Patch "net: page_pool: use in_softirq() instead" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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 6.1-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-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit fd295408c719ed8b6b4595392c12e6575fedbfe0
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 813c93499f201..34bf531ffc8d6 100644
--- a/include/net/page_pool.h
+++ b/include/net/page_pool.h
@@ -386,7 +386,7 @@ 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);
@@ -395,7 +395,7 @@ 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 9b203d8660e47..193c187998650 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -511,8 +511,8 @@ 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);
@@ -570,7 +570,7 @@ __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;