From 3a9794d32984b67a6d8992226918618f0e51e5d5 Mon Sep 17 00:00:00 2001 From: Brian King Date: Thu, 29 Jan 2015 15:54:40 -0600 Subject: [PATCH] sd: Fix max transfer length for 4k disks The following patch fixes an issue observed with 4k sector disks where the max_hw_sectors attribute was getting set too large in sd_revalidate_disk. Since sdkp->max_xfer_blocks is in units of SCSI logical blocks and queue_max_hw_sectors is in units of 512 byte blocks, on a 4k sector disk, every time we went through sd_revalidate_disk, we were taking the current value of queue_max_hw_sectors and increasing it by a factor of 8. Fix this by only shifting sdkp->max_xfer_blocks. Cc: stable@vger.kernel.org Signed-off-by: Brian King Reviewed-by: Paolo Bonzini Reviewed-by: Martin K. Petersen Signed-off-by: Christoph Hellwig --- drivers/scsi/sd.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 399516925d80..05ea0d49a3a3 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -2800,9 +2800,11 @@ static int sd_revalidate_disk(struct gendisk *disk) */ sd_set_flush_flag(sdkp); - max_xfer = min_not_zero(queue_max_hw_sectors(sdkp->disk->queue), - sdkp->max_xfer_blocks); + 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); set_capacity(disk, sdkp->capacity); sd_config_write_same(sdkp); -- 2.20.1