diff options
| author | Pavel Begunkov <asml.silence@gmail.com> | 2021-04-11 01:46:40 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-19 13:44:46 +0100 |
| commit | dc1163203ae6e24b86168390fe5b4a3295fcba7f (patch) | |
| tree | 85127b43db49e411cadba99ece576030c13c0098 | |
| parent | 8fdaab341bad8a8449fcdca349e5081e6f62db09 (diff) | |
io_uring: return back safer resurrect
commit f70865db5ff35f5ed0c7e9ef63e7cca3d4947f04 upstream.
Revert of revert of "io_uring: wait potential ->release() on resurrect",
which adds a helper for resurrect not racing completion reinit, as was
removed because of a strange bug with no clear root or link to the
patch.
Was improved, instead of rcu_synchronize(), just wait_for_completion()
because we're at 0 refs and it will happen very shortly. Specifically
use non-interruptible version to ignore all pending signals that may
have ended prior interruptible wait.
This reverts commit cb5e1b81304e089ee3ca948db4d29f71902eb575.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/7a080c20f686d026efade810b116b72f88abaff9.1618101759.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cc: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/io_uring.c | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 019cbde8c3d6..fd188b972151 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1009,6 +1009,18 @@ static inline bool __io_match_files(struct io_kiocb *req, req->work.identity->files == files; } +static void io_refs_resurrect(struct percpu_ref *ref, struct completion *compl) +{ + bool got = percpu_ref_tryget(ref); + + /* already at zero, wait for ->release() */ + if (!got) + wait_for_completion(compl); + percpu_ref_resurrect(ref); + if (got) + percpu_ref_put(ref); +} + static bool io_match_task(struct io_kiocb *head, struct task_struct *task, struct files_struct *files) @@ -9757,12 +9769,11 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, if (ret < 0) break; } while (1); - mutex_lock(&ctx->uring_lock); if (ret) { - percpu_ref_resurrect(&ctx->refs); - goto out_quiesce; + io_refs_resurrect(&ctx->refs, &ctx->ref_comp); + return ret; } } @@ -9855,7 +9866,6 @@ out: if (io_register_op_must_quiesce(opcode)) { /* bring the ctx back to life */ percpu_ref_reinit(&ctx->refs); -out_quiesce: reinit_completion(&ctx->ref_comp); } return ret; |