From: Ming Lei ming.lei@redhat.com
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 --- drivers/block/ublk_drv.c | 121 +++++++++++++++++++++++---------------- 1 file changed, 72 insertions(+), 49 deletions(-)
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 9345a6d8dbd8..c619df880c72 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -1043,7 +1043,7 @@ 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 */ @@ -1440,6 +1440,37 @@ 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, @@ -1451,10 +1482,26 @@ 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; } @@ -1801,6 +1848,24 @@ 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) @@ -1814,8 +1879,12 @@ 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 inline int ublk_check_cmd_op(u32 cmd_op) @@ -2866,42 +2935,15 @@ 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, struct io_uring_cmd *cmd) { const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe); 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: * @@ -2925,12 +2967,6 @@ 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: @@ -2944,7 +2980,6 @@ static int ublk_ctrl_end_recovery(struct ublk_device *ub, const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe); 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); @@ -2964,22 +2999,10 @@ 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);