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authorJames Bottomley <James.Bottomley@steeleye.com>2005-08-05 21:45:40 -0500
committerJames Bottomley <jejb@mulgrave.(none)>2005-08-08 09:55:39 -0500
commitb21a41385118f9a6af3cd96ce71090c5ada52eb5 (patch)
tree4eb9124ae72e1a905094c259465718793698e603
parentf03a567054fea4f9d43c50ec91338266c0bd588d (diff)
[SCSI] add global timeout to the scsi mid-layer
There are certain rogue devices (and the aic7xxx driver) that return BUSY or QUEUE_FULL forever. This code will apply a global timeout (of the total number of retries times the per command timer) to a given command. If it is exceeded, the command is completed regardless of its state. The patch also removes the unused field in the command: timeout and timeout_total. This solves the problem of detecting an endless loop in the mid-layer because of BUSY/QUEUE_FULL bouncing, but will not recover the device. In the aic7xxx case, the driver can be recovered by sending a bus reset, so possibly this should be tied into the error handler? Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
-rw-r--r--drivers/scsi/advansys.c4
-rw-r--r--drivers/scsi/scsi.c15
-rw-r--r--include/scsi/scsi_cmnd.h8
3 files changed, 23 insertions, 4 deletions
diff --git a/drivers/scsi/advansys.c b/drivers/scsi/advansys.c
index 0fb93363eb2..37ec5411e32 100644
--- a/drivers/scsi/advansys.c
+++ b/drivers/scsi/advansys.c
@@ -9200,8 +9200,8 @@ asc_prt_scsi_cmnd(struct scsi_cmnd *s)
(unsigned) s->serial_number, s->retries, s->allowed);
printk(
-" timeout_per_command %d, timeout_total %d, timeout %d\n",
- s->timeout_per_command, s->timeout_total, s->timeout);
+" timeout_per_command %d\n",
+ s->timeout_per_command);
printk(
" scsi_done 0x%lx, done 0x%lx, host_scribble 0x%lx, result 0x%x\n",
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index d1aa95d45a7..4befbc275f9 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -268,6 +268,7 @@ struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, int gfp_mask)
} else
put_device(&dev->sdev_gendev);
+ cmd->jiffies_at_alloc = jiffies;
return cmd;
}
EXPORT_SYMBOL(scsi_get_command);
@@ -798,9 +799,23 @@ static void scsi_softirq(struct softirq_action *h)
while (!list_empty(&local_q)) {
struct scsi_cmnd *cmd = list_entry(local_q.next,
struct scsi_cmnd, eh_entry);
+ /* The longest time any command should be outstanding is the
+ * per command timeout multiplied by the number of retries.
+ *
+ * For a typical command, this is 2.5 minutes */
+ unsigned long wait_for
+ = cmd->allowed * cmd->timeout_per_command;
list_del_init(&cmd->eh_entry);
disposition = scsi_decide_disposition(cmd);
+ if (disposition != SUCCESS &&
+ time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
+ dev_printk(KERN_ERR, &cmd->device->sdev_gendev,
+ "timing out command, waited %ds\n",
+ wait_for/HZ);
+ disposition = SUCCESS;
+ }
+
scsi_log_completion(cmd, disposition);
switch (disposition) {
case SUCCESS:
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 9957f16dcc5..bed4b7c9be9 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -51,12 +51,16 @@ struct scsi_cmnd {
* printk's to use ->pid, so that we can kill this field.
*/
unsigned long serial_number;
+ /*
+ * This is set to jiffies as it was when the command was first
+ * allocated. It is used to time how long the command has
+ * been outstanding
+ */
+ unsigned long jiffies_at_alloc;
int retries;
int allowed;
int timeout_per_command;
- int timeout_total;
- int timeout;
unsigned char cmd_len;
unsigned char old_cmd_len;