ncr5380: Fix autosense bugs
NCR5380_information_transfer() may re-queue a command for autosense,
after calling scsi_eh_prep_cmnd(). This creates several possibilities:
1. Reselection may intervene before the re-queued command gets processed.
If the reconnected command then undergoes autosense, this causes the
scsi_eh_save data from the previous command to be overwritten.
2. After NCR5380_information_transfer() calls scsi_eh_prep_cmnd(),
a new REQUEST SENSE command may arrive. This would be queued ahead
of any command already undergoing autosense, which means the
scsi_eh_save data might be restored to the wrong command.
3. After NCR5380_information_transfer() calls scsi_eh_prep_cmnd(),
eh_abort_handler() may abort the command. But the scsi_eh_save data is
not discarded, which means the scsi_eh_save data might be incorrectly
restored to the next REQUEST SENSE command issued.
This patch adds a new autosense list so that commands that are re-queued
because of a CHECK CONDITION result can be kept apart from the REQUEST
SENSE commands that arrive via queuecommand.
This patch also adds a function dedicated to dequeueing and preparing the
next command for processing. By refactoring the main loop in this way,
scsi_eh_save takes place when an autosense command is dequeued rather
than when re-queued.
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Ondrej Zary <linux@rainbow-software.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c
index 0831916..2c9133f 100644
--- a/drivers/scsi/NCR5380.c
+++ b/drivers/scsi/NCR5380.c
@@ -244,6 +244,9 @@
cmd->SCp.ptr = NULL;
cmd->SCp.this_residual = 0;
}
+
+ cmd->SCp.Status = 0;
+ cmd->SCp.Message = 0;
}
/**
@@ -622,6 +625,8 @@
#endif
spin_lock_init(&hostdata->lock);
hostdata->connected = NULL;
+ hostdata->sensing = NULL;
+ INIT_LIST_HEAD(&hostdata->autosense);
INIT_LIST_HEAD(&hostdata->unissued);
INIT_LIST_HEAD(&hostdata->disconnected);
@@ -738,6 +743,16 @@
dsprintk(NDEBUG_QUEUES, instance, "complete_cmd: cmd %p\n", cmd);
+ if (hostdata->sensing == cmd) {
+ /* Autosense processing ends here */
+ if ((cmd->result & 0xff) != SAM_STAT_GOOD) {
+ scsi_eh_restore_cmnd(cmd, &hostdata->ses);
+ set_host_byte(cmd, DID_ERROR);
+ } else
+ scsi_eh_restore_cmnd(cmd, &hostdata->ses);
+ hostdata->sensing = NULL;
+ }
+
hostdata->busy[scmd_id(cmd)] &= ~(1 << cmd->device->lun);
cmd->scsi_done(cmd);
@@ -798,6 +813,64 @@
}
/**
+ * dequeue_next_cmd - dequeue a command for processing
+ * @instance: the scsi host instance
+ *
+ * Priority is given to commands on the autosense queue. These commands
+ * need autosense because of a CHECK CONDITION result.
+ *
+ * Returns a command pointer if a command is found for a target that is
+ * not already busy. Otherwise returns NULL.
+ */
+
+static struct scsi_cmnd *dequeue_next_cmd(struct Scsi_Host *instance)
+{
+ struct NCR5380_hostdata *hostdata = shost_priv(instance);
+ struct NCR5380_cmd *ncmd;
+ struct scsi_cmnd *cmd;
+
+ if (list_empty(&hostdata->autosense)) {
+ list_for_each_entry(ncmd, &hostdata->unissued, list) {
+ cmd = NCR5380_to_scmd(ncmd);
+ dsprintk(NDEBUG_QUEUES, instance, "dequeue: cmd=%p target=%d busy=0x%02x lun=%llu\n",
+ cmd, scmd_id(cmd), hostdata->busy[scmd_id(cmd)], cmd->device->lun);
+
+ if (!(hostdata->busy[scmd_id(cmd)] & (1 << cmd->device->lun))) {
+ list_del(&ncmd->list);
+ dsprintk(NDEBUG_QUEUES, instance,
+ "dequeue: removed %p from issue queue\n", cmd);
+ return cmd;
+ }
+ }
+ } else {
+ /* Autosense processing begins here */
+ ncmd = list_first_entry(&hostdata->autosense,
+ struct NCR5380_cmd, list);
+ list_del(&ncmd->list);
+ cmd = NCR5380_to_scmd(ncmd);
+ dsprintk(NDEBUG_QUEUES, instance,
+ "dequeue: removed %p from autosense queue\n", cmd);
+ scsi_eh_prep_cmnd(cmd, &hostdata->ses, NULL, 0, ~0);
+ hostdata->sensing = cmd;
+ return cmd;
+ }
+ return NULL;
+}
+
+static void requeue_cmd(struct Scsi_Host *instance, struct scsi_cmnd *cmd)
+{
+ struct NCR5380_hostdata *hostdata = shost_priv(instance);
+ struct NCR5380_cmd *ncmd = scsi_cmd_priv(cmd);
+
+ if (hostdata->sensing) {
+ scsi_eh_restore_cmnd(cmd, &hostdata->ses);
+ list_add(&ncmd->list, &hostdata->autosense);
+ hostdata->sensing = NULL;
+ } else
+ list_add(&ncmd->list, &hostdata->unissued);
+}
+
+/**
* NCR5380_main - NCR state machines
*
* NCR5380_main is a coroutine that runs as long as more work can
@@ -814,63 +887,40 @@
struct NCR5380_hostdata *hostdata =
container_of(work, struct NCR5380_hostdata, main_task);
struct Scsi_Host *instance = hostdata->host;
- struct NCR5380_cmd *ncmd, *n;
+ struct scsi_cmnd *cmd;
int done;
spin_lock_irq(&hostdata->lock);
do {
done = 1;
- if (!hostdata->connected) {
- dprintk(NDEBUG_MAIN, "scsi%d : not connected\n", instance->host_no);
+ while (!hostdata->connected &&
+ (cmd = dequeue_next_cmd(instance))) {
+
+ dsprintk(NDEBUG_MAIN, instance, "main: dequeued %p\n", cmd);
+
/*
- * Search through the issue_queue for a command destined
- * for a target that's not busy.
