scsi: sd: Check for unaligned partial completion

Commit <f2e767bb5d6e> ("mpt3sas: Force request partial completion
alignment") was not considering the case of commands not operating on
logical block size units (e.g. REQ_OP_ZONE_REPORT and its 64B aligned
partial replies). In this case, forcing alignment of resid to the device
logical block size can break the command result, e.g. in the case of
REQ_OP_ZONE_REPORT, the exact number of zone reported by the device.

Move the partial completion alignement check of mpt3sas to a generic
implementation in sd_done(). The check is added within the default
section of the initial req_op() switch case so that the report and reset
zone commands are ignored. In addition, as sd_done() is not called for
passthrough requests, resid corrections are not done as intended by the
initial mpt3sas patch.

Fixes: f2e767bb5d6e ("mpt3sas: Force request partial completion alignment")
Cc: <stable@vger.kernel.org> # v4.10
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index c7839f6..fb9b4d2 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1783,6 +1783,8 @@ static int sd_done(struct scsi_cmnd *SCpnt)
 {
 	int result = SCpnt->result;
 	unsigned int good_bytes = result ? 0 : scsi_bufflen(SCpnt);
+	unsigned int sector_size = SCpnt->device->sector_size;
+	unsigned int resid;
 	struct scsi_sense_hdr sshdr;
 	struct scsi_disk *sdkp = scsi_disk(SCpnt->request->rq_disk);
 	struct request *req = SCpnt->request;
@@ -1813,6 +1815,21 @@ static int sd_done(struct scsi_cmnd *SCpnt)
 			scsi_set_resid(SCpnt, blk_rq_bytes(req));
 		}
 		break;
+	default:
+		/*
+		 * In case of bogus fw or device, we could end up having
+		 * an unaligned partial completion. Check this here and force
+		 * alignment.
+		 */
+		resid = scsi_get_resid(SCpnt);
+		if (resid & (sector_size - 1)) {
+			sd_printk(KERN_INFO, sdkp,
+				"Unaligned partial completion (resid=%u, sector_sz=%u)\n",
+				resid, sector_size);
+			resid = min(scsi_bufflen(SCpnt),
+				    round_up(resid, sector_size));
+			scsi_set_resid(SCpnt, resid);
+		}
 	}
 
 	if (result) {