Thread (22 messages) 22 messages, 5 authors, 2025-05-15
STALE431d

[PATCH net-next v4 13/15] rds: Disable only bottom halves in rds_page_remainder_alloc()

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: 2025-05-12 09:27:48
Also in: linux-rdma, linux-rt-devel
Subsystem: networking [general], rds - reliable datagram sockets, the rest · Maintainers: "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Allison Henderson, Linus Torvalds

rds_page_remainder_alloc() is invoked from a preemptible context or a
tasklet. There is no need to disable interrupts for locking.

Use local_bh_disable() instead of local_irq_save() for locking.

Cc: Allison Henderson <redacted>
Cc: linux-rdma@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 net/rds/page.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/net/rds/page.c b/net/rds/page.c
index 7cc57e098ddb9..e0dd4f62ea47a 100644
--- a/net/rds/page.c
+++ b/net/rds/page.c
@@ -69,7 +69,6 @@ int rds_page_remainder_alloc(struct scatterlist *scat, unsigned long bytes,
 			     gfp_t gfp)
 {
 	struct rds_page_remainder *rem;
-	unsigned long flags;
 	struct page *page;
 	int ret;
 
@@ -88,7 +87,7 @@ int rds_page_remainder_alloc(struct scatterlist *scat, unsigned long bytes,
 	}
 
 	rem = &per_cpu(rds_page_remainders, get_cpu());
-	local_irq_save(flags);
+	local_bh_disable();
 
 	while (1) {
 		/* avoid a tiny region getting stuck by tossing it */
@@ -116,13 +115,13 @@ int rds_page_remainder_alloc(struct scatterlist *scat, unsigned long bytes,
 		}
 
 		/* alloc if there is nothing for us to use */
-		local_irq_restore(flags);
+		local_bh_enable();
 		put_cpu();
 
 		page = alloc_page(gfp);
 
 		rem = &per_cpu(rds_page_remainders, get_cpu());
-		local_irq_save(flags);
+		local_bh_disable();
 
 		if (!page) {
 			ret = -ENOMEM;
@@ -140,7 +139,7 @@ int rds_page_remainder_alloc(struct scatterlist *scat, unsigned long bytes,
 		rem->r_offset = 0;
 	}
 
-	local_irq_restore(flags);
+	local_bh_enable();
 	put_cpu();
 out:
 	rdsdebug("bytes %lu ret %d %p %u %u\n", bytes, ret,
-- 
2.49.0
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