Commit b21a4138 authored by James Bottomley's avatar James Bottomley Committed by James Bottomley
Browse files

[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: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
parent f03a5670

drivers/scsi/advansys.c

+2 −2
Original line number Diff line number Diff line
@@ -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",

































drivers/scsi/scsi.c



+15
−0






























Original line number
Diff line number
Diff line








@@ -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:

































include/scsi/scsi_cmnd.h



+6
−2






























Original line number
Diff line number
Diff line








@@ -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;



































































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