[PATCH 4.4 60/60] block: get rid of blk_integrity_revalidate()

From: Greg Kroah-Hartman
Date: Thu May 11 2017 - 10:28:08 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Ilya Dryomov <idryomov@xxxxxxxxx>

commit 19b7ccf8651df09d274671b53039c672a52ad84d upstream.

Commit 25520d55cdb6 ("block: Inline blk_integrity in struct gendisk")
introduced blk_integrity_revalidate(), which seems to assume ownership
of the stable pages flag and unilaterally clears it if no blk_integrity
profile is registered:

if (bi->profile)
disk->queue->backing_dev_info->capabilities |=
BDI_CAP_STABLE_WRITES;
else
disk->queue->backing_dev_info->capabilities &=
~BDI_CAP_STABLE_WRITES;

It's called from revalidate_disk() and rescan_partitions(), making it
impossible to enable stable pages for drivers that support partitions
and don't use blk_integrity: while the call in revalidate_disk() can be
trivially worked around (see zram, which doesn't support partitions and
hence gets away with zram_revalidate_disk()), rescan_partitions() can
be triggered from userspace at any time. This breaks rbd, where the
ceph messenger is responsible for generating/verifying CRCs.

Since blk_integrity_{un,}register() "must" be used for (un)registering
the integrity profile with the block layer, move BDI_CAP_STABLE_WRITES
setting there. This way drivers that call blk_integrity_register() and
use integrity infrastructure won't interfere with drivers that don't
but still want stable pages.

Fixes: 25520d55cdb6 ("block: Inline blk_integrity in struct gendisk")
Cc: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
Tested-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
[idryomov@xxxxxxxxx: backport to < 4.11: bdi is embedded in queue]
Signed-off-by: Jens Axboe <axboe@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
block/blk-integrity.c | 19 ++-----------------
block/partition-generic.c | 1 -
fs/block_dev.c | 1 -
include/linux/genhd.h | 2 --
4 files changed, 2 insertions(+), 21 deletions(-)

--- a/block/blk-integrity.c
+++ b/block/blk-integrity.c
@@ -417,7 +417,7 @@ void blk_integrity_register(struct gendi
bi->tuple_size = template->tuple_size;
bi->tag_size = template->tag_size;

- blk_integrity_revalidate(disk);
+ disk->queue->backing_dev_info.capabilities |= BDI_CAP_STABLE_WRITES;
}
EXPORT_SYMBOL(blk_integrity_register);

@@ -430,26 +430,11 @@ EXPORT_SYMBOL(blk_integrity_register);
*/
void blk_integrity_unregister(struct gendisk *disk)
{
- blk_integrity_revalidate(disk);
+ disk->queue->backing_dev_info.capabilities &= ~BDI_CAP_STABLE_WRITES;
memset(&disk->queue->integrity, 0, sizeof(struct blk_integrity));
}
EXPORT_SYMBOL(blk_integrity_unregister);

-void blk_integrity_revalidate(struct gendisk *disk)
-{
- struct blk_integrity *bi = &disk->queue->integrity;
-
- if (!(disk->flags & GENHD_FL_UP))
- return;
-
- if (bi->profile)
- disk->queue->backing_dev_info.capabilities |=
- BDI_CAP_STABLE_WRITES;
- else
- disk->queue->backing_dev_info.capabilities &=
- ~BDI_CAP_STABLE_WRITES;
-}
-
void blk_integrity_add(struct gendisk *disk)
{
if (kobject_init_and_add(&disk->integrity_kobj, &integrity_ktype,
--- a/block/partition-generic.c
+++ b/block/partition-generic.c
@@ -435,7 +435,6 @@ rescan:

if (disk->fops->revalidate_disk)
disk->fops->revalidate_disk(disk);
- blk_integrity_revalidate(disk);
check_disk_size_change(disk, bdev);
bdev->bd_invalidated = 0;
if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1098,7 +1098,6 @@ int revalidate_disk(struct gendisk *disk

if (disk->fops->revalidate_disk)
ret = disk->fops->revalidate_disk(disk);
- blk_integrity_revalidate(disk);
bdev = bdget_disk(disk, 0);
if (!bdev)
return ret;
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -742,11 +742,9 @@ static inline void part_nr_sects_write(s
#if defined(CONFIG_BLK_DEV_INTEGRITY)
extern void blk_integrity_add(struct gendisk *);
extern void blk_integrity_del(struct gendisk *);
-extern void blk_integrity_revalidate(struct gendisk *);
#else /* CONFIG_BLK_DEV_INTEGRITY */
static inline void blk_integrity_add(struct gendisk *disk) { }
static inline void blk_integrity_del(struct gendisk *disk) { }
-static inline void blk_integrity_revalidate(struct gendisk *disk) { }
#endif /* CONFIG_BLK_DEV_INTEGRITY */

#else /* CONFIG_BLOCK */