph Hellwig <hch(a)lst.de> Reviewed-by: Logan Gunthorpe <logang(a)deltatee.com> Cc: Balbir Singh <bsingharora(a)gmail.com> Cc: Michal Hocko <mhocko(a)suse.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- --- a/kernel/memremap.c~mm-devm_memremap_pages-kill-mapping-system-ram-support +++ a/kernel/memremap.c @@ -167,15 +167,12 @@ void *devm_memremap_pages(struct device is_ram = region_intersects(align_start, align_size, IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE); - if (is_ram == REGION_MIXED) { - WARN_ONCE(1, "%s attempted on mixed region %pr\n", - __func__, res); + if (is_ram != REGION_DISJOINT) { + WARN_ONCE(1, "%s attempted on %s region %pr\n", __func__, + is_ram == REGION_MIXED ? "mixed" : "ram", res); return ERR_PTR(-ENXIO); } - if (is_ram == REGION_INTERSECTS) - return __va(res->start); - if (!pgmap->ref) return ERR_PTR(-EINVAL); _

7 years

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[patch 084/167] mm, devm_memremap_pages: mark devm_memremap_pages() EXPORT_SYMBOL_GPL

by akpm＠linux-foundation.org

From: Dan Williams <dan.j.williams(a)intel.com> Subject: mm, devm_memremap_pages: mark devm_memremap_pages() EXPORT_SYMBOL_GPL devm_memremap_pages() is a facility that can create struct page entries for any arbitrary range and give drivers the ability to subvert core aspects of page management. Specifically the facility is tightly integrated with the kernel's memory hotplug functionality. It injects an altmap argument deep into the architecture specific vmemmap implementation to allow allocating from specific reserved pages, and it has Linux specific assumptions about page structure reference counting relative to get_user_pages() and get_user_pages_fast(). It was an oversight and a mistake that this was not marked EXPORT_SYMBOL_GPL from the outset. Again, devm_memremap_pagex() exposes and relies upon core kernel internal assumptions and will continue to evolve along with 'struct page', memory hotplug, and support for new memory types / topologies. Only an in-kernel GPL-only driver is expected to keep up with this ongoing evolution. This interface, and functionality derived from this interface, is not suitable for kernel-external drivers. Link: http://lkml.kernel.org/r/154275557457.76910.16923571232582744134.stgit@dwil… Signed-off-by: Dan Williams <dan.j.williams(a)intel.com> Reviewed-by: Christoph Hellwig <hch(a)lst.de> Acked-by: Michal Hocko <mhocko(a)suse.com> Cc: "Jérôme Glisse" <jglisse(a)redhat.com> Cc: Balbir Singh <bsingharora(a)gmail.com> Cc: Logan Gunthorpe <logang(a)deltatee.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- --- a/kernel/memremap.c~mm-devm_memremap_pages-mark-devm_memremap_pages-export_symbol_gpl +++ a/kernel/memremap.c @@ -233,7 +233,7 @@ void *devm_memremap_pages(struct device err_array: return ERR_PTR(error); } -EXPORT_SYMBOL(devm_memremap_pages); +EXPORT_SYMBOL_GPL(devm_memremap_pages); unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) { --- a/tools/testing/nvdimm/test/iomap.c~mm-devm_memremap_pages-mark-devm_memremap_pages-export_symbol_gpl +++ a/tools/testing/nvdimm/test/iomap.c @@ -113,7 +113,7 @@ void *__wrap_devm_memremap_pages(struct return nfit_res->buf + offset - nfit_res->res.start; return devm_memremap_pages(dev, pgmap); } -EXPORT_SYMBOL(__wrap_devm_memremap_pages); +EXPORT_SYMBOL_GPL(__wrap_devm_memremap_pages); pfn_t __wrap_phys_to_pfn_t(phys_addr_t addr, unsigned long flags) { _

