prevent systemd-udevd from changing a device's sysfs entry max_sectors_kb back to the default value. - max_sectors_kb can be tweaked for better performance. - udev can be triggered by sg_logs -t or scsi_temperature, ... - sd_revalidate_disk is called from udev by ioctl BLKRRPART Reviewed-by: Scott Teel <scott.teel@xxxxxxxxxxxxx> Signed-off-by: Don Brace <don.brace@xxxxxxxxxxxxx> --- drivers/scsi/sd.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index bea36ad..457dc7c 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -3055,6 +3055,7 @@ static int sd_revalidate_disk(struct gendisk *disk) sector_t old_capacity = sdkp->capacity; unsigned char *buffer; unsigned int dev_max, rw_max; + unsigned int max_sectors; SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_revalidate_disk\n")); @@ -3128,9 +3129,14 @@ 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)); + /* Check for max_sectors_kb update through sysfs */ + if (q->limits.max_sectors < min(rw_max, queue_max_hw_sectors(q))) + max_sectors = q->limits.max_sectors; + else + max_sectors = min(rw_max, queue_max_hw_sectors(q)); + /* Combine with controller limits */ + q->limits.max_sectors = max_sectors; set_capacity(disk, logical_to_sectors(sdp, sdkp->capacity)); sd_config_write_same(sdkp); kfree(buffer);
