From 4bb6e96ab808f88d746343637f0cc2243b527da5 Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Wed, 27 Jun 2018 23:26:01 -0700
Subject: [PATCH] lib/percpu_ida.c: don't do alloc from per-CPU list if there
is none
In commit 804209d8a009 ("lib/percpu_ida.c: use _irqsave() instead of
local_irq_save() + spin_lock") I inlined alloc_local_tag() and mixed up
the >= check from percpu_ida_alloc() with the one in alloc_local_tag().
Don't alloc from per-CPU freelist if ->nr_free is zero.
Link: http://lkml.kernel.org/r/20180613075830.c3zeva52fuj6fxxv@linutronix.de
Fixes: 804209d8a009 ("lib/percpu_ida.c: use _irqsave() instead of local_irq_save() + spin_lock")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reported-by: David Disseldorp <ddiss@suse.de>
Tested-by: David Disseldorp <ddiss@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Cc: Shaohua Li <shli@fb.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
lib/percpu_ida.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/percpu_ida.c b/lib/percpu_ida.c
index 9bbd9c5d375a..beb14839b41a 100644
--- a/lib/percpu_ida.c
+++ b/lib/percpu_ida.c
@@ -141,7 +141,7 @@ int percpu_ida_alloc(struct percpu_ida *pool, int state)
spin_lock_irqsave(&tags->lock, flags);
/* Fastpath */
- if (likely(tags->nr_free >= 0)) {
+ if (likely(tags->nr_free)) {
tag = tags->freelist[--tags->nr_free];
spin_unlock_irqrestore(&tags->lock, flags);
return tag;
--
GitLab