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[folded-merged] hugetlbfs-use-i_mmap_rwsem-to-fix-page-fault-truncate-race-v3.patch removed from -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: hugetlbfs-use-i_mmap_rwsem-to-fix-page-fault-truncate-race-v3 has been removed from the -mm tree. Its filename was hugetlbfs-use-i_mmap_rwsem-to-fix-page-fault-truncate-race-v3.patch This patch was dropped because it was folded into hugetlbfs-use-i_mmap_rwsem-to-fix-page-fault-truncate-race.patch ------------------------------------------------------ From: Mike Kravetz <mike.kravetz(a)oracle.com> Subject: hugetlbfs-use-i_mmap_rwsem-to-fix-page-fault-truncate-race-v3 Incorporated suggestions from Kirill. Code change to hold i_mmap_rwsem for duration of copy in copy_hugetlb_page_range. Took i_mmap_rwsem in hugetlbfs_evict_inode to be consistent with other callers. Other changes were to documentation/comments. Link: http://lkml.kernel.org/r/20181222223013.22193-3-mike.kravetz@oracle.com Cc: <stable(a)vger.kernel.org> Fixes: ebed4bfc8da8 ("hugetlb: fix absurd HugePages_Rsvd") Signed-off-by: Mike Kravetz <mike.kravetz(a)oracle.com> Cc: Andrea Arcangeli <aarcange(a)redhat.com> Cc: "Aneesh Kumar K . V" <aneesh.kumar(a)linux.vnet.ibm.com> Cc: Davidlohr Bueso <dave(a)stgolabs.net> Cc: Hugh Dickins <hughd(a)google.com> Cc: "Kirill A . Shutemov" <kirill.shutemov(a)linux.intel.com> Cc: Michal Hocko <mhocko(a)kernel.org> Cc: Naoya Horiguchi <n-horiguchi(a)ah.jp.nec.com> Cc: Prakash Sangappa <prakash.sangappa(a)oracle.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- --- a/fs/hugetlbfs/inode.c~hugetlbfs-use-i_mmap_rwsem-to-fix-page-fault-truncate-race-v3 +++ a/fs/hugetlbfs/inode.c @@ -462,9 +462,20 @@ static void remove_inode_hugepages(struc static void hugetlbfs_evict_inode(struct inode *inode) { + struct address_space *mapping = inode->i_mapping; struct resv_map *resv_map; + /* + * The vfs layer guarantees that there are no other users of this + * inode. Therefore, it would be safe to call remove_inode_hugepages + * without holding i_mmap_rwsem. We acquire and hold here to be + * consistent with other callers. Since there will be no contention + * on the semaphore, overhead is negligible. + */ + i_mmap_lock_write(mapping); remove_inode_hugepages(inode, 0, LLONG_MAX); + i_mmap_unlock_write(mapping); + resv_map = (struct resv_map *)inode->i_mapping->private_data; /* root inode doesn't have the resv_map, so we should check it */ if (resv_map) _ Patches currently in -mm which might be from mike.kravetz(a)oracle.com are hugetlbfs-use-i_mmap_rwsem-for-more-pmd-sharing-synchronization.patch hugetlbfs-use-i_mmap_rwsem-to-fix-page-fault-truncate-race.patch

