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Commit a341cd0f authored by Jeff Garzik's avatar Jeff Garzik
Browse files

SCSI: add asynchronous event notification API 



Originally based on a patch by Kristen Carlson Accardi @ Intel.
Copious input from James Bottomley.

Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
parent b4f55508

drivers/scsi/scsi_lib.c

+136 −0
Original line number Diff line number Diff line
@@ -2114,6 +2114,142 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) 
}

EXPORT_SYMBOL(scsi_device_set_state);



/**

 * 	sdev_evt_emit - emit a single SCSI device uevent

 *	@sdev: associated SCSI device

 *	@evt: event to emit

 *

 *	Send a single uevent (scsi_event) to the associated scsi_device.

 */

static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)

{

	int idx = 0;

	char *envp[3];



	switch (evt->evt_type) {

	case SDEV_EVT_MEDIA_CHANGE:

		envp[idx++] = "SDEV_MEDIA_CHANGE=1";

		break;



	default:

		/* do nothing */

		break;

	}



	envp[idx++] = NULL;



	kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);

}



/**

 * 	sdev_evt_thread - send a uevent for each scsi event

 *	@work: work struct for scsi_device

 *

 *	Dispatch queued events to their associated scsi_device kobjects

 *	as uevents.

 */

void scsi_evt_thread(struct work_struct *work)

{

	struct scsi_device *sdev;

	LIST_HEAD(event_list);



	sdev = container_of(work, struct scsi_device, event_work);



	while (1) {

		struct scsi_event *evt;

		struct list_head *this, *tmp;

		unsigned long flags;



		spin_lock_irqsave(&sdev->list_lock, flags);

		list_splice_init(&sdev->event_list, &event_list);

		spin_unlock_irqrestore(&sdev->list_lock, flags);



		if (list_empty(&event_list))

			break;



		list_for_each_safe(this, tmp, &event_list) {

			evt = list_entry(this, struct scsi_event, node);

			list_del(&evt->node);

			scsi_evt_emit(sdev, evt);

			kfree(evt);

		}

	}

}



/**

 * 	sdev_evt_send - send asserted event to uevent thread

 *	@sdev: scsi_device event occurred on

 *	@evt: event to send

 *

 *	Assert scsi device event asynchronously.

 */

void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)

{

	unsigned long flags;



	if (!test_bit(evt->evt_type, sdev->supported_events)) {

		kfree(evt);

		return;

	}



	spin_lock_irqsave(&sdev->list_lock, flags);

	list_add_tail(&evt->node, &sdev->event_list);

	schedule_work(&sdev->event_work);

	spin_unlock_irqrestore(&sdev->list_lock, flags);

}

EXPORT_SYMBOL_GPL(sdev_evt_send);



/**

 * 	sdev_evt_alloc - allocate a new scsi event

 *	@evt_type: type of event to allocate

 *	@gfpflags: GFP flags for allocation

 *

 *	Allocates and returns a new scsi_event.

 */

struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,

				  gfp_t gfpflags)

{

	struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);

	if (!evt)

		return NULL;



	evt->evt_type = evt_type;

	INIT_LIST_HEAD(&evt->node);



	/* evt_type-specific initialization, if any */

	switch (evt_type) {

	case SDEV_EVT_MEDIA_CHANGE:

	default:

		/* do nothing */

		break;

	}



	return evt;

}

EXPORT_SYMBOL_GPL(sdev_evt_alloc);



/**

 * 	sdev_evt_send_simple - send asserted event to uevent thread

 *	@sdev: scsi_device event occurred on

 *	@evt_type: type of event to send

 *	@gfpflags: GFP flags for allocation

 *

 *	Assert scsi device event asynchronously, given an event type.

 */

void sdev_evt_send_simple(struct scsi_device *sdev,

			  enum scsi_device_event evt_type, gfp_t gfpflags)

{

	struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);

	if (!evt) {

		sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",

			    evt_type);

		return;

	}



	sdev_evt_send(sdev, evt);

}

EXPORT_SYMBOL_GPL(sdev_evt_send_simple);



/**

 *	scsi_device_quiesce - Block user issued commands.

 *	@sdev:	scsi device to quiesce.

drivers/scsi/scsi_scan.c

+3 −0
Original line number Diff line number Diff line
@@ -236,6 +236,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget, 
	struct scsi_device *sdev;

	int display_failure_msg = 1, ret;

	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);

	extern void scsi_evt_thread(struct work_struct *work);



	sdev = kzalloc(sizeof(*sdev) + shost->transportt->device_size,

		       GFP_ATOMIC);
@@ -254,7 +255,9 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget, 
	INIT_LIST_HEAD(&sdev->same_target_siblings);

	INIT_LIST_HEAD(&sdev->cmd_list);

	INIT_LIST_HEAD(&sdev->starved_entry);

	INIT_LIST_HEAD(&sdev->event_list);

	spin_lock_init(&sdev->list_lock);

