From: John Garry <john.garry@huawei.com>
To: <jejb@linux.ibm.com>, <martin.petersen@oracle.com>, <hch@lst.de>,
<damien.lemoal@opensource.wdc.com>
Cc: <linux-scsi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<iommu@lists.linux.dev>, John Garry <john.garry@huawei.com>
Subject: [PATCH] scsi: sd: Add a comment about limiting max_sectors to shost optimal limit
Date: Tue, 19 Jul 2022 17:51:04 +0800 [thread overview]
Message-ID: <1658224264-49972-1-git-send-email-john.garry@huawei.com> (raw)
Add a comment about limiting the default the SCSI disk request_queue
max_sectors initial value to that of the SCSI host optimal sectors limit.
Suggested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: John Garry <john.garry@huawei.com>
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 3eaee1f7aaca..ed9f43f9512e 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3296,6 +3296,11 @@ static int sd_revalidate_disk(struct gendisk *disk)
(sector_t)BLK_DEF_MAX_SECTORS);
}
+ /*
+ * Limit default to SCSI host optimal sector limit if set. There may be
+ * an impact on performance for when the size of a request exceeds this
+ * host limit.
+ */
rw_max = min_not_zero(rw_max, sdp->host->opt_sectors);
/* Do not exceed controller limit */
--
2.35.3
next reply other threads:[~2022-07-19 9:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-19 9:51 John Garry [this message]
2022-07-19 10:06 ` [PATCH] scsi: sd: Add a comment about limiting max_sectors to shost optimal limit Damien Le Moal
2022-07-20 1:21 ` Martin K. Petersen
2022-07-22 15:15 ` Christoph Hellwig
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