From 6780414519f91c2a84da9baa963a940ac916f803 Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Tue, 28 Mar 2017 12:41:26 +0800 Subject: [PATCH] scsi: sd: Consider max_xfer_blocks if opt_xfer_blocks is unusable If device reports a small max_xfer_blocks and a zero opt_xfer_blocks, we end up using BLK_DEF_MAX_SECTORS, which is wrong and r/w of that size may get error. [mkp: tweaked to avoid setting rw_max twice and added typecast] Cc: # v4.4+ Fixes: ca369d51b3e ("block/sd: Fix device-imposed transfer length limits") Signed-off-by: Fam Zheng Signed-off-by: Martin K. Petersen --- drivers/scsi/sd.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index fb9b4d29af0b..906cd6bfa2a9 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -2956,7 +2956,8 @@ static int sd_revalidate_disk(struct gendisk *disk) q->limits.io_opt = logical_to_bytes(sdp, sdkp->opt_xfer_blocks); rw_max = logical_to_sectors(sdp, sdkp->opt_xfer_blocks); } else - rw_max = BLK_DEF_MAX_SECTORS; + 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));