From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Subject: lib/percpu_ida.c: don't do alloc from per-CPU list if there is none
In 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@xxxxxxxxxxxxx
Fixes: 804209d8a009 ("lib/percpu_ida.c: use _irqsave() instead of local_irq_save() + spin_lock")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Reported-by: David Disseldorp <ddiss@xxxxxxx>
Tested-by: David Disseldorp <ddiss@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Cc: Shaohua Li <shli@xxxxxx>
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
diff -puN lib/percpu_ida.c~lib-percpu_idac-dont-do-alloc-from-per-cpu-list-if-there-is-none lib/percpu_ida.c
--- a/lib/percpu_ida.c~lib-percpu_idac-dont-do-alloc-from-per-cpu-list-if-there-is-none
+++ a/lib/percpu_ida.c
@@ -141,7 +141,7 @@ int percpu_ida_alloc(struct percpu_ida *
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;
_
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