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Commit 6f4267e3 authored by James Bottomley's avatar James Bottomley
Browse files

[SCSI] Update the SCSI state model to allow blocking in the created state 



Brian King <brking@linux.vnet.ibm.com> reported that fibre channel
devices can oops during scanning if their ports block (because the
device goes from CREATED -> BLOCK -> RUNNING rather than CREATED ->
BLOCK -> CREATED).

Fix this by adding a new state: CREATED_BLOCK which can only transition
back to CREATED and disallow the CREATED -> BLOCK transition.  Now both
the created and blocked states that the mid-layer recognises can include
CREATED_BLOCK.

Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
parent 0f1d87a2

drivers/scsi/scsi_lib.c

+30 −9
Original line number Diff line number Diff line
@@ -1251,6 +1251,7 @@ int scsi_prep_state_check(struct scsi_device *sdev, struct request *req) 
			break;

		case SDEV_QUIESCE:

		case SDEV_BLOCK:

		case SDEV_CREATED_BLOCK:

			/*

			 * If the devices is blocked we defer normal commands.

			 */
@@ -2064,10 +2065,13 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) 


	switch (state) {

	case SDEV_CREATED:

		/* There are no legal states that come back to

		 * created.  This is the manually initialised start

		 * state */

		switch (oldstate) {

		case SDEV_CREATED_BLOCK:

			break;

		default:

			goto illegal;

		}

		break;

			

	case SDEV_RUNNING:

		switch (oldstate) {
@@ -2105,8 +2109,17 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) 


	case SDEV_BLOCK:

		switch (oldstate) {

		case SDEV_CREATED:

		case SDEV_RUNNING:

		case SDEV_CREATED_BLOCK:

			break;

		default:

			goto illegal;

		}

		break;



	case SDEV_CREATED_BLOCK:

		switch (oldstate) {

		case SDEV_CREATED:

			break;

		default:

			goto illegal;
@@ -2394,8 +2407,12 @@ scsi_internal_device_block(struct scsi_device *sdev) 
	int err = 0;



	err = scsi_device_set_state(sdev, SDEV_BLOCK);

	if (err) {

		err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);



		if (err)

			return err;

	}



	/* 

	 * The device has transitioned to SDEV_BLOCK.  Stop the
@@ -2438,8 +2455,12 @@ scsi_internal_device_unblock(struct scsi_device *sdev) 
	 * and goose the device queue if successful.  

	 */

	err = scsi_device_set_state(sdev, SDEV_RUNNING);

	if (err) {

		err = scsi_device_set_state(sdev, SDEV_CREATED);



		if (err)

			return err;

	}



	spin_lock_irqsave(q->queue_lock, flags);

	blk_start_queue(q);

drivers/scsi/scsi_scan.c

+14 −2
Original line number Diff line number Diff line
@@ -730,6 +730,8 @@ static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result, 
static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,

		int *bflags, int async)

{

	int ret;



	/*

	 * XXX do not save the inquiry, since it can change underneath us,

	 * save just vendor/model/rev.
@@ -885,7 +887,17 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result, 


	/* set the device running here so that slave configure

	 * may do I/O */

	scsi_device_set_state(sdev, SDEV_RUNNING);

	ret = scsi_device_set_state(sdev, SDEV_RUNNING);

	if (ret) {

		ret = scsi_device_set_state(sdev, SDEV_BLOCK);



		if (ret) {

			sdev_printk(KERN_ERR, sdev,

				    "in wrong state %s to complete scan\n",

				    scsi_device_state_name(sdev->sdev_state));

			return SCSI_SCAN_NO_RESPONSE;

		}

	}



	if (*bflags & BLIST_MS_192_BYTES_FOR_3F)

		sdev->use_192_bytes_for_3f = 1;
@@ -899,7 +911,7 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result, 
	transport_configure_device(&sdev->sdev_gendev);



	if (sdev->host->hostt->slave_configure) {

		int ret = sdev->host->hostt->slave_configure(sdev);

		ret = sdev->host->hostt->slave_configure(sdev);

		if (ret) {

			/*

			 * if LLDD reports slave not present, don't clutter

drivers/scsi/scsi_sysfs.c

+1 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ static const struct { 
	{ SDEV_QUIESCE, "quiesce" },

	{ SDEV_OFFLINE,	"offline" },

	{ SDEV_BLOCK,	"blocked" },

	{ SDEV_CREATED_BLOCK, "created-blocked" },

};



const char *scsi_device_state_name(enum scsi_device_state state)

include/scsi/scsi_device.h

+9 −5
Original line number Diff line number Diff line
@@ -42,9 +42,11 @@ enum scsi_device_state { 
				 * originate in the mid-layer) */

	SDEV_OFFLINE,		/* Device offlined (by error handling or

				 * user request */

	SDEV_BLOCK,		/* Device blocked by scsi lld.  No scsi 

				 * commands from user or midlayer should be issued

				 * to the scsi lld. */

	SDEV_BLOCK,		/* Device blocked by scsi lld.  No

				 * scsi commands from user or midlayer

				 * should be issued to the scsi

				 * lld. */

	SDEV_CREATED_BLOCK,	/* same as above but for created devices */

};



enum scsi_device_event {
@@ -393,11 +395,13 @@ static inline int scsi_device_online(struct scsi_device *sdev) 
}

static inline int scsi_device_blocked(struct scsi_device *sdev)

{

	return sdev->sdev_state == SDEV_BLOCK;

	return sdev->sdev_state == SDEV_BLOCK ||

		sdev->sdev_state == SDEV_CREATED_BLOCK;

}

static inline int scsi_device_created(struct scsi_device *sdev)

{

	return sdev->sdev_state == SDEV_CREATED;

	return sdev->sdev_state == SDEV_CREATED ||

		sdev->sdev_state == SDEV_CREATED_BLOCK;

}



/* accessor functions for the SCSI parameters */