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 6.3-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_lock.patch
and it can be found in the queue-6.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 368d3cb406cdd074d1df2ad9ec06d1bfcb664882 Mon Sep 17 00:00:00 2001
From: Yunsheng Lin <linyunsheng@xxxxxxxxxx>
Date: Mon, 22 May 2023 11:17:14 +0800
Subject: page_pool: fix inconsistency for page_pool_ring_[un]lock()
From: Yunsheng Lin <linyunsheng@xxxxxxxxxx>
commit 368d3cb406cdd074d1df2ad9ec06d1bfcb664882 upstream.
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: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/net/page_pool.h | 18 ------------------
net/core/page_pool.c | 28 ++++++++++++++++++++++++++--
2 files changed, 26 insertions(+), 20 deletions(-)
--- a/include/net/page_pool.h
+++ b/include/net/page_pool.h
@@ -393,22 +393,4 @@ static inline void page_pool_nid_changed
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 */
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -133,6 +133,29 @@ EXPORT_SYMBOL(page_pool_ethtool_stats_ge
#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)
{
@@ -615,6 +638,7 @@ void page_pool_put_page_bulk(struct page
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]);
@@ -633,7 +657,7 @@ void page_pool_put_page_bulk(struct page
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 */
@@ -642,7 +666,7 @@ void page_pool_put_page_bulk(struct page
}
}
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))
Patches currently in stable-queue which might be from linyunsheng@xxxxxxxxxx are
queue-6.3/page_pool-fix-inconsistency-for-page_pool_ring_lock.patch
