summaryrefslogtreecommitdiff
path: root/io_uring
diff options
context:
space:
mode:
authorDylan Yudaken <dylany@meta.com>2022-10-27 07:44:29 -0700
committerJens Axboe <axboe@kernel.dk>2022-10-27 09:52:12 -0600
commitb3026767e15b488860d4bbf1649d69612bab2c25 (patch)
tree0331f0cc2950f0b9c4bc0019fb87e2aa51b05ac9 /io_uring
parent8de11cdc96bf58b324c59a28512eb9513fd02553 (diff)
io_uring: unlock if __io_run_local_work locked inside
It is possible for tw to lock the ring, and this was not propogated out to io_run_local_work. This can cause an unlock to be missed. Instead pass a pointer to locked into __io_run_local_work. Fixes: 8ac5d85a89b4 ("io_uring: add local task_work run helper that is entered locked") Signed-off-by: Dylan Yudaken <dylany@meta.com> Link: https://lore.kernel.org/r/20221027144429.3971400-3-dylany@meta.com [axboe: WARN_ON() -> WARN_ON_ONCE() and add a minor comment] Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
-rw-r--r--io_uring/io_uring.c8
-rw-r--r--io_uring/io_uring.h13
2 files changed, 15 insertions, 6 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 8a0ce7379e89..ac8c488e3077 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -1173,7 +1173,7 @@ static void __cold io_move_task_work_from_local(struct io_ring_ctx *ctx)
}
}
-int __io_run_local_work(struct io_ring_ctx *ctx, bool locked)
+int __io_run_local_work(struct io_ring_ctx *ctx, bool *locked)
{
struct llist_node *node;
struct llist_node fake;
@@ -1192,7 +1192,7 @@ again:
struct io_kiocb *req = container_of(node, struct io_kiocb,
io_task_work.node);
prefetch(container_of(next, struct io_kiocb, io_task_work.node));
- req->io_task_work.func(req, &locked);
+ req->io_task_work.func(req, locked);
ret++;
node = next;
}
@@ -1208,7 +1208,7 @@ again:
goto again;
}
- if (locked)
+ if (*locked)
io_submit_flush_completions(ctx);
trace_io_uring_local_work_run(ctx, ret, loops);
return ret;
@@ -1225,7 +1225,7 @@ int io_run_local_work(struct io_ring_ctx *ctx)
__set_current_state(TASK_RUNNING);
locked = mutex_trylock(&ctx->uring_lock);
- ret = __io_run_local_work(ctx, locked);
+ ret = __io_run_local_work(ctx, &locked);
if (locked)
mutex_unlock(&ctx->uring_lock);
diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h
index ef77d2aa3172..e99a79f2df9b 100644
--- a/io_uring/io_uring.h
+++ b/io_uring/io_uring.h
@@ -27,7 +27,7 @@ enum {
struct io_uring_cqe *__io_get_cqe(struct io_ring_ctx *ctx, bool overflow);
bool io_req_cqe_overflow(struct io_kiocb *req);
int io_run_task_work_sig(struct io_ring_ctx *ctx);
-int __io_run_local_work(struct io_ring_ctx *ctx, bool locked);
+int __io_run_local_work(struct io_ring_ctx *ctx, bool *locked);
int io_run_local_work(struct io_ring_ctx *ctx);
void io_req_complete_failed(struct io_kiocb *req, s32 res);
void __io_req_complete(struct io_kiocb *req, unsigned issue_flags);
@@ -277,9 +277,18 @@ static inline int io_run_task_work_ctx(struct io_ring_ctx *ctx)
static inline int io_run_local_work_locked(struct io_ring_ctx *ctx)
{
+ bool locked;
+ int ret;
+
if (llist_empty(&ctx->work_llist))
return 0;
- return __io_run_local_work(ctx, true);
+
+ locked = true;
+ ret = __io_run_local_work(ctx, &locked);
+ /* shouldn't happen! */
+ if (WARN_ON_ONCE(!locked))
+ mutex_lock(&ctx->uring_lock);
+ return ret;
}
static inline void io_tw_lock(struct io_ring_ctx *ctx, bool *locked)