The patch below does not apply to the 6.1-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@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-6.1.y git checkout FETCH_HEAD git cherry-pick -x 368d3cb406cdd074d1df2ad9ec06d1bfcb664882 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023052820-treachery-paper-0d3a@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

368d3cb406cd ("page_pool: fix inconsistency for page_pool_ring_[un]lock()") 542bcea4be86 ("net: page_pool: use in_softirq() instead")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 368d3cb406cdd074d1df2ad9ec06d1bfcb664882 Mon Sep 17 00:00:00 2001 From: Yunsheng Lin linyunsheng@huawei.com Date: Mon, 22 May 2023 11:17:14 +0800 Subject: [PATCH] page_pool: fix inconsistency for page_pool_ring_[un]lock()

page_pool_ring_[un]lock() use in_softirq() to decide which spin lock variant to use, and when they are called in the context with in_softirq() being false, spin_lock_bh() is called in page_pool_ring_lock() while spin_unlock() is called in page_pool_ring_unlock(), because spin_lock_bh() has disabled the softirq in page_pool_ring_lock(), which causes inconsistency for spin lock pair calling.

This patch fixes it by returning in_softirq state from page_pool_producer_lock(), and use it to decide which spin lock variant to use in page_pool_producer_unlock().

As pool->ring has both producer and consumer lock, so rename it to page_pool_producer_[un]lock() to reflect the actual usage. Also move them to page_pool.c as they are only used there, and remove the 'inline' as the compiler may have better idea to do inlining or not.

Fixes: 7886244736a4 ("net: page_pool: Add bulk support for ptr_ring") Signed-off-by: Yunsheng Lin linyunsheng@huawei.com Acked-by: Jesper Dangaard Brouer brouer@redhat.com Acked-by: Ilias Apalodimas ilias.apalodimas@linaro.org Link: https://lore.kernel.org/r/20230522031714.5089-1-linyunsheng@huawei.com Signed-off-by: Jakub Kicinski kuba@kernel.org

diff --git a/include/net/page_pool.h b/include/net/page_pool.h index c8ec2f34722b..126f9e294389 100644 --- a/include/net/page_pool.h +++ b/include/net/page_pool.h @@ -399,22 +399,4 @@ static inline void page_pool_nid_changed(struct page_pool *pool, int new_nid) page_pool_update_nid(pool, new_nid); }

-static inline void page_pool_ring_lock(struct page_pool *pool) - __acquires(&pool->ring.producer_lock) -{ - if (in_softirq()) - spin_lock(&pool->ring.producer_lock); - else - spin_lock_bh(&pool->ring.producer_lock); -} - -static inline void page_pool_ring_unlock(struct page_pool *pool) - __releases(&pool->ring.producer_lock) -{ - if (in_softirq()) - spin_unlock(&pool->ring.producer_lock); - else - spin_unlock_bh(&pool->ring.producer_lock); -} - #endif /* _NET_PAGE_POOL_H */ diff --git a/net/core/page_pool.c b/net/core/page_pool.c index e212e9d7edcb..a3e12a61d456 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -134,6 +134,29 @@ EXPORT_SYMBOL(page_pool_ethtool_stats_get); #define recycle_stat_add(pool, __stat, val) #endif

+static bool page_pool_producer_lock(struct page_pool *pool) + __acquires(&pool->ring.producer_lock) +{ + bool in_softirq = in_softirq(); + + if (in_softirq) + spin_lock(&pool->ring.producer_lock); + else + spin_lock_bh(&pool->ring.producer_lock); + + return in_softirq; +} + +static void page_pool_producer_unlock(struct page_pool *pool, + bool in_softirq) + __releases(&pool->ring.producer_lock) +{ + if (in_softirq) + spin_unlock(&pool->ring.producer_lock); + else + spin_unlock_bh(&pool->ring.producer_lock); +} + static int page_pool_init(struct page_pool *pool, const struct page_pool_params *params) { @@ -617,6 +640,7 @@ void page_pool_put_page_bulk(struct page_pool *pool, void **data, int count) { int i, bulk_len = 0; + bool in_softirq;

for (i = 0; i < count; i++) { struct page *page = virt_to_head_page(data[i]); @@ -635,7 +659,7 @@ void page_pool_put_page_bulk(struct page_pool *pool, void **data, return;

/* Bulk producer into ptr_ring page_pool cache */ - page_pool_ring_lock(pool); + in_softirq = page_pool_producer_lock(pool); for (i = 0; i < bulk_len; i++) { if (__ptr_ring_produce(&pool->ring, data[i])) { /* ring full */ @@ -644,7 +668,7 @@ void page_pool_put_page_bulk(struct page_pool *pool, void **data, } } recycle_stat_add(pool, ring, i); - page_pool_ring_unlock(pool); + page_pool_producer_unlock(pool, in_softirq);

/* Hopefully all pages was return into ptr_ring */ if (likely(i == bulk_len))