+ * Attempt to establish an I_T_L nexus here.
+ * On success, instance->hostdata->connected is set.
+ * On failure, we must add the command back to the
+ * issue queue so we can keep trying.
*/
- list_for_each_entry_safe(ncmd, n, &hostdata->unissued,
- list) {
- struct scsi_cmnd *tmp = NCR5380_to_scmd(ncmd);
+ /*
+ * REQUEST SENSE commands are issued without tagged
+ * queueing, even on SCSI-II devices because the
+ * contingent allegiance condition exists for the
+ * entire unit.
+ */
- dsprintk(NDEBUG_QUEUES, instance, "main: tmp=%p target=%d busy=%d lun=%llu\n",
- tmp, scmd_id(tmp), hostdata->busy[scmd_id(tmp)],
- tmp->device->lun);
- /* When we find one, remove it from the issue queue. */
- if (!(hostdata->busy[tmp->device->id] &
- (1 << (u8)(tmp->device->lun & 0xff)))) {
- list_del(&ncmd->list);
- dsprintk(NDEBUG_MAIN | NDEBUG_QUEUES,
- instance, "main: removed %p from issue queue\n",
- tmp);
-
- /*
- * Attempt to establish an I_T_L nexus here.
- * On success, instance->hostdata->connected is set.
- * On failure, we must add the command back to the
- * issue queue so we can keep trying.
- */
- /*
- * REQUEST SENSE commands are issued without tagged
- * queueing, even on SCSI-II devices because the
- * contingent allegiance condition exists for the
- * entire unit.
- */
-
- if (!NCR5380_select(instance, tmp)) {
- /* OK or bad target */
- } else {
- /* Need to retry */
- list_add(&ncmd->list, &hostdata->unissued);
- dsprintk(NDEBUG_MAIN | NDEBUG_QUEUES,
- instance, "main: select() failed, %p returned to issue queue\n",
- tmp);
- done = 0;
- }
- if (hostdata->connected)
- break;
- } /* if target/lun is not busy */
- } /* for */
- } /* if (!hostdata->connected) */
-
+ if (!NCR5380_select(instance, cmd)) {
+ dsprintk(NDEBUG_MAIN, instance, "main: selected target %d for command %p\n",
+ scmd_id(cmd), cmd);
+ } else {
+ dsprintk(NDEBUG_MAIN | NDEBUG_QUEUES, instance,
+ "main: select failed, returning %p to queue\n", cmd);
+ requeue_cmd(instance, cmd);
+ }
+ }
if (hostdata->connected
#ifdef REAL_DMA
&& !hostdata->dmalen
@@ -1853,43 +1903,21 @@
hostdata->connected = NULL;
- /*
- * I'm not sure what the correct thing to do here is :
- *
- * If the command that just executed is NOT a request
- * sense, the obvious thing to do is to set the result
- * code to the values of the stored parameters.
- *
- * If it was a REQUEST SENSE command, we need some way
- * to differentiate between the failure code of the original
- * and the failure code of the REQUEST sense - the obvious
- * case is success, where we fall through and leave the result
- * code unchanged.
- *
- * The non-obvious place is where the REQUEST SENSE failed
- */
+ cmd->result &= ~0xffff;
+ cmd->result |= cmd->SCp.Status;
+ cmd->result |= cmd->SCp.Message << 8;
- if (cmd->cmnd[0] != REQUEST_SENSE)
- cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8);
- else if (status_byte(cmd->SCp.Status) != GOOD)
- cmd->result = (cmd->result & 0x00ffff) | (DID_ERROR << 16);
-
- if ((cmd->cmnd[0] == REQUEST_SENSE) &&
- hostdata->ses.cmd_len) {
- scsi_eh_restore_cmnd(cmd, &hostdata->ses);
- hostdata->ses.cmd_len = 0 ;
- }
-
- if ((cmd->cmnd[0] != REQUEST_SENSE) && (status_byte(cmd->SCp.Status) == CHECK_CONDITION)) {
- scsi_eh_prep_cmnd(cmd, &hostdata->ses, NULL, 0, ~0);
-
- list_add(&ncmd->list, &hostdata->unissued);
- dsprintk(NDEBUG_AUTOSENSE | NDEBUG_QUEUES,
- instance, "REQUEST SENSE cmd %p added to head of issue queue\n",
- cmd);
- hostdata->busy[cmd->device->id] &= ~(1 << (cmd->device->lun & 0xFF));
- } else {
+ if (cmd->cmnd[0] == REQUEST_SENSE)
complete_cmd(instance, cmd);
+ else {
+ if (cmd->SCp.Status == SAM_STAT_CHECK_CONDITION ||
+ cmd->SCp.Status == SAM_STAT_COMMAND_TERMINATED) {
+ dsprintk(NDEBUG_QUEUES, instance, "autosense: adding cmd %p to tail of autosense queue\n",
+ cmd);
+ list_add_tail(&ncmd->list,
+ &hostdata->autosense);
+ } else
+ complete_cmd(instance, cmd);
}
/*