diff options
| author | Martin K. Petersen <martin.petersen@oracle.com> | 2017-09-27 21:38:59 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-10-12 11:27:33 +0200 |
| commit | 9e78ac87626a92fdf71e519f71a76c6f6d4dfea3 (patch) | |
| tree | d274f7a8773e97fea9ea4e221dbe74ec953bb142 | |
| parent | fc29713fa7c78fda30855444eeab2d5ea8088762 (diff) | |
scsi: sd: Do not override max_sectors_kb sysfs setting
commit 77082ca503bed061f7fbda7cfd7c93beda967a41 upstream.
A user may lower the max_sectors_kb setting in sysfs to accommodate
certain workloads. Previously we would always set the max I/O size to
either the block layer default or the optional preferred I/O size
reported by the device.
Keep the current heuristics for the initial setting of max_sectors_kb.
For subsequent invocations, only update the current queue limit if it
exceeds the capabilities of the hardware.
Reported-by: Don Brace <don.brace@microsemi.com>
Reviewed-by: Martin Wilck <mwilck@suse.com>
Tested-by: Don Brace <don.brace@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/scsi/sd.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 8750c86f95f9..7e1681cf287c 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -2878,8 +2878,6 @@ static int sd_revalidate_disk(struct gendisk *disk) sd_read_write_same(sdkp, buffer); } - sdkp->first_scan = 0; - /* * We now have all cache related info, determine how we deal * with flush requests. @@ -2894,7 +2892,7 @@ static int sd_revalidate_disk(struct gendisk *disk) q->limits.max_dev_sectors = logical_to_sectors(sdp, dev_max); /* - * Use the device's preferred I/O size for reads and writes + * Determine the device's preferred I/O size for reads and writes * unless the reported value is unreasonably small, large, or * garbage. */ @@ -2908,8 +2906,19 @@ static int sd_revalidate_disk(struct gendisk *disk) rw_max = min_not_zero(logical_to_sectors(sdp, dev_max), (sector_t)BLK_DEF_MAX_SECTORS); - /* Combine with controller limits */ - q->limits.max_sectors = min(rw_max, queue_max_hw_sectors(q)); + /* Do not exceed controller limit */ + rw_max = min(rw_max, queue_max_hw_sectors(q)); + + /* + * Only update max_sectors if previously unset or if the current value + * exceeds the capabilities of the hardware. + */ + if (sdkp->first_scan || + q->limits.max_sectors > q->limits.max_dev_sectors || + q->limits.max_sectors > q->limits.max_hw_sectors) + q->limits.max_sectors = rw_max; + + sdkp->first_scan = 0; set_capacity(disk, logical_to_sectors(sdp, sdkp->capacity)); sd_config_write_same(sdkp); |