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Commit 8b00c3d5 authored by Finn Thain's avatar Finn Thain Committed by Martin K. Petersen
Browse files

ncr5380: Implement new eh_abort_handler 



Introduce a new eh_abort_handler implementation. This one attempts to
follow all of the rules relating to EH handlers. There is still a known
bug: during selection, a command becomes invisible to the EH handlers
because it only appears in a pointer on the stack of a different thread.
This bug is addressed in a subsequent patch.

Signed-off-by: default avatarFinn Thain <fthain@telegraphics.com.au>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Tested-by: default avatarOndrej Zary <linux@rainbow-software.org>
Tested-by: default avatarMichael Schmitz <schmitzmic@gmail.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent f27db8eb

drivers/scsi/NCR5380.c

+144 −19
Original line number Diff line number Diff line
@@ -2269,23 +2269,65 @@ static void NCR5380_dma_complete(NCR5380_instance * instance) { 
}

#endif				/* def REAL_DMA */



/*

 * Function : int NCR5380_abort (struct scsi_cmnd *cmd)

 *

 * Purpose : abort a command

/**

 * list_find_cmd - test for presence of a command in a linked list

 * @haystack: list of commands

 * @needle: command to search for

 */



static bool list_find_cmd(struct list_head *haystack,

                          struct scsi_cmnd *needle)

{

	struct NCR5380_cmd *ncmd;



	list_for_each_entry(ncmd, haystack, list)

		if (NCR5380_to_scmd(ncmd) == needle)

			return true;

	return false;

}



/**

 * list_remove_cmd - remove a command from linked list

 * @haystack: list of commands

 * @needle: command to remove

 */



static bool list_del_cmd(struct list_head *haystack,

                         struct scsi_cmnd *needle)

{

	if (list_find_cmd(haystack, needle)) {

		struct NCR5380_cmd *ncmd = scsi_cmd_priv(needle);



		list_del(&ncmd->list);

		return true;

	}

	return false;

}



/**

 * NCR5380_abort - scsi host eh_abort_handler() method

 * @cmd: the command to be aborted

 *

 * Inputs : cmd - the scsi_cmnd to abort, code - code to set the

 *      host byte of the result field to, if zero DID_ABORTED is

 *      used.

 * Try to abort a given command by removing it from queues and/or sending

 * the target an abort message. This may not succeed in causing a target

 * to abort the command. Nonetheless, the low-level driver must forget about

 * the command because the mid-layer reclaims it and it may be re-issued.

 *

 * Returns : SUCCESS - success, FAILED on failure.

 * The normal path taken by a command is as follows. For EH we trace this

 * same path to locate and abort the command.

 *

 *	XXX - there is no way to abort the command that is currently

 *	connected, you have to wait for it to complete.  If this is

 *	a problem, we could implement longjmp() / setjmp(), setjmp()

 *	called where the loop started in NCR5380_main().

 * unissued -> selecting -> [unissued -> selecting ->]... connected ->

 * [disconnected -> connected ->]...

 * [autosense -> connected ->] done

 *

 * Locks: host lock taken by caller

 * If cmd is unissued then just remove it.

 * If cmd is disconnected, try to select the target.

 * If cmd is connected, try to send an abort message.

 * If cmd is waiting for autosense, give it a chance to complete but check

 * that it isn't left connected.

 * If cmd was not found at all then presumably it has already been completed,

 * in which case return SUCCESS to try to avoid further EH measures.

 * If the command has not completed yet, we must not fail to find it.

 */



static int NCR5380_abort(struct scsi_cmnd *cmd)
@@ -2293,18 +2335,101 @@ static int NCR5380_abort(struct scsi_cmnd *cmd) 
	struct Scsi_Host *instance = cmd->device->host;

	struct NCR5380_hostdata *hostdata = shost_priv(instance);

	unsigned long flags;

	int result = SUCCESS;



	spin_lock_irqsave(&hostdata->lock, flags);



#if (NDEBUG & NDEBUG_ANY)

	scmd_printk(KERN_INFO, cmd, "aborting command\n");

	scmd_printk(KERN_INFO, cmd, __func__);

#endif

	NCR5380_dprint(NDEBUG_ANY, instance);

	NCR5380_dprint_phase(NDEBUG_ANY, instance);



	if (list_del_cmd(&hostdata->unissued, cmd)) {

		dsprintk(NDEBUG_ABORT, instance,

		         "abort: removed %p from issue queue\n", cmd);

		cmd->result = DID_ABORT << 16;

		cmd->scsi_done(cmd); /* No tag or busy flag to worry about */

	}



	if (list_del_cmd(&hostdata->disconnected, cmd)) {

		dsprintk(NDEBUG_ABORT, instance,

		         "abort: removed %p from disconnected list\n", cmd);

		cmd->result = DID_ERROR << 16;

		if (!hostdata->connected)

