From b21a41385118f9a6af3cd96ce71090c5ada52eb5 Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Fri, 5 Aug 2005 21:45:40 -0500 Subject: [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 --- drivers/scsi/scsi.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'drivers/scsi/scsi.c') diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index d1aa95d45a70..4befbc275f94 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: -- cgit v1.2.3