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([2a02:3037:66c:7629:ce5b:4236:52ab:dfe8]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48a525a0b1asm173524195e9.2.2026.04.25.01.58.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 25 Apr 2026 01:58:46 -0700 (PDT) From: Abd-Alrhman Masalkhi To: song@kernel.org, yukuai@fnnas.com Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, Abd-Alrhman Masalkhi Subject: [PATCH] md: skip redundant raid_disks update when value is unchanged Date: Sat, 25 Apr 2026 10:58:43 +0200 Message-ID: <20260425085843.3725-1-abd.masalkhi@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Calling update_raid_disks() with the same value as the current one can trigger unnecessary work. For example, RAID1 will reallocate resources such as the mempool for r1bio. Signed-off-by: Abd-Alrhman Masalkhi --- It returns -EINVAL for the same value. If silent success is preferred instead, please let me know so I adjust its behavior. --- drivers/md/md.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 0e55639211f2..cb66c4ebbafa 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -4409,9 +4409,12 @@ raid_disks_store(struct mddev *mddev, const char *bu= f, size_t len) err =3D mddev_suspend_and_lock(mddev); if (err) return err; - if (mddev->pers) - err =3D update_raid_disks(mddev, n); - else if (mddev->reshape_position !=3D MaxSector) { + if (mddev->pers) { + if (n !=3D mddev->raid_disks) + err =3D update_raid_disks(mddev, n); + else + err =3D -EINVAL; + } else if (mddev->reshape_position !=3D MaxSector) { struct md_rdev *rdev; int olddisks =3D mddev->raid_disks - mddev->delta_disks; =20 --=20 2.43.0