From: Kristen Carlson Accardi <kristen.c.accardi@xxxxxxxxx>
If a scsi_device supports async notification for media change, then let user
space know this capability exists by creating a new sysfs entry
"media_change_notify", which will be 1 if it is supported, and 0 if not
supported. Create a routine which allows scsi devices to send a uevent when
media change events occur.
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@xxxxxxxxx>
Cc: Jeff Garzik <jeff@xxxxxxxxxx>
Cc: Tejun Heo <htejun@xxxxxxxxx>
Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/scsi/scsi_lib.c | 83 +++++++++++++++++++++++++++++++++++
drivers/scsi/scsi_scan.c | 1
drivers/scsi/scsi_sysfs.c | 13 +++++
include/scsi/scsi_device.h | 15 +++++-
4 files changed, 111 insertions(+), 1 deletion(-)
diff -puN drivers/scsi/scsi_lib.c~scsi-expose-an-support-to-user-space drivers/scsi/scsi_lib.c
--- a/drivers/scsi/scsi_lib.c~scsi-expose-an-support-to-user-space
+++ a/drivers/scsi/scsi_lib.c
@@ -64,6 +64,11 @@ static struct scsi_host_sg_pool scsi_sg_
};
#undef SP
+/* must match scsi_device_event enum in scsi_device.h */
+static char * scsi_device_event_strings[] = {
+ "MEDIA_CHANGE=1",
+};
+
static void scsi_run_queue(struct request_queue *q);
/*
@@ -2007,6 +2012,84 @@ scsi_device_set_state(struct scsi_device
EXPORT_SYMBOL(scsi_device_set_state);
/**
+ * scsi_device_set_event - Add a new Async event to the event list
+ * @sdev: scsi_device event occurred on
+ * @event: the scsi device event
+ *
+ * Add a new scsi_device_event_info struct to the scsi_device_event_list
+ * queue. This may be called from interrupt context.
+ *
+ * Returns 0 if successful, -ENOMEM otherwise.
+ */
+static int
+scsi_device_set_event(struct scsi_device *sdev, enum scsi_device_event event)
+{
+ struct scsi_device_event_info *scsi_event;
+ unsigned long flags;
+
+ scsi_event = kzalloc(sizeof(*scsi_event), GFP_ATOMIC);
+ if (!scsi_event)
+ return -ENOMEM;
+ INIT_LIST_HEAD(&scsi_event->link);
+ scsi_event->event = event;
+ spin_lock_irqsave(&sdev->list_lock, flags);
+ list_add_tail(&scsi_event->link, &sdev->sdev_event_list);
+ spin_unlock_irqrestore(&sdev->list_lock, flags);
+ return 0;
+}
+
+/**
+ * scsi_device_event_notify_thread - send a uevent for each scsi event
+ * @work: work struct for scsi_device
+ *
+ * Traverse the queue of scsi device events, dequeue each event and
+ * send a uevent. Frees event. May not be called from interrupt.
+ */
+static void scsi_event_notify_thread(struct work_struct *work)
+{
+ struct scsi_device *sdev;
+ char *envp[] = { NULL, NULL };
+ struct list_head *tmp;
+ struct list_head *next;
+ struct scsi_device_event_info *sdev_event;
+ unsigned long flags;
+
+ sdev = container_of(work, struct scsi_device, ew.work);
+ list_for_each_safe(tmp, next, &sdev->sdev_event_list) {
+ sdev_event = list_entry(tmp, struct scsi_device_event_info,
+ link);
+ spin_lock_irqsave(&sdev->list_lock, flags);
+ list_del(&sdev_event->link);
+ spin_unlock_irqrestore(&sdev->list_lock, flags);
+ envp[0] = scsi_device_event_strings[sdev_event->event-1];
+ kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
+ kfree(sdev_event);
+ }
+}
+
+/**
+ * scsi_device_event_notify - store event info and send an event
+ * @sdev: scsi_device event occurred on
+ * @event: the scsi device event
+ *
+ * Store the event information and then switch process context
+ * so that the event may be sent to user space.
+ * This may be called from interrupt context.
+ *
+ * Returns 0 if successful, -ENOMEM otherwise.