			NCR5380_select(instance, cmd);

		if (hostdata->connected != cmd) {

			complete_cmd(instance, cmd);

			result = FAILED;

			goto out;

		}

	}



	if (hostdata->connected == cmd) {

		dsprintk(NDEBUG_ABORT, instance, "abort: cmd %p is connected\n", cmd);

		hostdata->connected = NULL;

		if (do_abort(instance)) {

			set_host_byte(cmd, DID_ERROR);

			complete_cmd(instance, cmd);

			result = FAILED;

			goto out;

		}

		set_host_byte(cmd, DID_ABORT);

#ifdef REAL_DMA

		hostdata->dma_len = 0;

#endif

		if (cmd->cmnd[0] == REQUEST_SENSE)

			complete_cmd(instance, cmd);

		else {

			struct NCR5380_cmd *ncmd = scsi_cmd_priv(cmd);



			/* Perform autosense for this command */

			list_add(&ncmd->list, &hostdata->autosense);

		}

	}



	if (list_find_cmd(&hostdata->autosense, cmd)) {

		dsprintk(NDEBUG_ABORT, instance,

		         "abort: found %p on sense queue\n", cmd);

		spin_unlock_irqrestore(&hostdata->lock, flags);

		queue_work(hostdata->work_q, &hostdata->main_task);

		msleep(1000);

		spin_lock_irqsave(&hostdata->lock, flags);

		if (list_del_cmd(&hostdata->autosense, cmd)) {

			dsprintk(NDEBUG_ABORT, instance,

			         "abort: removed %p from sense queue\n", cmd);

			set_host_byte(cmd, DID_ABORT);

			complete_cmd(instance, cmd);

			goto out;

		}

	}



	if (hostdata->connected == cmd) {

		dsprintk(NDEBUG_ABORT, instance, "abort: cmd %p is connected\n", cmd);

		hostdata->connected = NULL;

		if (do_abort(instance)) {

			set_host_byte(cmd, DID_ERROR);

			complete_cmd(instance, cmd);

			result = FAILED;

			goto out;

		}

		set_host_byte(cmd, DID_ABORT);

#ifdef REAL_DMA

		hostdata->dma_len = 0;

#endif

		complete_cmd(instance, cmd);

	}



out:

	if (result == FAILED)

		dsprintk(NDEBUG_ABORT, instance, "abort: failed to abort %p\n", cmd);

	else

		dsprintk(NDEBUG_ABORT, instance, "abort: successfully aborted %p\n", cmd);



	queue_work(hostdata->work_q, &hostdata->main_task);

	spin_unlock_irqrestore(&hostdata->lock, flags);



	return FAILED;

	return result;

}

drivers/scsi/atari_NCR5380.c

+146 −19
Original line number Diff line number Diff line
@@ -2480,41 +2480,168 @@ static void NCR5380_reselect(struct Scsi_Host *instance) 
}





/*

 * Function : int NCR5380_abort (struct scsi_cmnd *cmd)

/**

 * list_find_cmd - test for presence of a command in a linked list

 * @haystack: list of commands

 * @needle: command to search for

 */



static bool list_find_cmd(struct list_head *haystack,

                          struct scsi_cmnd *needle)

{

	struct NCR5380_cmd *ncmd;



	list_for_each_entry(ncmd, haystack, list)

		if (NCR5380_to_scmd(ncmd) == needle)

			return true;

	return false;

}



/**

 * list_remove_cmd - remove a command from linked list

 * @haystack: list of commands

 * @needle: command to remove

 */



static bool list_del_cmd(struct list_head *haystack,

                         struct scsi_cmnd *needle)

{

	if (list_find_cmd(haystack, needle)) {

		struct NCR5380_cmd *ncmd = scsi_cmd_priv(needle);



		list_del(&ncmd->list);

		return true;

	}

	return false;

}



/**

 * NCR5380_abort - scsi host eh_abort_handler() method

 * @cmd: the command to be aborted

 *

 * Purpose : abort a command

 * Try to abort a given command by removing it from queues and/or sending

 * the target an abort message. This may not succeed in causing a target

 * to abort the command. Nonetheless, the low-level driver must forget about

 * the command because the mid-layer reclaims it and it may be re-issued.

 *

 * Inputs : cmd - the scsi_cmnd to abort, code - code to set the

 *	host byte of the result field to, if zero DID_ABORTED is

 *	used.

 * The normal path taken by a command is as follows. For EH we trace this

 * same path to locate and abort the command.

 *

 * Returns : SUCCESS - success, FAILED on failure.

 * unissued -> selecting -> [unissued -> selecting ->]... connected ->

 * [disconnected -> connected ->]...

