Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit b21a4138 authored Aug 05, 2005 by James Bottomley Committed by James Bottomley Aug 08, 2005

[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>

parent f03a5670

drivers/scsi/advansys.c

+2 −2

Original line number	Original line	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);		(unsigned) s->serial_number, s->retries, s->allowed);

	printk(		printk(
	" timeout_per_command %d, timeout_total %d, timeout %d\n",		" timeout_per_command %d\n",
	s->timeout_per_command, s->timeout_total, s->timeout);		s->timeout_per_command);

	printk(		printk(
	" scsi_done 0x%lx, done 0x%lx, host_scribble 0x%lx, result 0x%x\n",		" scsi_done 0x%lx, done 0x%lx, host_scribble 0x%lx, result 0x%x\n",

drivers/scsi/scsi.c

+15 −0

Original line number	Original line	Diff line number	Diff line
	@@ -268,6 +268,7 @@ struct scsi_cmnd scsi_get_command(struct scsi_device dev, int gfp_mask)
	} else		} else
	put_device(&dev->sdev_gendev);		put_device(&dev->sdev_gendev);

			cmd->jiffies_at_alloc = jiffies;
	return cmd;		return cmd;
	}		}
	EXPORT_SYMBOL(scsi_get_command);		EXPORT_SYMBOL(scsi_get_command);
	@@ -798,9 +799,23 @@ static void scsi_softirq(struct softirq_action *h)
	while (!list_empty(&local_q)) {		while (!list_empty(&local_q)) {
	struct scsi_cmnd *cmd = list_entry(local_q.next,		struct scsi_cmnd *cmd = list_entry(local_q.next,
	struct scsi_cmnd, eh_entry);		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);		list_del_init(&cmd->eh_entry);

	disposition = scsi_decide_disposition(cmd);		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);		scsi_log_completion(cmd, disposition);
	switch (disposition) {		switch (disposition) {
	case SUCCESS:		case SUCCESS:

include/scsi/scsi_cmnd.h

+6 −2

Original line number	Original line	Diff line number	Diff line
	@@ -51,12 +51,16 @@ struct scsi_cmnd {
	* printk's to use ->pid, so that we can kill this field.		* printk's to use ->pid, so that we can kill this field.
	*/		*/
	unsigned long serial_number;		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 retries;
	int allowed;		int allowed;
	int timeout_per_command;		int timeout_per_command;
	int timeout_total;
	int timeout;

	unsigned char cmd_len;		unsigned char cmd_len;
	unsigned char old_cmd_len;		unsigned char old_cmd_len;