This is a note to let you know that I've just added the patch titled
page_pool: fix inconsistency for page_pool_ring_[un]lock()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
page_pool-fix-inconsistency-for-page_pool_ring_-un-l.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 90cd21baba9a4336765bccf5f9049d7bf45de7df
Author: Yunsheng Lin <linyunsheng@xxxxxxxxxx>
Date: Mon May 22 11:17:14 2023 +0800
page_pool: fix inconsistency for page_pool_ring_[un]lock()
[ Upstream commit 368d3cb406cdd074d1df2ad9ec06d1bfcb664882 ]
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@xxxxxxxxxx>
Acked-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Acked-by: Ilias Apalodimas <ilias.apalodimas@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230522031714.5089-1-linyunsheng@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/net/page_pool.h b/include/net/page_pool.h
index 80d987419436e..edcc22605842e 100644
--- a/include/net/page_pool.h
+++ b/include/net/page_pool.h
@@ -282,22 +282,4 @@ 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 1d520fa1b98a8..069d6ba0e33fb 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -26,6 +26,29 @@
#define BIAS_MAX LONG_MAX
+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)
{
@@ -489,6 +512,7 @@ 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]);
@@ -503,12 +527,12 @@ 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]))
break; /* ring full */
}
- 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))
