Commit d4dc210f authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

block: don't block events on excl write for non-optical devices



Disk event code automatically blocks events on excl write.  This is
primarily to avoid issuing polling commands while burning is in
progress.  This behavior doesn't fit other types of devices with
removeable media where polling commands don't have adverse side
effects and door locking usually doesn't exist.

This patch introduces new genhd flag which controls the auto-blocking
behavior and uses it to enable auto-blocking only on optical devices.

Note for stable: 2.6.38 and later only

Cc: stable@kernel.org
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reported-by: default avatarKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
parent 1196f8b8
......@@ -320,6 +320,7 @@ static void pcd_init_units(void)
disk->first_minor = unit;
strcpy(disk->disk_name, cd->name); /* umm... */
disk->fops = &pcd_bdops;
disk->flags = GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE;
disk->events = DISK_EVENT_MEDIA_CHANGE;
}
}
......
......@@ -625,7 +625,8 @@ static int viocd_probe(struct vio_dev *vdev, const struct vio_device_id *id)
blk_queue_max_hw_sectors(q, 4096 / 512);
gendisk->queue = q;
gendisk->fops = &viocd_fops;
gendisk->flags = GENHD_FL_CD|GENHD_FL_REMOVABLE;
gendisk->flags = GENHD_FL_CD | GENHD_FL_REMOVABLE |
GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE;
gendisk->events = DISK_EVENT_MEDIA_CHANGE;
set_capacity(gendisk, 0);
gendisk->private_data = d;
......
......@@ -1781,7 +1781,7 @@ static int ide_cd_probe(ide_drive_t *drive)
ide_cd_read_toc(drive, &sense);
g->fops = &idecd_ops;
g->flags |= GENHD_FL_REMOVABLE;
g->flags |= GENHD_FL_REMOVABLE | GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE;
g->events = DISK_EVENT_MEDIA_CHANGE;
add_disk(g);
return 0;
......
......@@ -636,7 +636,7 @@ static int sr_probe(struct device *dev)
disk->first_minor = minor;
sprintf(disk->disk_name, "sr%d", minor);
disk->fops = &sr_bdops;
disk->flags = GENHD_FL_CD;
disk->flags = GENHD_FL_CD | GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE;
disk->events = DISK_EVENT_MEDIA_CHANGE | DISK_EVENT_EJECT_REQUEST;
blk_queue_rq_timeout(sdev->request_queue, SR_TIMEOUT);
......
......@@ -1237,6 +1237,8 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
res = __blkdev_get(bdev, mode, 0);
if (whole) {
struct gendisk *disk = whole->bd_disk;
/* finish claiming */
mutex_lock(&bdev->bd_mutex);
spin_lock(&bdev_lock);
......@@ -1263,15 +1265,16 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
spin_unlock(&bdev_lock);
/*
* Block event polling for write claims. Any write
* holder makes the write_holder state stick until all
* are released. This is good enough and tracking
* individual writeable reference is too fragile given
* the way @mode is used in blkdev_get/put().
* Block event polling for write claims if requested. Any
* write holder makes the write_holder state stick until
* all are released. This is good enough and tracking
* individual writeable reference is too fragile given the
* way @mode is used in blkdev_get/put().
*/
if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder) {
if ((disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE) &&
!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder) {
bdev->bd_write_holder = true;
disk_block_events(bdev->bd_disk);
disk_block_events(disk);
}
mutex_unlock(&bdev->bd_mutex);
......
......@@ -127,6 +127,7 @@ struct hd_struct {
#define GENHD_FL_SUPPRESS_PARTITION_INFO 32
#define GENHD_FL_EXT_DEVT 64 /* allow extended devt */
#define GENHD_FL_NATIVE_CAPACITY 128
#define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE 256
enum {
DISK_EVENT_MEDIA_CHANGE = 1 << 0, /* media changed */
......
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