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Wed, 27 Aug 2025 21:31:07 +0000 (UTC) Received: from bvanassche.mtv.corp.google.com (unknown [104.135.204.82]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bvanassche@acm.org) by 004.mia.mailroute.net (Postfix) with ESMTPSA id 4cByPy6FH4zm0yV7; Wed, 27 Aug 2025 21:31:02 +0000 (UTC) From: Bart Van Assche To: Jens Axboe Cc: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, Christoph Hellwig , Damien Le Moal , Bart Van Assche Subject: [PATCH v24 13/18] null_blk: Add the preserves_write_order attribute Date: Wed, 27 Aug 2025 14:29:32 -0700 Message-ID: <20250827212937.2759348-14-bvanassche@acm.org> X-Mailer: git-send-email 2.51.0.318.gd7df087d1a-goog In-Reply-To: <20250827212937.2759348-1-bvanassche@acm.org> References: <20250827212937.2759348-1-bvanassche@acm.org> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Support configuring the BLK_FEAT_ORDERED_HWQ flag in the null_blk driver = to make it easier to test write pipelining Cc: Damien Le Moal Cc: Christoph Hellwig Signed-off-by: Bart Van Assche --- drivers/block/null_blk/main.c | 4 ++++ drivers/block/null_blk/null_blk.h | 1 + 2 files changed, 5 insertions(+) diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.= c index 91642c9a3b29..86d72979d899 100644 --- a/drivers/block/null_blk/main.c +++ b/drivers/block/null_blk/main.c @@ -475,6 +475,7 @@ NULLB_DEVICE_ATTR(fua, bool, NULL); NULLB_DEVICE_ATTR(rotational, bool, NULL); NULLB_DEVICE_ATTR(badblocks_once, bool, NULL); NULLB_DEVICE_ATTR(badblocks_partial_io, bool, NULL); +NULLB_DEVICE_ATTR(preserves_write_order, bool, NULL); =20 static ssize_t nullb_device_power_show(struct config_item *item, char *p= age) { @@ -613,6 +614,7 @@ static struct configfs_attribute *nullb_device_attrs[= ] =3D { &nullb_device_attr_no_sched, &nullb_device_attr_poll_queues, &nullb_device_attr_power, + &nullb_device_attr_preserves_write_order, &nullb_device_attr_queue_mode, &nullb_device_attr_rotational, &nullb_device_attr_shared_tag_bitmap, @@ -1979,6 +1981,8 @@ static int null_add_dev(struct nullb_device *dev) if (dev->virt_boundary) lim.virt_boundary_mask =3D PAGE_SIZE - 1; null_config_discard(nullb, &lim); + if (dev->preserves_write_order) + lim.features |=3D BLK_FEAT_ORDERED_HWQ; if (dev->zoned) { rv =3D null_init_zoned_dev(dev, &lim); if (rv) diff --git a/drivers/block/null_blk/null_blk.h b/drivers/block/null_blk/n= ull_blk.h index 7bb6128dbaaf..08b732cf853f 100644 --- a/drivers/block/null_blk/null_blk.h +++ b/drivers/block/null_blk/null_blk.h @@ -110,6 +110,7 @@ struct nullb_device { bool shared_tag_bitmap; /* use hostwide shared tags */ bool fua; /* Support FUA */ bool rotational; /* Fake rotational device */ + bool preserves_write_order; }; =20 struct nullb {