 * [autosense -> connected ->] done

 *

 * XXX - there is no way to abort the command that is currently

 *	 connected, you have to wait for it to complete.  If this is

 *	 a problem, we could implement longjmp() / setjmp(), setjmp()

 *	 called where the loop started in NCR5380_main().

 * If cmd is unissued then just remove it.

 * If cmd is disconnected, try to select the target.

 * If cmd is connected, try to send an abort message.

 * If cmd is waiting for autosense, give it a chance to complete but check

 * that it isn't left connected.

 * If cmd was not found at all then presumably it has already been completed,

 * in which case return SUCCESS to try to avoid further EH measures.

 * If the command has not completed yet, we must not fail to find it.

 */



static

int NCR5380_abort(struct scsi_cmnd *cmd)

static int NCR5380_abort(struct scsi_cmnd *cmd)

{

	struct Scsi_Host *instance = cmd->device->host;

	struct NCR5380_hostdata *hostdata = shost_priv(instance);

	unsigned long flags;

	int result = SUCCESS;



	spin_lock_irqsave(&hostdata->lock, flags);



#if (NDEBUG & NDEBUG_ANY)

	scmd_printk(KERN_INFO, cmd, "aborting command\n");

	scmd_printk(KERN_INFO, cmd, __func__);

#endif

	NCR5380_dprint(NDEBUG_ANY, instance);

	NCR5380_dprint_phase(NDEBUG_ANY, instance);



	if (list_del_cmd(&hostdata->unissued, cmd)) {

		dsprintk(NDEBUG_ABORT, instance,

		         "abort: removed %p from issue queue\n", cmd);

		cmd->result = DID_ABORT << 16;

		cmd->scsi_done(cmd); /* No tag or busy flag to worry about */

	}



	if (list_del_cmd(&hostdata->disconnected, cmd)) {

		dsprintk(NDEBUG_ABORT, instance,

		         "abort: removed %p from disconnected list\n", cmd);

		cmd->result = DID_ERROR << 16;

		if (!hostdata->connected)

			NCR5380_select(instance, cmd);

		if (hostdata->connected != cmd) {

			complete_cmd(instance, cmd);

			result = FAILED;

			goto out;

		}

	}



	if (hostdata->connected == cmd) {

		dsprintk(NDEBUG_ABORT, instance, "abort: cmd %p is connected\n", cmd);

		hostdata->connected = NULL;

		if (do_abort(instance)) {

			set_host_byte(cmd, DID_ERROR);

			complete_cmd(instance, cmd);

			result = FAILED;

			goto out;

		}

		set_host_byte(cmd, DID_ABORT);

#ifdef REAL_DMA

		hostdata->dma_len = 0;

#endif

		if (cmd->cmnd[0] == REQUEST_SENSE)

			complete_cmd(instance, cmd);

		else {

			struct NCR5380_cmd *ncmd = scsi_cmd_priv(cmd);



			/* Perform autosense for this command */

			list_add(&ncmd->list, &hostdata->autosense);

		}

	}



	if (list_find_cmd(&hostdata->autosense, cmd)) {

		dsprintk(NDEBUG_ABORT, instance,

		         "abort: found %p on sense queue\n", cmd);

		spin_unlock_irqrestore(&hostdata->lock, flags);

		queue_work(hostdata->work_q, &hostdata->main_task);

		msleep(1000);

		spin_lock_irqsave(&hostdata->lock, flags);

		if (list_del_cmd(&hostdata->autosense, cmd)) {

			dsprintk(NDEBUG_ABORT, instance,

			         "abort: removed %p from sense queue\n", cmd);

			set_host_byte(cmd, DID_ABORT);

			complete_cmd(instance, cmd);

			goto out;

		}

	}



	if (hostdata->connected == cmd) {

		dsprintk(NDEBUG_ABORT, instance, "abort: cmd %p is connected\n", cmd);

		hostdata->connected = NULL;

		if (do_abort(instance)) {

			set_host_byte(cmd, DID_ERROR);

			complete_cmd(instance, cmd);

			result = FAILED;

			goto out;

		}

		set_host_byte(cmd, DID_ABORT);

#ifdef REAL_DMA

		hostdata->dma_len = 0;

#endif

		complete_cmd(instance, cmd);

	}



out:

	if (result == FAILED)

		dsprintk(NDEBUG_ABORT, instance, "abort: failed to abort %p\n", cmd);

	else

		dsprintk(NDEBUG_ABORT, instance, "abort: successfully aborted %p\n", cmd);



	queue_work(hostdata->work_q, &hostdata->main_task);

	maybe_release_dma_irq(instance);

	spin_unlock_irqrestore(&hostdata->lock, flags);



	return FAILED;

	return result;

}