+ lib-percpu_idac-dont-do-alloc-from-per-cpu-list-if-there-is-none.patch added to -mm tree

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The patch titled
     Subject: lib/percpu_ida.c: don't do alloc from per-CPU list if there is none
has been added to the -mm tree.  Its filename is
     lib-percpu_idac-dont-do-alloc-from-per-cpu-list-if-there-is-none.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/lib-percpu_idac-dont-do-alloc-from-per-cpu-list-if-there-is-none.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/lib-percpu_idac-dont-do-alloc-from-per-cpu-list-if-there-is-none.patch

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------------------------------------------------------
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;
_

Patches currently in -mm which might be from bigeasy@xxxxxxxxxxxxx are

lib-percpu_idac-dont-do-alloc-from-per-cpu-list-if-there-is-none.patch

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