	INIT_WORK(&sdev->event_work, scsi_evt_thread);



	sdev->sdev_gendev.parent = get_device(&starget->dev);

	sdev->sdev_target = starget;

drivers/scsi/scsi_sysfs.c

+47 −0
Original line number Diff line number Diff line
@@ -268,6 +268,7 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work) 
	struct scsi_device *sdev;

	struct device *parent;

	struct scsi_target *starget;

	struct list_head *this, *tmp;

	unsigned long flags;



	sdev = container_of(work, struct scsi_device, ew.work);
@@ -282,6 +283,16 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work) 
	list_del(&sdev->starved_entry);

	spin_unlock_irqrestore(sdev->host->host_lock, flags);



	cancel_work_sync(&sdev->event_work);



	list_for_each_safe(this, tmp, &sdev->event_list) {

		struct scsi_event *evt;



		evt = list_entry(this, struct scsi_event, node);

		list_del(&evt->node);

		kfree(evt);

	}



	if (sdev->request_queue) {

		sdev->request_queue->queuedata = NULL;

		/* user context needed to free queue */
@@ -614,6 +625,41 @@ sdev_show_modalias(struct device *dev, struct device_attribute *attr, char *buf) 
}

static DEVICE_ATTR(modalias, S_IRUGO, sdev_show_modalias, NULL);



#define DECLARE_EVT_SHOW(name, Cap_name)				\

static ssize_t								\

sdev_show_evt_##name(struct device *dev, struct device_attribute *attr,	\

				char *buf)				\

{									\

	struct scsi_device *sdev = to_scsi_device(dev);			\

	int val = test_bit(SDEV_EVT_##Cap_name, sdev->supported_events);\

	return snprintf(buf, 20, "%d\n", val);				\

}



#define DECLARE_EVT_STORE(name, Cap_name)				\

static ssize_t								\

sdev_store_evt_##name(struct device *dev, struct device_attribute *attr, \

		      const char *buf, size_t count)			\

{									\

	struct scsi_device *sdev = to_scsi_device(dev);			\

	int val = simple_strtoul(buf, NULL, 0);				\

	if (val == 0)							\

		clear_bit(SDEV_EVT_##Cap_name, sdev->supported_events);	\

	else if (val == 1)						\

		set_bit(SDEV_EVT_##Cap_name, sdev->supported_events);	\

	else								\

		return -EINVAL;						\

	return count;							\

}



#define DECLARE_EVT(name, Cap_name)					\

	DECLARE_EVT_SHOW(name, Cap_name)				\

	DECLARE_EVT_STORE(name, Cap_name)				\

	static DEVICE_ATTR(evt_##name, S_IRUGO, sdev_show_evt_##name,	\

			   sdev_store_evt_##name);

#define REF_EVT(name) &dev_attr_evt_##name.attr



DECLARE_EVT(media_change, MEDIA_CHANGE)



/* Default template for device attributes.  May NOT be modified */

static struct attribute *scsi_sdev_attrs[] = {

	&dev_attr_device_blocked.attr,
@@ -631,6 +677,7 @@ static struct attribute *scsi_sdev_attrs[] = { 
	&dev_attr_iodone_cnt.attr,

	&dev_attr_ioerr_cnt.attr,

	&dev_attr_modalias.attr,

	REF_EVT(media_change),

	NULL

};

include/scsi/scsi_device.h

+25 −0
Original line number Diff line number Diff line
@@ -46,6 +46,22 @@ enum scsi_device_state { 
				 * to the scsi lld. */

};



enum scsi_device_event {

	SDEV_EVT_MEDIA_CHANGE	= 1,	/* media has changed */



	SDEV_EVT_LAST		= SDEV_EVT_MEDIA_CHANGE,

	SDEV_EVT_MAXBITS	= SDEV_EVT_LAST + 1

};



struct scsi_event {

	enum scsi_device_event	evt_type;

	struct list_head	node;



	/* put union of data structures, for non-simple event types,

	 * here

	 */

};



struct scsi_device {

	struct Scsi_Host *host;

	struct request_queue *request_queue;
@@ -127,6 +143,10 @@ struct scsi_device { 
	unsigned guess_capacity:1;	/* READ_CAPACITY might be too high by 1 */

	unsigned retry_hwerror:1;	/* Retry HARDWARE_ERROR */



	DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /* supported events */

	struct list_head event_list;	/* asserted events */

	struct work_struct event_work;



	unsigned int device_blocked;	/* Device returned QUEUE_FULL. */



	unsigned int max_device_blocked; /* what device_blocked counts down from  */
@@ -275,6 +295,11 @@ extern int scsi_test_unit_ready(struct scsi_device *sdev, int timeout, 
				int retries);

extern int scsi_device_set_state(struct scsi_device *sdev,

				 enum scsi_device_state state);

extern struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,

					  gfp_t gfpflags);

extern void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt);

extern void sdev_evt_send_simple(struct scsi_device *sdev,

			  enum scsi_device_event evt_type, gfp_t gfpflags);

extern int scsi_device_quiesce(struct scsi_device *sdev);

extern void scsi_device_resume(struct scsi_device *sdev);

extern void scsi_target_quiesce(struct scsi_target *);