ublk_drv: move ublk_get_device_from_id into ublk_ctrl_uring_cmd

It is annoying for each control command handler to get/put ublk
device and deal with failure.

Control command handler is simplified a lot by moving
ublk_get_device_from_id into ublk_ctrl_uring_cmd().

Reviewed-by: ZiyangZhang <ZiyangZhang@linux.alibaba.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230106041711.914434-4-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 8a6f38cc62db2eeb5a8983887cffdab52a6fa5c6..b015e46b59bbcee700a7a9afc8373f4ec784efad 100644 (file)
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -1496,21 +1496,16 @@ static struct ublk_device *ublk_get_device_from_id(int idx)
        return ub;
 }
 
-static int ublk_ctrl_start_dev(struct io_uring_cmd *cmd)
+static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd)
 {
        struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
        int ublksrv_pid = (int)header->data[0];
-       struct ublk_device *ub;
        struct gendisk *disk;
        int ret = -EINVAL;
 
        if (ublksrv_pid <= 0)
                return -EINVAL;
 
-       ub = ublk_get_device_from_id(header->dev_id);
-       if (!ub)
-               return -EINVAL;
-
        wait_for_completion_interruptible(&ub->completion);
 
        schedule_delayed_work(&ub->monitor_work, UBLK_DAEMON_MONITOR_PERIOD);
@@ -1559,21 +1554,20 @@ out_put_disk:
                put_disk(disk);
 out_unlock:
        mutex_unlock(&ub->mutex);
-       ublk_put_device(ub);
        return ret;
 }
 
-static int ublk_ctrl_get_queue_affinity(struct io_uring_cmd *cmd)
+static int ublk_ctrl_get_queue_affinity(struct ublk_device *ub,
+               struct io_uring_cmd *cmd)
 {
        struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
        void __user *argp = (void __user *)(unsigned long)header->addr;
-       struct ublk_device *ub;
        cpumask_var_t cpumask;
        unsigned long queue;
        unsigned int retlen;
        unsigned int i;
-       int ret = -EINVAL;
-       
+       int ret;
+
        if (header->len * BITS_PER_BYTE < nr_cpu_ids)
                return -EINVAL;
        if (header->len & (sizeof(unsigned long)-1))
@@ -1581,17 +1575,12 @@ static int ublk_ctrl_get_queue_affinity(struct io_uring_cmd *cmd)
        if (!header->addr)
                return -EINVAL;
 
-       ub = ublk_get_device_from_id(header->dev_id);
-       if (!ub)
-               return -EINVAL;
-
        queue = header->data[0];
        if (queue >= ub->dev_info.nr_hw_queues)
-               goto out_put_device;
+               return -EINVAL;
 
-       ret = -ENOMEM;
        if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL))
-               goto out_put_device;
+               return -ENOMEM;
 
        for_each_possible_cpu(i) {
                if (ub->tag_set.map[HCTX_TYPE_DEFAULT].mq_map[i] == queue)
@@ -1609,8 +1598,6 @@ static int ublk_ctrl_get_queue_affinity(struct io_uring_cmd *cmd)
        ret = 0;
 out_free_cpumask:
        free_cpumask_var(cpumask);
-out_put_device:
-       ublk_put_device(ub);
        return ret;
 }
 
@@ -1731,30 +1718,27 @@ static inline bool ublk_idr_freed(int id)
        return ptr == NULL;
 }
 
-static int ublk_ctrl_del_dev(int idx)
+static int ublk_ctrl_del_dev(struct ublk_device **p_ub)
 {
-       struct ublk_device *ub;
+       struct ublk_device *ub = *p_ub;
+       int idx = ub->ub_number;
        int ret;
 
        ret = mutex_lock_killable(&ublk_ctl_mutex);
        if (ret)
                return ret;
 
-       ub = ublk_get_device_from_id(idx);
-       if (ub) {
-               ublk_remove(ub);
-               ublk_put_device(ub);
-               ret = 0;
-       } else {
-               ret = -ENODEV;
-       }
+       ublk_remove(ub);
+
+       /* Mark the reference as consumed */
+       *p_ub = NULL;
+       ublk_put_device(ub);
 
