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ublk: move device reset into ublk_ch_release()

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ublk_ch_release() is called after ublk char device is closed, when all
uring_cmd are done, so it is perfect fine to move ublk device reset to
ublk_ch_release() from ublk_ctrl_start_recovery().

This way can avoid to grab the exiting daemon task_struct too long.

However, reset of the following ublk IO flags has to be moved until ublk
io_uring queues are ready:

- ubq->canceling

For requeuing IO in case of ublk_nosrv_dev_should_queue_io() before device
is recovered

- ubq->fail_io

For failing IO in case of UBLK_F_USER_RECOVERY_FAIL_IO before device is
recovered

- ublk_io->flags

For preventing using io->cmd

With this way, recovery is simplified a lot.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250416035444.99569-5-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei 2025-04-16 11:54:38 +08:00 committed by Jens Axboe
parent 7e26cb69c5
commit 728cbac5fe
1 changed files with 72 additions and 49 deletions
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121
drivers/block/ublk_drv.c
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@ -1074,7 +1074,7 @@ static inline struct ublk_uring_cmd_pdu *ublk_get_uring_cmd_pdu(
static inline bool ubq_daemon_is_dying(struct ublk_queue *ubq)
{
return ubq->ubq_daemon->flags & PF_EXITING;
return !ubq->ubq_daemon || ubq->ubq_daemon->flags & PF_EXITING;
}
/* todo: handle partial completion */
@ -1470,6 +1470,37 @@ static const struct blk_mq_ops ublk_mq_ops = {
.timeout = ublk_timeout,
};
static void ublk_queue_reinit(struct ublk_device *ub, struct ublk_queue *ubq)
{
int i;
/* All old ioucmds have to be completed */
ubq->nr_io_ready = 0;
/*
* old daemon is PF_EXITING, put it now
*
* It could be NULL in case of closing one quisced device.
*/
if (ubq->ubq_daemon)
put_task_struct(ubq->ubq_daemon);
/* We have to reset it to NULL, otherwise ub won't accept new FETCH_REQ */
ubq->ubq_daemon = NULL;
ubq->timeout = false;
for (i = 0; i < ubq->q_depth; i++) {
struct ublk_io *io = &ubq->ios[i];
/*
* UBLK_IO_FLAG_CANCELED is kept for avoiding to touch
* io->cmd
*/
io->flags &= UBLK_IO_FLAG_CANCELED;
io->cmd = NULL;
io->addr = 0;
}
}
static int ublk_ch_open(struct inode *inode, struct file *filp)
{
struct ublk_device *ub = container_of(inode->i_cdev,
@ -1481,10 +1512,26 @@ static int ublk_ch_open(struct inode *inode, struct file *filp)
return 0;
}
static void ublk_reset_ch_dev(struct ublk_device *ub)
{
int i;
for (i = 0; i < ub->dev_info.nr_hw_queues; i++)
ublk_queue_reinit(ub, ublk_get_queue(ub, i));
/* set to NULL, otherwise new ubq_daemon cannot mmap the io_cmd_buf */
ub->mm = NULL;
ub->nr_queues_ready = 0;
ub->nr_privileged_daemon = 0;
}
static int ublk_ch_release(struct inode *inode, struct file *filp)
{
struct ublk_device *ub = filp->private_data;
/* all uring_cmd has been done now, reset device & ubq */
ublk_reset_ch_dev(ub);
clear_bit(UB_STATE_OPEN, &ub->state);
return 0;
}
@ -1831,6 +1878,24 @@ static void ublk_nosrv_work(struct work_struct *work)
ublk_cancel_dev(ub);
}
/* reset ublk io_uring queue & io flags */
