Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull SCSI fixes from James Bottomley:
"Two straightforward fixes.
One is a concurrency issue only affecting SAS connected SATA drives,
but which could hang the storage subsystem if it triggers (because the
outstanding command count on error never goes back to zero) and the
other is a NO_TAG fallout from the switch to hostwide tags which
causes the system to crash on module insertion (we've checked
carefully and only the 53c700 family of drivers is vulnerable to this
issue)"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
53c700: fix BUG on untagged commands
scsi: fix race between simultaneous decrements of ->host_failed
diff --git a/Documentation/scsi/scsi_eh.txt b/Documentation/scsi/scsi_eh.txt
index 8638f61..37eca00 100644
--- a/Documentation/scsi/scsi_eh.txt
+++ b/Documentation/scsi/scsi_eh.txt
@@ -263,19 +263,23 @@
3. scmd recovered
ACTION: scsi_eh_finish_cmd() is invoked to EH-finish scmd
- - shost->host_failed--
- clear scmd->eh_eflags
- scsi_setup_cmd_retry()
- move from local eh_work_q to local eh_done_q
LOCKING: none
+ CONCURRENCY: at most one thread per separate eh_work_q to
+ keep queue manipulation lockless
4. EH completes
ACTION: scsi_eh_flush_done_q() retries scmds or notifies upper
- layer of failure.
+ layer of failure. May be called concurrently but must have
+ a no more than one thread per separate eh_work_q to
+ manipulate the queue locklessly
- scmd is removed from eh_done_q and scmd->eh_entry is cleared
- if retry is necessary, scmd is requeued using
scsi_queue_insert()
- otherwise, scsi_finish_command() is invoked for scmd
+ - zero shost->host_failed
LOCKING: queue or finish function performs appropriate locking
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 61dc7a9..c6f0174 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -606,7 +606,7 @@
ata_scsi_port_error_handler(host, ap);
/* finish or retry handled scmd's and clean up */
- WARN_ON(host->host_failed || !list_empty(&eh_work_q));
+ WARN_ON(!list_empty(&eh_work_q));
DPRINTK("EXIT\n");
}
diff --git a/drivers/scsi/53c700.c b/drivers/scsi/53c700.c
index d4c2856..3ddc85e 100644
--- a/drivers/scsi/53c700.c
+++ b/drivers/scsi/53c700.c
@@ -1122,7 +1122,7 @@
} else {
struct scsi_cmnd *SCp;
- SCp = scsi_host_find_tag(SDp->host, SCSI_NO_TAG);
+ SCp = SDp->current_cmnd;
if(unlikely(SCp == NULL)) {
sdev_printk(KERN_ERR, SDp,
"no saved request for untagged cmd\n");
@@ -1826,7 +1826,7 @@
slot->tag, slot);
} else {
slot->tag = SCSI_NO_TAG;
- /* must populate current_cmnd for scsi_host_find_tag to work */
+ /* save current command for reselection */
SCp->device->current_cmnd = SCp;
}
/* sanity check: some of the commands generated by the mid-layer
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index a8b610e..106a6ad 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1128,7 +1128,6 @@
*/
void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
{
- scmd->device->host->host_failed--;
scmd->eh_eflags = 0;
list_move_tail(&scmd->eh_entry, done_q);
}
@@ -2227,6 +2226,9 @@
else
scsi_unjam_host(shost);
+ /* All scmds have been handled */
+ shost->host_failed = 0;
+
/*
* Note - if the above fails completely, the action is to take
* individual devices offline and flush the queue of any