        /*
         * Wait until the idr is removed, then it can be reused after
         * DEL_DEV command is returned.
         */
-       if (!ret)
-               wait_event(ublk_idr_wq, ublk_idr_freed(idx));
+       wait_event(ublk_idr_wq, ublk_idr_freed(idx));
        mutex_unlock(&ublk_ctl_mutex);
 
        return ret;
@@ -1769,50 +1753,36 @@ static inline void ublk_ctrl_cmd_dump(struct io_uring_cmd *cmd)
                        header->data[0], header->addr, header->len);
 }
 
-static int ublk_ctrl_stop_dev(struct io_uring_cmd *cmd)
+static int ublk_ctrl_stop_dev(struct ublk_device *ub)
 {
-       struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
-       struct ublk_device *ub;
-
-       ub = ublk_get_device_from_id(header->dev_id);
-       if (!ub)
-               return -EINVAL;
-
        ublk_stop_dev(ub);
        cancel_work_sync(&ub->stop_work);
        cancel_work_sync(&ub->quiesce_work);
 
-       ublk_put_device(ub);
        return 0;
 }
 
-static int ublk_ctrl_get_dev_info(struct io_uring_cmd *cmd)
+static int ublk_ctrl_get_dev_info(struct ublk_device *ub,
+               struct io_uring_cmd *cmd)
 {
        struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
        void __user *argp = (void __user *)(unsigned long)header->addr;
-       struct ublk_device *ub;
-       int ret = 0;
 
        if (header->len < sizeof(struct ublksrv_ctrl_dev_info) || !header->addr)
                return -EINVAL;
 
-       ub = ublk_get_device_from_id(header->dev_id);
-       if (!ub)
-               return -EINVAL;
-
        if (copy_to_user(argp, &ub->dev_info, sizeof(ub->dev_info)))
-               ret = -EFAULT;
-       ublk_put_device(ub);
+               return -EFAULT;
 
-       return ret;
+       return 0;
 }
 
-static int ublk_ctrl_get_params(struct io_uring_cmd *cmd)
+static int ublk_ctrl_get_params(struct ublk_device *ub,
+               struct io_uring_cmd *cmd)
 {
        struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
        void __user *argp = (void __user *)(unsigned long)header->addr;
        struct ublk_params_header ph;
-       struct ublk_device *ub;
        int ret;
 
        if (header->len <= sizeof(ph) || !header->addr)
@@ -1827,10 +1797,6 @@ static int ublk_ctrl_get_params(struct io_uring_cmd *cmd)
        if (ph.len > sizeof(struct ublk_params))
                ph.len = sizeof(struct ublk_params);
 
-       ub = ublk_get_device_from_id(header->dev_id);
-       if (!ub)
-               return -EINVAL;
-
        mutex_lock(&ub->mutex);
        if (copy_to_user(argp, &ub->params, ph.len))
                ret = -EFAULT;
@@ -1838,16 +1804,15 @@ static int ublk_ctrl_get_params(struct io_uring_cmd *cmd)
                ret = 0;
        mutex_unlock(&ub->mutex);
 
-       ublk_put_device(ub);
        return ret;
 }
 
-static int ublk_ctrl_set_params(struct io_uring_cmd *cmd)
+static int ublk_ctrl_set_params(struct ublk_device *ub,
+               struct io_uring_cmd *cmd)
 {
        struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
        void __user *argp = (void __user *)(unsigned long)header->addr;
        struct ublk_params_header ph;
-       struct ublk_device *ub;
        int ret = -EFAULT;
 
        if (header->len <= sizeof(ph) || !header->addr)
@@ -1862,10 +1827,6 @@ static int ublk_ctrl_set_params(struct io_uring_cmd *cmd)
        if (ph.len > sizeof(struct ublk_params))
                ph.len = sizeof(struct ublk_params);
 
-       ub = ublk_get_device_from_id(header->dev_id);
-       if (!ub)
-               return -EINVAL;
-
        /* parameters can only be changed when device isn't live */
        mutex_lock(&ub->mutex);
        if (ub->dev_info.state == UBLK_S_DEV_LIVE) {
@@ -1878,7 +1839,6 @@ static int ublk_ctrl_set_params(struct io_uring_cmd *cmd)
                ret = ublk_validate_params(ub);
        }
        mutex_unlock(&ub->mutex);
-       ublk_put_device(ub);
 
        return ret;
 }
@@ -1905,17 +1865,13 @@ static void ublk_queue_reinit(struct ublk_device *ub, struct ublk_queue *ubq)
        }
 }
 
