@@ -1904,6 +1904,9 @@ static ssize_t disk_events_poll_msecs_show(struct device *dev,
{
struct gendisk *disk = dev_to_disk(dev);
+ if (!disk->ev)
+ return sprintf(buf, "-1\n");
+
return sprintf(buf, "%ld\n", disk->ev->poll_msecs);
}
@@ -1920,6 +1923,9 @@ static ssize_t disk_events_poll_msecs_store(struct device *dev,
if (intv < 0 && intv != -1)
return -EINVAL;
+ if (!disk->ev)
+ return -ENODEV;
+
disk_block_events(disk);
disk->ev->poll_msecs = intv;
__disk_unblock_events(disk, true);
@@ -1984,7 +1990,7 @@ static void disk_alloc_events(struct gendisk *disk)
{
struct disk_events *ev;
- if (!disk->fops->check_events)
+ if (!disk->fops->check_events || !disk->events)
return;
ev = kzalloc(sizeof(*ev), GFP_KERNEL);
@@ -2006,14 +2012,14 @@ static void disk_alloc_events(struct gendisk *disk)
static void disk_add_events(struct gendisk *disk)
{
- if (!disk->ev)
- return;
-
/* FIXME: error handling */
if (sysfs_create_files(&disk_to_dev(disk)->kobj, disk_events_attrs) < 0)
pr_warn("%s: failed to create sysfs files for events\n",
disk->disk_name);
+ if (!disk->ev)
+ return;
+
mutex_lock(&disk_events_mutex);
list_add_tail(&disk->ev->node, &disk_events);
mutex_unlock(&disk_events_mutex);
@@ -2027,14 +2033,13 @@ static void disk_add_events(struct gendisk *disk)
static void disk_del_events(struct gendisk *disk)
{
- if (!disk->ev)
- return;
+ if (disk->ev) {
+ disk_block_events(disk);
- disk_block_events(disk);
-
- mutex_lock(&disk_events_mutex);
- list_del_init(&disk->ev->node);
- mutex_unlock(&disk_events_mutex);
+ mutex_lock(&disk_events_mutex);
+ list_del_init(&disk->ev->node);
+ mutex_unlock(&disk_events_mutex);
+ }
sysfs_remove_files(&disk_to_dev(disk)->kobj, disk_events_attrs);
}
Drivers now report to the block layer if they support media change events. If this is not the case, there's no need to allocate the event structure, and all event handling code can effectively be skipped. This simplifies code flow in particular for non-removable sd devices. This effectively reverts commit 75e3f3ee3c64 ("block: always allocate genhd->ev if check_events is implemented"). The sysfs files for the events are kept in place even if no events are supported, as user space may rely on them being present. The only difference is that an error code is now returned if the user tries to set poll_msecs. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin Wilck <mwilck@suse.com> --- block/genhd.c | 27 ++++++++++++++++----------- 1 file changed, 16 insertions(+), 11 deletions(-)