From: Stefan Haberland sth@linux.ibm.com
[ Upstream commit 590ce6d96d6a224b470a3862c33a483d5022bfdb ]
For DASD devices in raw_track_access mode only full track images are read and written. For this purpose it is not necessary to do search operation in the locate record extended function. The documentation even states that this might fail if the searched record is not found on a track.
Currently the driver sets a value of 1 in the search field for the first record after record zero. This is the default for disks not in raw_track_access mode but record 1 might be missing on a completely empty track.
There has not been any problem with this on IBM storage servers but it might lead to errors with DASD devices on other vendors storage servers.
Fix this by setting the search field to 0. Record zero is always available even on a completely empty track.
Fixes: e4dbb0f2b5dd ("[S390] dasd: Add support for raw ECKD access.") Signed-off-by: Stefan Haberland sth@linux.ibm.com Reviewed-by: Jan Hoeppner hoeppner@linux.ibm.com Link: https://lore.kernel.org/r/20221123160719.3002694-4-sth@linux.ibm.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/s390/block/dasd_eckd.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c index aa651403546f..ab20730865e8 100644 --- a/drivers/s390/block/dasd_eckd.c +++ b/drivers/s390/block/dasd_eckd.c @@ -3783,7 +3783,6 @@ static struct dasd_ccw_req *dasd_eckd_build_cp_raw(struct dasd_device *startdev, struct dasd_device *basedev; struct req_iterator iter; struct dasd_ccw_req *cqr; - unsigned int first_offs; unsigned int trkcount; unsigned long *idaws; unsigned int size; @@ -3817,7 +3816,6 @@ static struct dasd_ccw_req *dasd_eckd_build_cp_raw(struct dasd_device *startdev, last_trk = (blk_rq_pos(req) + blk_rq_sectors(req) - 1) / DASD_RAW_SECTORS_PER_TRACK; trkcount = last_trk - first_trk + 1; - first_offs = 0;
if (rq_data_dir(req) == READ) cmd = DASD_ECKD_CCW_READ_TRACK; @@ -3861,13 +3859,13 @@ static struct dasd_ccw_req *dasd_eckd_build_cp_raw(struct dasd_device *startdev,
if (use_prefix) { prefix_LRE(ccw++, data, first_trk, last_trk, cmd, basedev, - startdev, 1, first_offs + 1, trkcount, 0, 0); + startdev, 1, 0, trkcount, 0, 0); } else { define_extent(ccw++, data, first_trk, last_trk, cmd, basedev, 0); ccw[-1].flags |= CCW_FLAG_CC;
data += sizeof(struct DE_eckd_data); - locate_record_ext(ccw++, data, first_trk, first_offs + 1, + locate_record_ext(ccw++, data, first_trk, 0, trkcount, cmd, basedev, 0, 0); }