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+ hugetlbfs-use-i_mmap_rwsem-to-fix-page-fault-truncate-race-v3.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: hugetlbfs-use-i_mmap_rwsem-to-fix-page-fault-truncate-race-v3 has been added to the -mm tree. Its filename is hugetlbfs-use-i_mmap_rwsem-to-fix-page-fault-truncate-race-v3.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/hugetlbfs-use-i_mmap_rwsem-to-fix-… and later at http://ozlabs.org/~akpm/mmotm/broken-out/hugetlbfs-use-i_mmap_rwsem-to-fix-… Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Mike Kravetz <mike.kravetz(a)oracle.com> Subject: hugetlbfs-use-i_mmap_rwsem-to-fix-page-fault-truncate-race-v3 Incorporated suggestions from Kirill. Code change to hold i_mmap_rwsem for duration of copy in copy_hugetlb_page_range. Took i_mmap_rwsem in hugetlbfs_evict_inode to be consistent with other callers. Other changes were to documentation/comments. Link: http://lkml.kernel.org/r/20181222223013.22193-3-mike.kravetz@oracle.com Cc: <stable(a)vger.kernel.org> Fixes: ebed4bfc8da8 ("hugetlb: fix absurd HugePages_Rsvd") Signed-off-by: Mike Kravetz <mike.kravetz(a)oracle.com> Cc: Andrea Arcangeli <aarcange(a)redhat.com> Cc: "Aneesh Kumar K . V" <aneesh.kumar(a)linux.vnet.ibm.com> Cc: Davidlohr Bueso <dave(a)stgolabs.net> Cc: Hugh Dickins <hughd(a)google.com> Cc: "Kirill A . Shutemov" <kirill.shutemov(a)linux.intel.com> Cc: Michal Hocko <mhocko(a)kernel.org> Cc: Naoya Horiguchi <n-horiguchi(a)ah.jp.nec.com> Cc: Prakash Sangappa <prakash.sangappa(a)oracle.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- --- a/fs/hugetlbfs/inode.c~hugetlbfs-use-i_mmap_rwsem-to-fix-page-fault-truncate-race-v3 +++ a/fs/hugetlbfs/inode.c @@ -462,9 +462,20 @@ static void remove_inode_hugepages(struc static void hugetlbfs_evict_inode(struct inode *inode) { + struct address_space *mapping = inode->i_mapping; struct resv_map *resv_map; + /* + * The vfs layer guarantees that there are no other users of this + * inode. Therefore, it would be safe to call remove_inode_hugepages + * without holding i_mmap_rwsem. We acquire and hold here to be + * consistent with other callers. Since there will be no contention + * on the semaphore, overhead is negligible. + */ + i_mmap_lock_write(mapping); remove_inode_hugepages(inode, 0, LLONG_MAX); + i_mmap_unlock_write(mapping); + resv_map = (struct resv_map *)inode->i_mapping->private_data; /* root inode doesn't have the resv_map, so we should check it */ if (resv_map) _ Patches currently in -mm which might be from mike.kravetz(a)oracle.com are hugetlbfs-use-i_mmap_rwsem-for-more-pmd-sharing-synchronization.patch hugetlbfs-use-i_mmap_rwsem-for-more-pmd-sharing-synchronization-fix.patch hugetlbfs-use-i_mmap_rwsem-to-fix-page-fault-truncate-race.patch hugetlbfs-use-i_mmap_rwsem-to-fix-page-fault-truncate-race-v3.patch

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bug report: hugetlbfs: use i_mmap_rwsem for more pmd sharing, synchronization

by Colin Ian King

Hi, Static analysis with CoverityScan on linux-next detected a potential null pointer dereference with the following commit: >From d8a1051ed4ba55679ef24e838a1942c9c40f0a14 Mon Sep 17 00:00:00 2001 From: Mike Kravetz <mike.kravetz(a)oracle.com> Date: Sat, 22 Dec 2018 10:55:57 +1100 Subject: [PATCH] hugetlbfs: use i_mmap_rwsem for more pmd sharing The earlier check implies that "mapping" may be a null pointer: var_compare_op: Comparing mapping to null implies that mapping might be null. 1008 if (!(flags & MF_MUST_KILL) && !PageDirty(hpage) && mapping && 1009 mapping_cap_writeback_dirty(mapping)) { ..however later "mapper" is dereferenced when it may be potentially null: 1034 /* 1035 * For hugetlb pages, try_to_unmap could potentially call 1036 * huge_pmd_unshare. Because of this, take semaphore in 1037 * write mode here and set TTU_RMAP_LOCKED to indicate we 1038 * have taken the lock at this higer level. 1039 */ CID 1476097 (#1 of 1): Dereference after null check (FORWARD_NULL) var_deref_model: Passing null pointer mapping to i_mmap_lock_write, which dereferences it. 1040 i_mmap_lock_write(mapping); 1041 unmap_success = try_to_unmap(hpage, ttu|TTU_RMAP_LOCKED); 1042 i_mmap_unlock_write(mapping); Colin

