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author | Pavel Begunkov <asml.silence@gmail.com> | 2021-04-11 03:46:40 +0300 |
---|---|---|
committer | Jens Axboe <axboe@kernel.dk> | 2021-04-12 18:33:10 +0300 |
commit | f70865db5ff35f5ed0c7e9ef63e7cca3d4947f04 (patch) | |
tree | 7e9a2ff732e1b21cd4795fcf7ca779f141a7bf37 /fs/io_uring.c | |
parent | e4335ed33eb54ba00c58557753dc84c0ee762ef1 (diff) | |
download | linux-f70865db5ff35f5ed0c7e9ef63e7cca3d4947f04.tar.xz |
io_uring: return back safer resurrect
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>
Diffstat (limited to 'fs/io_uring.c')
-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 15e18c03fba8..8564c7908126 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1081,6 +1081,18 @@ static inline void io_req_set_rsrc_node(struct io_kiocb *req) } } +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) @@ -9788,12 +9800,11 @@ 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; } } @@ -9886,7 +9897,6 @@ 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; |