From 4f258a46346c03fa0bbb6199ffaf4e1f9f599660 Mon Sep 17 00:00:00 2001 From: "Martin K. Petersen" Date: Tue, 23 Jun 2015 12:13:59 -0400 Subject: [PATCH] sd: Fix maximum I/O size for BLOCK_PC requests Commit bcdb247c6b6a ("sd: Limit transfer length") clamped the maximum size of an I/O request to the MAXIMUM TRANSFER LENGTH field in the BLOCK LIMITS VPD. This had the unfortunate effect of also limiting the maximum size of non-filesystem requests sent to the device through sg/bsg. Avoid using blk_queue_max_hw_sectors() and set the max_sectors queue limit directly. Also update the comment in blk_limits_max_hw_sectors() to clarify that max_hw_sectors defines the limit for the I/O controller only. Signed-off-by: Martin K. Petersen Reported-by: Brian King Tested-by: Brian King Cc: stable@vger.kernel.org # 3.17+ Signed-off-by: James Bottomley --- block/blk-settings.c | 4 ++-- drivers/scsi/sd.c | 6 +++--- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/block/blk-settings.c b/block/blk-settings.c index 12600bfffca9..e0057d035200 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -241,8 +241,8 @@ EXPORT_SYMBOL(blk_queue_bounce_limit); * Description: * Enables a low level driver to set a hard upper limit, * max_hw_sectors, on the size of requests. max_hw_sectors is set by - * the device driver based upon the combined capabilities of I/O - * controller and storage device. + * the device driver based upon the capabilities of the I/O + * controller. * * max_sectors is a soft limit imposed by the block layer for * filesystem type requests. This value can be overridden on a diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 3b2fcb4fada0..a20da8c25b4f 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -2770,9 +2770,9 @@ static int sd_revalidate_disk(struct gendisk *disk) max_xfer = sdkp->max_xfer_blocks; max_xfer <<= ilog2(sdp->sector_size) - 9; - max_xfer = min_not_zero(queue_max_hw_sectors(sdkp->disk->queue), - max_xfer); - blk_queue_max_hw_sectors(sdkp->disk->queue, max_xfer); + sdkp->disk->queue->limits.max_sectors = + min_not_zero(queue_max_hw_sectors(sdkp->disk->queue), max_xfer); + set_capacity(disk, sdkp->capacity); sd_config_write_same(sdkp); kfree(buffer); -- 2.20.1