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+ memcg-oom-notify-on-oom-killer-invocation-from-the-charge-path.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: memcg, oom: notify on oom killer invocation from the charge path has been added to the -mm tree. Its filename is memcg-oom-notify-on-oom-killer-invocation-from-the-charge-path.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/memcg-oom-notify-on-oom-killer-inv… and later at http://ozlabs.org/~akpm/mmotm/broken-out/memcg-oom-notify-on-oom-killer-inv… Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Michal Hocko <mhocko(a)suse.com> Subject: memcg, oom: notify on oom killer invocation from the charge path Burt Holzman has noticed that memcg v1 doesn't notify about OOM events via eventfd anymore. The reason is that 29ef680ae7c2 ("memcg, oom: move out_of_memory back to the charge path") has moved the oom handling back to the charge path. While doing so the notification was left behind in mem_cgroup_oom_synchronize. Fix the issue by replicating the oom hierarchy locking and the notification. Link: http://lkml.kernel.org/r/20181224091107.18354-1-mhocko@kernel.org Fixes: 29ef680ae7c2 ("memcg, oom: move out_of_memory back to the charge path") Signed-off-by: Michal Hocko <mhocko(a)suse.com> Reported-by: Burt Holzman <burt(a)fnal.gov> Acked-by: Johannes Weiner <hannes(a)cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev(a)gmail.com Cc: <stable(a)vger.kernel.org> [4.19+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- --- a/mm/memcontrol.c~memcg-oom-notify-on-oom-killer-invocation-from-the-charge-path +++ a/mm/memcontrol.c @@ -1673,6 +1673,9 @@ enum oom_status { static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order) { + enum oom_status ret; + bool locked; + if (order > PAGE_ALLOC_COSTLY_ORDER) return OOM_SKIPPED; @@ -1707,10 +1710,23 @@ static enum oom_status mem_cgroup_oom(st return OOM_ASYNC; } + mem_cgroup_mark_under_oom(memcg); + + locked = mem_cgroup_oom_trylock(memcg); + + if (locked) + mem_cgroup_oom_notify(memcg); + + mem_cgroup_unmark_under_oom(memcg); if (mem_cgroup_out_of_memory(memcg, mask, order)) - return OOM_SUCCESS; + ret = OOM_SUCCESS; + else + ret = OOM_FAILED; + + if (locked) + mem_cgroup_oom_unlock(memcg); - return OOM_FAILED; + return ret; } /** _ Patches currently in -mm which might be from mhocko(a)suse.com are mm-memcg-fix-reclaim-deadlock-with-writeback.patch mm-print-more-information-about-mapping-in-__dump_page.patch mm-lower-the-printk-loglevel-for-__dump_page-messages.patch mm-memory_hotplug-drop-pointless-block-alignment-checks-from-__offline_pages.patch mm-memory_hotplug-print-reason-for-the-offlining-failure.patch mm-memory_hotplug-be-more-verbose-for-memory-offline-failures.patch mm-memory_hotplug-be-more-verbose-for-memory-offline-failures-update.patch mm-only-report-isolation-failures-when-offlining-memory.patch mm-memory_hotplug-do-not-clear-numa_node-association-after-hot_remove.patch hwpoison-memory_hotplug-allow-hwpoisoned-pages-to-be-offlined.patch mm-proc-be-more-verbose-about-unstable-vma-flags-in-proc-pid-smaps.patch mm-thp-proc-report-thp-eligibility-for-each-vma.patch mm-proc-report-pr_set_thp_disable-in-proc.patch mm-memory_hotplug-try-to-migrate-full-pfn-range.patch mm-memory_hotplug-deobfuscate-migration-part-of-offlining.patch mm-fault_around-do-not-take-a-reference-to-a-locked-page.patch memory_hotplug-add-missing-newlines-to-debugging-output.patch memcg-oom-notify-on-oom-killer-invocation-from-the-charge-path.patch

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4.19.5 and later has tons of false messages "BUG: non-zero pgtables_bytes on freeing mm: -16384"

by Christian Borntraeger

Martin, Right now you get a message "BUG: non-zero pgtables_bytes on freeing mm: -16384" for EVERY process that exits in 4.19.5 and later. bisect points to commit 4136161d676a93fc8df6bdb80d720c15522d6c24 Author: Martin Schwidefsky <schwidefsky(a)de.ibm.com> Date: Mon Oct 15 11:09:16 2018 +0200 s390/mm: fix mis-accounting of pgtable_bytes [ Upstream commit e12e4044aede97974f2222eb7f0ed726a5179a32 ] Turns out that this patch requires several dependencies so the autoselection of this patch was missing that. Can we either revert this patch or add the dependencies? Christian

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