diff options
| author | Ming Lei <ming.lei@redhat.com> | 2023-10-09 17:33:17 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-10-17 08:27:55 -0600 |
| commit | 3421c7f68bba52281bbb38bc76c18dc03cb689e4 (patch) | |
| tree | 797f00777984d521a287b39858ba91d53c9b59ac /drivers/block/ublk_drv.c | |
| parent | 8ed90e370f9b5442a2766b357b92e36bbf6ba82d (diff) | |
ublk: make sure io cmd handled in submitter task context
In well-done ublk server implementation, ublk io command won't be
linked into any link chain. Meantime they are always handled in no-wait
style, so basically io cmd is always handled in submitter task context.
However, the server may set IOSQE_ASYNC, or io command is linked to one
chain mistakenly, then we may still run into io-wq context and
ctx->uring_lock isn't held.
So in case of IO_URING_F_UNLOCKED, schedule this command by
io_uring_cmd_complete_in_task to force running it in submitter task. Then
ublk_ch_uring_cmd_local() is guaranteed to run with context uring_lock held,
and we needn't to worry about sync among submission code path any more.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20231009093324.957829-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block/ublk_drv.c')
| -rw-r--r-- | drivers/block/ublk_drv.c | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 59d3652699f5..2e2efae62c77 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -1811,7 +1811,8 @@ fail_put: return NULL; } -static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags) +static inline int ublk_ch_uring_cmd_local(struct io_uring_cmd *cmd, + unsigned int issue_flags) { /* * Not necessary for async retry, but let's keep it simple and always @@ -1825,9 +1826,28 @@ static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags) .addr = READ_ONCE(ub_src->addr) }; + WARN_ON_ONCE(issue_flags & IO_URING_F_UNLOCKED); + return __ublk_ch_uring_cmd(cmd, issue_flags, &ub_cmd); } +static void ublk_ch_uring_cmd_cb(struct io_uring_cmd *cmd, + unsigned int issue_flags) +{ + ublk_ch_uring_cmd_local(cmd, issue_flags); +} + +static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags) +{ + /* well-implemented server won't run into unlocked */ + if (unlikely(issue_flags & IO_URING_F_UNLOCKED)) { + io_uring_cmd_complete_in_task(cmd, ublk_ch_uring_cmd_cb); + return -EIOCBQUEUED; + } + + return ublk_ch_uring_cmd_local(cmd, issue_flags); +} + static inline bool ublk_check_ubuf_dir(const struct request *req, int ubuf_dir) { |