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ublk: move ublk_cancel_dev() out of ub->mutex

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[ Upstream commit 85248d670b71d9edda9459ee14fdc85c8e9632c0 ]

ublk_cancel_dev() just calls ublk_cancel_queue() to cancel all pending
io commands after ublk request queue is idle. The only protection is just
the read & write of ubq->nr_io_ready and avoid duplicated command cancel,
so add one per-queue lock with cancel flag for providing this protection,
meantime move ublk_cancel_dev() out of ub->mutex.

Then we needn't to call io_uring_cmd_complete_in_task() to cancel
pending command. And the same cancel logic will be re-used for
cancelable uring command.

This patch basically reverts commit ac5902f84bb5 ("ublk: fix AB-BA lockdep warning").

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20231009093324.957829-4-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Ming Lei 2023-10-09 17:33:18 +08:00 committed by Greg Kroah-Hartman
parent 1c250f2c5f
commit a8555c86f5
1 changed files with 23 additions and 17 deletions
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40
drivers/block/ublk_drv.c
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@ -103,6 +103,9 @@ struct ublk_uring_cmd_pdu {
*/
#define UBLK_IO_FLAG_NEED_GET_DATA 0x08
/* atomic RW with ubq->cancel_lock */
#define UBLK_IO_FLAG_CANCELED 0x80000000
struct ublk_io {
/* userspace buffer address from io cmd */
__u64 addr;
@ -126,6 +129,7 @@ struct ublk_queue {
unsigned int max_io_sz;
bool force_abort;
unsigned short nr_io_ready; /* how many ios setup */
spinlock_t cancel_lock;
struct ublk_device *dev;
struct ublk_io ios[];
};
@ -1045,28 +1049,28 @@ static inline bool ublk_queue_ready(struct ublk_queue *ubq)
return ubq->nr_io_ready == ubq->q_depth;
}
static void ublk_cmd_cancel_cb(struct io_uring_cmd *cmd, unsigned issue_flags)
{
io_uring_cmd_done(cmd, UBLK_IO_RES_ABORT, 0, issue_flags);
}
static void ublk_cancel_queue(struct ublk_queue *ubq)
{
int i;
if (!ublk_queue_ready(ubq))
return;
for (i = 0; i < ubq->q_depth; i++) {
struct ublk_io *io = &ubq->ios[i];
if (io->flags & UBLK_IO_FLAG_ACTIVE)
io_uring_cmd_complete_in_task(io->cmd,
ublk_cmd_cancel_cb);
}
if (io->flags & UBLK_IO_FLAG_ACTIVE) {
bool done;
/* all io commands are canceled */
ubq->nr_io_ready = 0;
spin_lock(&ubq->cancel_lock);
done = !!(io->flags & UBLK_IO_FLAG_CANCELED);
if (!done)
io->flags |= UBLK_IO_FLAG_CANCELED;
spin_unlock(&ubq->cancel_lock);
if (!done)
io_uring_cmd_done(io->cmd,
UBLK_IO_RES_ABORT, 0,
IO_URING_F_UNLOCKED);
}
}
}
/* Cancel all pending commands, must be called after del_gendisk() returns */
@ -1113,7 +1117,6 @@ static void __ublk_quiesce_dev(struct ublk_device *ub)
blk_mq_quiesce_queue(ub->ub_disk->queue);
ublk_wait_tagset_rqs_idle(ub);
ub->dev_info.state = UBLK_S_DEV_QUIESCED;
ublk_cancel_dev(ub);
/* we are going to release task_struct of ubq_daemon and resets
* ->ubq_daemon to NULL. So in monitor_work, check on ubq_daemon causes UAF.
* Besides, monitor_work is not necessary in QUIESCED state since we have
@ -1136,6 +1139,7 @@ static void ublk_quiesce_work_fn(struct work_struct *work)
__ublk_quiesce_dev(ub);
unlock:
mutex_unlock(&ub->mutex);
ublk_cancel_dev(ub);
}
static void ublk_unquiesce_dev(struct ublk_device *ub)
@ -1175,8 +1179,8 @@ static void ublk_stop_dev(struct ublk_device *ub)
put_disk(ub->ub_disk);
ub->ub_disk = NULL;
unlock:
ublk_cancel_dev(ub);
mutex_unlock(&ub->mutex);
ublk_cancel_dev(ub);
cancel_delayed_work_sync(&ub->monitor_work);
}
@ -1353,6 +1357,7 @@ static int ublk_init_queue(struct ublk_device *ub, int q_id)
void *ptr;
int size;
spin_lock_init(&ubq->cancel_lock);
ubq->flags = ub->dev_info.flags;
ubq->q_id = q_id;
ubq->q_depth = ub->dev_info.queue_depth;
@ -1882,8 +1887,9 @@ static void ublk_queue_reinit(struct ublk_device *ub, struct ublk_queue *ubq)
int i;
WARN_ON_ONCE(!(ubq->ubq_daemon && ubq_daemon_is_dying(ubq)));
/* All old ioucmds have to be completed */
WARN_ON_ONCE(ubq->nr_io_ready);
ubq->nr_io_ready = 0;
/* old daemon is PF_EXITING, put it now */
put_task_struct(ubq->ubq_daemon);
/* We have to reset it to NULL, otherwise ub won't accept new FETCH_REQ */