This is a note to let you know that I've just added the patch titled
net: page_pool: use in_softirq() instead
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:
net-page_pool-use-in_softirq-instead.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 f7d31332f760cbbbccb887894f6a0e7fd7001de0
Author: Qingfang DENG <qingfang.deng@xxxxxxxxxxxxxxx>
Date: Fri Feb 3 09:16:11 2023 +0800
net: page_pool: use in_softirq() instead
[ Upstream commit 542bcea4be866b14b3a5c8e90773329066656c43 ]
We use BH context only for synchronization, so we don't care if it's
actually serving softirq or not.
As a side node, in case of threaded NAPI, in_serving_softirq() will
return false because it's in process context with BH off, making
page_pool_recycle_in_cache() unreachable.
Signed-off-by: Qingfang DENG <qingfang.deng@xxxxxxxxxxxxxxx>
Tested-by: Felix Fietkau <nbd@xxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Stable-dep-of: 368d3cb406cd ("page_pool: fix inconsistency for page_pool_ring_[un]lock()")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/net/page_pool.h b/include/net/page_pool.h
index a4082406a0039..80d987419436e 100644
--- a/include/net/page_pool.h
+++ b/include/net/page_pool.h
@@ -285,7 +285,7 @@ static inline void page_pool_nid_changed(struct page_pool *pool, int new_nid)
static inline void page_pool_ring_lock(struct page_pool *pool)
__acquires(&pool->ring.producer_lock)
{
- if (in_serving_softirq())
+ if (in_softirq())
spin_lock(&pool->ring.producer_lock);
else
spin_lock_bh(&pool->ring.producer_lock);
@@ -294,7 +294,7 @@ static inline void page_pool_ring_lock(struct page_pool *pool)
static inline void page_pool_ring_unlock(struct page_pool *pool)
__releases(&pool->ring.producer_lock)
{
- if (in_serving_softirq())
+ if (in_softirq())
spin_unlock(&pool->ring.producer_lock);
else
spin_unlock_bh(&pool->ring.producer_lock);
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 1a6978427d6c8..1d520fa1b98a8 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -390,8 +390,8 @@ static void page_pool_return_page(struct page_pool *pool, struct page *page)
static bool page_pool_recycle_in_ring(struct page_pool *pool, struct page *page)
{
int ret;
- /* BH protection not needed if current is serving softirq */
- if (in_serving_softirq())
+ /* BH protection not needed if current is softirq */
+ if (in_softirq())
ret = ptr_ring_produce(&pool->ring, page);
else
ret = ptr_ring_produce_bh(&pool->ring, page);
@@ -446,7 +446,7 @@ __page_pool_put_page(struct page_pool *pool, struct page *page,
page_pool_dma_sync_for_device(pool, page,
dma_sync_size);
- if (allow_direct && in_serving_softirq() &&
+ if (allow_direct && in_softirq() &&
page_pool_recycle_in_cache(page, pool))
return NULL;
