[merged mm-nonmm-stable] aio-use-atomic_try_cmpxchg-in-__get_reqs_available.patch removed from -mm tree

[merged mm-nonmm-stable] aio-use-atomic_try_cmpxchg-in-__get_reqs_available.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: aio: use atomic_try_cmpxchg in __get_reqs_available
has been removed from the -mm tree.  Its filename was
     aio-use-atomic_try_cmpxchg-in-__get_reqs_available.patch

This patch was dropped because it was merged into the mm-nonmm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Uros Bizjak <ubizjak@gmail.com>
Subject: aio: use atomic_try_cmpxchg in __get_reqs_available
Date: Thu, 14 Jul 2022 18:48:51 +0200

Use atomic_try_cmpxchg instead of atomic_cmpxchg (*ptr, old, new) == old
in __get_reqs_available.  x86 CMPXCHG instruction returns success in ZF
flag, so this change saves a compare after cmpxchg (and related move
instruction in front of cmpxchg).

Also, atomic_try_cmpxchg implicitly assigns old *ptr value to "old" when
cmpxchg fails, enabling further code simplifications.

No functional change intended.

Link: https://lkml.kernel.org/r/20220714164851.3055-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/aio.c |    9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

--- a/fs/aio.c~aio-use-atomic_try_cmpxchg-in-__get_reqs_available
+++ a/fs/aio.c
@@ -951,16 +951,13 @@ static bool __get_reqs_available(struct
 	local_irq_save(flags);
 	kcpu = this_cpu_ptr(ctx->cpu);
 	if (!kcpu->reqs_available) {
-		int old, avail = atomic_read(&ctx->reqs_available);
+		int avail = atomic_read(&ctx->reqs_available);
 
 		do {
 			if (avail < ctx->req_batch)
 				goto out;
-
-			old = avail;
-			avail = atomic_cmpxchg(&ctx->reqs_available,
-					       avail, avail - ctx->req_batch);
-		} while (avail != old);
+		} while (!atomic_try_cmpxchg(&ctx->reqs_available,
+					     &avail, avail - ctx->req_batch));
 
 		kcpu->reqs_available += ctx->req_batch;
 	}
_

Patches currently in -mm which might be from ubizjak@gmail.com are