+ */
+int scsi_device_event_notify(struct scsi_device *sdev, enum scsi_device_event event)
+{
+ int rc;
+
+ rc = scsi_device_set_event(sdev, event);
+ if (!rc)
+ execute_in_process_context(scsi_event_notify_thread, &sdev->ew);
+ return rc;
+}
+EXPORT_SYMBOL_GPL(scsi_device_event_notify);
+
+/**
* scsi_device_quiesce - Block user issued commands.
* @sdev: scsi device to quiesce.
*
diff -puN drivers/scsi/scsi_scan.c~scsi-expose-an-support-to-user-space drivers/scsi/scsi_scan.c
--- a/drivers/scsi/scsi_scan.c~scsi-expose-an-support-to-user-space
+++ a/drivers/scsi/scsi_scan.c
@@ -253,6 +253,7 @@ static struct scsi_device *scsi_alloc_sd
INIT_LIST_HEAD(&sdev->same_target_siblings);
INIT_LIST_HEAD(&sdev->cmd_list);
INIT_LIST_HEAD(&sdev->starved_entry);
+ INIT_LIST_HEAD(&sdev->sdev_event_list);
spin_lock_init(&sdev->list_lock);
sdev->sdev_gendev.parent = get_device(&starget->dev);
diff -puN drivers/scsi/scsi_sysfs.c~scsi-expose-an-support-to-user-space drivers/scsi/scsi_sysfs.c
--- a/drivers/scsi/scsi_sysfs.c~scsi-expose-an-support-to-user-space
+++ a/drivers/scsi/scsi_sysfs.c
@@ -570,6 +570,18 @@ sdev_show_modalias(struct device *dev, s
}
static DEVICE_ATTR(modalias, S_IRUGO, sdev_show_modalias, NULL);
+static ssize_t
+sdev_show_media_change_notify(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct scsi_device *sdev = to_scsi_device(dev);
+ if (sdev->media_change_notify)
+ return snprintf(buf, 20, "%d\n", 1);
+ else
+ return snprintf(buf, 20, "%d\n", 0);
+}
+static DEVICE_ATTR(media_change_notify, S_IRUGO, sdev_show_media_change_notify, NULL);
+
/* Default template for device attributes. May NOT be modified */
static struct device_attribute *scsi_sysfs_sdev_attrs[] = {
&dev_attr_device_blocked,
@@ -589,6 +601,7 @@ static struct device_attribute *scsi_sys
&dev_attr_iodone_cnt,
&dev_attr_ioerr_cnt,
&dev_attr_modalias,
+ &dev_attr_media_change_notify,
NULL
};
diff -puN include/scsi/scsi_device.h~scsi-expose-an-support-to-user-space include/scsi/scsi_device.h
--- a/include/scsi/scsi_device.h~scsi-expose-an-support-to-user-space
+++ a/include/scsi/scsi_device.h
@@ -46,6 +46,16 @@ enum scsi_device_state {
* to the scsi lld. */
};
+/* must match scsi_device_event_strings in scsi_lib.c */
+enum scsi_device_event {
+ SDEV_MEDIA_CHANGE = 1, /* media has changed */
+};
+
+struct scsi_device_event_info {
+ enum scsi_device_event event;
+ struct list_head link;
+};
+
struct scsi_device {
struct Scsi_Host *host;
struct request_queue *request_queue;
@@ -126,7 +136,7 @@ struct scsi_device {
unsigned fix_capacity:1; /* READ_CAPACITY is too high by 1 */
unsigned guess_capacity:1; /* READ_CAPACITY might be too high by 1 */
unsigned retry_hwerror:1; /* Retry HARDWARE_ERROR */
-
+ unsigned media_change_notify:1; /* dev supports async media notify */
unsigned int device_blocked; /* Device returned QUEUE_FULL. */
unsigned int max_device_blocked; /* what device_blocked counts down from */
@@ -144,6 +154,7 @@ struct scsi_device {
struct execute_work ew; /* used to get process context on put */
enum scsi_device_state sdev_state;
+ struct list_head sdev_event_list;
unsigned long sdev_data[0];
} __attribute__((aligned(sizeof(unsigned long))));
#define to_scsi_device(d) \
@@ -275,6 +286,8 @@ extern int scsi_test_unit_ready(struct s
int retries);
extern int scsi_device_set_state(struct scsi_device *sdev,
enum scsi_device_state state);
+extern int scsi_device_event_notify(struct scsi_device *sdev,
+ enum scsi_device_event event);
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 *);
_
-
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