From b21a41385118f9a6af3cd96ce71090c5ada52eb5 Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Fri, 5 Aug 2005 21:45:40 -0500 Subject: [PATCH] [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/advansys.c | 4 ++-- drivers/scsi/scsi.c | 15 +++++++++++++++ include/scsi/scsi_cmnd.h | 8 ++++++-- 3 files changed, 23 insertions(+), 4 deletions(-) diff --git a/drivers/scsi/advansys.c b/drivers/scsi/advansys.c index 0fb9336..37ec541 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 d1aa95d..4befbc2 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 9957f16..bed4b7c 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; -- 2.7.4