From 9b91fd34b46ded81232de3ce41b9b662ec74b07f Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Mon, 12 Feb 2018 10:57:52 -0800 Subject: scsi: core: Reduce number of scsi_test_unit_ready() retries Make scsi_test_unit_ready() send at most as many TURs as specified in the 'retries' argument instead of retries * (retries + 1) / 2. Signed-off-by: Bart Van Assche Reviewed-by: Hannes Reinecke Signed-off-by: Martin K. Petersen --- drivers/scsi/scsi_lib.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/scsi/scsi_lib.c') diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index a86df9ca7d1c..aea5a1ae318b 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2607,7 +2607,7 @@ scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries, /* try to eat the UNIT_ATTENTION if there are enough retries */ do { result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr, - timeout, retries, NULL); + timeout, 1, NULL); if (sdev->removable && scsi_sense_valid(sshdr) && sshdr->sense_key == UNIT_ATTENTION) sdev->changed = 1; -- cgit v1.2.3 From 2f793a27d58f0fb302f8e162b46fe4b366bbdedd Mon Sep 17 00:00:00 2001 From: Jianchao Wang Date: Sat, 3 Mar 2018 09:54:09 +0800 Subject: scsi: core: use blk_mq_requeue_request in __scsi_queue_insert In scsi core, __scsi_queue_insert should just put request back on the queue and retry using the same command as before. However, for blk-mq, scsi_mq_requeue_cmd is employed here which will unprepare the request. To align with the semantics of __scsi_queue_insert, use blk_mq_requeue_request with kick_requeue_list == true and put the reference of scsi_device. Cc: Christoph Hellwig Signed-off-by: Jianchao Wang Reviewed-by: Bart Van Assche Signed-off-by: Martin K. Petersen --- drivers/scsi/scsi_lib.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) (limited to 'drivers/scsi/scsi_lib.c') diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index aea5a1ae318b..10430d500792 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -191,7 +191,19 @@ static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy) */ cmd->result = 0; if (q->mq_ops) { - scsi_mq_requeue_cmd(cmd); + /* + * Before a SCSI command is dispatched, + * get_device(&sdev->sdev_gendev) is called and the host, + * target and device busy counters are increased. Since + * requeuing a request causes these actions to be repeated and + * since scsi_device_unbusy() has already been called, + * put_device(&device->sdev_gendev) must still be called. Call + * put_device() after blk_mq_requeue_request() to avoid that + * removal of the SCSI device can start before requeueing has + * happened. + */ + blk_mq_requeue_request(cmd->request, true); + put_device(&device->sdev_gendev); return; } spin_lock_irqsave(q->queue_lock, flags); -- cgit v1.2.3 From 1875ede02ed5e176a18dccbca84abc28d5b3e141 Mon Sep 17 00:00:00 2001 From: Douglas Gilbert Date: Tue, 6 Mar 2018 22:19:49 -0500 Subject: scsi: core: Make SCSI Status CONDITION MET equivalent to GOOD The SCSI PRE-FETCH (10 or 16) command is present both on hard disks and some SSDs. It is useful when the address of the next block(s) to be read is known but it is not following the LBA of the current READ (so read-ahead won't help). It returns two "good" SCSI Status values. If the requested blocks have fitted (or will most likely fit (when the IMMED bit is set)) into the disk's cache, it returns CONDITION MET. If it didn't (or will not) fit then it returns GOOD status. The goal of this patch is to stop the SCSI subsystem treating the CONDITION MET SCSI status as an error. The current state makes the PRE-FETCH command effectively unusable via pass-throughs. Signed-off-by: Douglas Gilbert Reviewed-by: Bart Van Assche Signed-off-by: Martin K. Petersen --- drivers/scsi/scsi_lib.c | 11 +++++++++++ include/scsi/scsi.h | 2 ++ 2 files changed, 13 insertions(+) (limited to 'drivers/scsi/scsi_lib.c') diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 10430d500792..393f9db8f41b 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -867,6 +867,17 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) /* for passthrough error may be set */ error = BLK_STS_OK; } + /* + * Another corner case: the SCSI status byte is non-zero but 'good'. + * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when + * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD + * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related + * intermediate statuses (both obsolete in SAM-4) as good. + */ + if (status_byte(result) && scsi_status_is_good(result)) { + result = 0; + error = BLK_STS_OK; + } /* * special case: failed zero length commands always need to diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h index cb85eddb47ea..eb7853c1a23b 100644 --- a/include/scsi/scsi.h +++ b/include/scsi/scsi.h @@ -47,6 +47,8 @@ static inline int scsi_status_is_good(int status) */ status &= 0xfe; return ((status == SAM_STAT_GOOD) || + (status == SAM_STAT_CONDITION_MET) || + /* Next two "intermediate" statuses are obsolete in SAM-4 */ (status == SAM_STAT_INTERMEDIATE) || (status == SAM_STAT_INTERMEDIATE_CONDITION_MET) || /* FIXME: this is obsolete in SAM-3 */ -- cgit v1.2.3