-static int ublk_ctrl_start_recovery(struct io_uring_cmd *cmd)
+static int ublk_ctrl_start_recovery(struct ublk_device *ub,
+               struct io_uring_cmd *cmd)
 {
        struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
-       struct ublk_device *ub;
        int ret = -EINVAL;
        int i;
 
-       ub = ublk_get_device_from_id(header->dev_id);
-       if (!ub)
-               return ret;
-
        mutex_lock(&ub->mutex);
        if (!ublk_can_use_recovery(ub))
                goto out_unlock;
@@ -1948,21 +1904,16 @@ static int ublk_ctrl_start_recovery(struct io_uring_cmd *cmd)
        ret = 0;
  out_unlock:
        mutex_unlock(&ub->mutex);
-       ublk_put_device(ub);
        return ret;
 }
 
-static int ublk_ctrl_end_recovery(struct io_uring_cmd *cmd)
+static int ublk_ctrl_end_recovery(struct ublk_device *ub,
+               struct io_uring_cmd *cmd)
 {
        struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
        int ublksrv_pid = (int)header->data[0];
-       struct ublk_device *ub;
        int ret = -EINVAL;
 
-       ub = ublk_get_device_from_id(header->dev_id);
-       if (!ub)
-               return ret;
-
        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);
        /* wait until new ubq_daemon sending all FETCH_REQ */
@@ -1990,7 +1941,6 @@ static int ublk_ctrl_end_recovery(struct io_uring_cmd *cmd)
        ret = 0;
  out_unlock:
        mutex_unlock(&ub->mutex);
-       ublk_put_device(ub);
        return ret;
 }
 
@@ -1998,6 +1948,7 @@ static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd,
                unsigned int issue_flags)
 {
        struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
+       struct ublk_device *ub = NULL;
        int ret = -EINVAL;
 
        if (issue_flags & IO_URING_F_NONBLOCK)
@@ -2012,41 +1963,50 @@ static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd,
        if (!capable(CAP_SYS_ADMIN))
                goto out;
 
-       ret = -ENODEV;
+       if (cmd->cmd_op != UBLK_CMD_ADD_DEV) {
+               ret = -ENODEV;
+               ub = ublk_get_device_from_id(header->dev_id);
+               if (!ub)
+                       goto out;
+       }
+
        switch (cmd->cmd_op) {
        case UBLK_CMD_START_DEV:
-               ret = ublk_ctrl_start_dev(cmd);
+               ret = ublk_ctrl_start_dev(ub, cmd);
                break;
        case UBLK_CMD_STOP_DEV:
-               ret = ublk_ctrl_stop_dev(cmd);
+               ret = ublk_ctrl_stop_dev(ub);
                break;
        case UBLK_CMD_GET_DEV_INFO:
-               ret = ublk_ctrl_get_dev_info(cmd);
+               ret = ublk_ctrl_get_dev_info(ub, cmd);
                break;
        case UBLK_CMD_ADD_DEV:
                ret = ublk_ctrl_add_dev(cmd);
                break;
        case UBLK_CMD_DEL_DEV:
-               ret = ublk_ctrl_del_dev(header->dev_id);
+               ret = ublk_ctrl_del_dev(&ub);
                break;
        case UBLK_CMD_GET_QUEUE_AFFINITY:
-               ret = ublk_ctrl_get_queue_affinity(cmd);
+               ret = ublk_ctrl_get_queue_affinity(ub, cmd);
                break;
        case UBLK_CMD_GET_PARAMS:
-               ret = ublk_ctrl_get_params(cmd);
+               ret = ublk_ctrl_get_params(ub, cmd);
                break;
        case UBLK_CMD_SET_PARAMS:
-               ret = ublk_ctrl_set_params(cmd);
+               ret = ublk_ctrl_set_params(ub, cmd);
                break;
        case UBLK_CMD_START_USER_RECOVERY:
-               ret = ublk_ctrl_start_recovery(cmd);
+               ret = ublk_ctrl_start_recovery(ub, cmd);
                break;
        case UBLK_CMD_END_USER_RECOVERY:
-               ret = ublk_ctrl_end_recovery(cmd);
+               ret = ublk_ctrl_end_recovery(ub, cmd);
                break;
        default:
+               ret = -ENOTSUPP;
                break;
        }
+       if (ub)
+               ublk_put_device(ub);
  out:
        io_uring_cmd_done(cmd, ret, 0);
        pr_devel("%s: cmd done ret %d cmd_op %x, dev id %d qid %d\n",