static void ublk_reset_io_flags(struct ublk_device *ub)
{
int i, j;
for (i = 0; i < ub->dev_info.nr_hw_queues; i++) {
struct ublk_queue *ubq = ublk_get_queue(ub, i);
/* UBLK_IO_FLAG_CANCELED can be cleared now */
spin_lock(&ubq->cancel_lock);
for (j = 0; j < ubq->q_depth; j++)
ubq->ios[j].flags &= ~UBLK_IO_FLAG_CANCELED;
spin_unlock(&ubq->cancel_lock);
ubq->canceling = false;
ubq->fail_io = false;
}
}
/* device can only be started after all IOs are ready */
static void ublk_mark_io_ready(struct ublk_device *ub, struct ublk_queue *ubq)
__must_hold(&ub->mutex)
@ -1844,8 +1909,12 @@ static void ublk_mark_io_ready(struct ublk_device *ub, struct ublk_queue *ubq)
if (capable(CAP_SYS_ADMIN))
ub->nr_privileged_daemon++;
}
if (ub->nr_queues_ready == ub->dev_info.nr_hw_queues)
if (ub->nr_queues_ready == ub->dev_info.nr_hw_queues) {
/* now we are ready for handling ublk io request */
ublk_reset_io_flags(ub);
complete_all(&ub->completion);
}
}
static void ublk_handle_need_get_data(struct ublk_device *ub, int q_id,
@ -2954,41 +3023,14 @@ static int ublk_ctrl_set_params(struct ublk_device *ub,
return ret;
}
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 */
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 */
ubq->ubq_daemon = NULL;
ubq->timeout = false;
for (i = 0; i < ubq->q_depth; i++) {
struct ublk_io *io = &ubq->ios[i];
/* forget everything now and be ready for new FETCH_REQ */
io->flags = 0;
io->cmd = NULL;
io->addr = 0;
}
}
static int ublk_ctrl_start_recovery(struct ublk_device *ub,
const struct ublksrv_ctrl_cmd *header)
{
int ret = -EINVAL;
int i;
mutex_lock(&ub->mutex);
if (ublk_nosrv_should_stop_dev(ub))
goto out_unlock;
if (!ub->nr_queues_ready)
goto out_unlock;
/*
* START_RECOVERY is only allowd after:
*
@ -3012,12 +3054,6 @@ static int ublk_ctrl_start_recovery(struct ublk_device *ub,
goto out_unlock;
}
pr_devel("%s: start recovery for dev id %d.\n", __func__, header->dev_id);
for (i = 0; i < ub->dev_info.nr_hw_queues; i++)
ublk_queue_reinit(ub, ublk_get_queue(ub, i));
/* set to NULL, otherwise new ubq_daemon cannot mmap the io_cmd_buf */
ub->mm = NULL;
ub->nr_queues_ready = 0;
ub->nr_privileged_daemon = 0;
init_completion(&ub->completion);
ret = 0;
out_unlock:
@ -3030,7 +3066,6 @@ static int ublk_ctrl_end_recovery(struct ublk_device *ub,
{
int ublksrv_pid = (int)header->data[0];
int ret = -EINVAL;
int i;
pr_devel("%s: Waiting for new ubq_daemons(nr: %d) are ready, dev id %d...\n",
__func__, ub->dev_info.nr_hw_queues, header->dev_id);
@ -3050,22 +3085,10 @@ static int ublk_ctrl_end_recovery(struct ublk_device *ub,
goto out_unlock;
}
ub->dev_info.ublksrv_pid = ublksrv_pid;
ub->dev_info.state = UBLK_S_DEV_LIVE;
pr_devel("%s: new ublksrv_pid %d, dev id %d\n",
__func__, ublksrv_pid, header->dev_id);
blk_mq_quiesce_queue(ub->ub_disk->queue);
ub->dev_info.state = UBLK_S_DEV_LIVE;
for (i = 0; i < ub->dev_info.nr_hw_queues; i++) {
struct ublk_queue *ubq = ublk_get_queue(ub, i);
ubq->canceling = false;
ubq->fail_io = false;
}
blk_mq_unquiesce_queue(ub->ub_disk->queue);
pr_devel("%s: queue unquiesced, dev id %d.\n",
__func__, header->dev_id);
blk_mq_kick_requeue_list(ub->ub_disk->queue);
ret = 0;
out_unlock:
mutex_unlock(&ub->mutex);