From: Bart Van Assche Date: Fri, 10 May 2024 20:23:11 +0000 (-0700) Subject: nbd: Improve the documentation of the locking assumptions X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=2a6751e052ab4789630bc889c814037068723bc1;p=linux.git nbd: Improve the documentation of the locking assumptions Document locking assumptions with lockdep_assert_held() instead of source code comments. The advantage of lockdep_assert_held() is that it is verified at runtime if lockdep is enabled in the kernel config. Cc: Christoph Hellwig Cc: Josef Bacik Cc: Yu Kuai Cc: Markus Pargmann Signed-off-by: Bart Van Assche Link: https://lore.kernel.org/r/20240510202313.25209-4-bvanassche@acm.org Signed-off-by: Jens Axboe --- diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 90760f27824df..05f69710afe80 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -588,7 +588,6 @@ static inline int was_interrupted(int result) return result == -ERESTARTSYS || result == -EINTR; } -/* always call with the tx_lock held */ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) { struct request *req = blk_mq_rq_from_pdu(cmd); @@ -605,6 +604,9 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) u32 nbd_cmd_flags = 0; int sent = nsock->sent, skip = 0; + lockdep_assert_held(&cmd->lock); + lockdep_assert_held(&nsock->tx_lock); + iov_iter_kvec(&from, ITER_SOURCE, &iov, 1, sizeof(request)); type = req_to_nbd_cmd_type(req); @@ -1015,6 +1017,8 @@ static int nbd_handle_cmd(struct nbd_cmd *cmd, int index) struct nbd_sock *nsock; int ret; + lockdep_assert_held(&cmd->lock); + config = nbd_get_config_unlocked(nbd); if (!config) { dev_err_ratelimited(disk_to_dev(nbd->disk),