From 8bb649ee1da321ec3a1bbec048a425c5ea18ea21 Mon Sep 17 00:00:00 2001 From: Usama Arif Date: Fri, 4 Feb 2022 14:51:17 +0000 Subject: [PATCH] io_uring: remove ring quiesce for io_uring_register None of the opcodes in io_uring_register use ring quiesce anymore. Hence io_register_op_must_quiesce always returns false and io_ctx_quiesce is never called. Signed-off-by: Usama Arif Link: https://lore.kernel.org/r/20220204145117.1186568-6-usama.arif@bytedance.com Signed-off-by: Jens Axboe --- fs/io_uring.c | 83 --------------------------------------------------- 1 file changed, 83 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 6ff9f67e2a1e..49bcc5fc688d 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1292,18 +1292,6 @@ static inline unsigned int io_put_kbuf(struct io_kiocb *req) return __io_put_kbuf(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, bool cancel_all) __must_hold(&req->ctx->timeout_lock) @@ -11007,66 +10995,6 @@ err: return ret; } -static bool io_register_op_must_quiesce(int op) -{ - switch (op) { - case IORING_REGISTER_BUFFERS: - case IORING_UNREGISTER_BUFFERS: - case IORING_REGISTER_FILES: - case IORING_UNREGISTER_FILES: - case IORING_REGISTER_FILES_UPDATE: - case IORING_REGISTER_EVENTFD: - case IORING_REGISTER_EVENTFD_ASYNC: - case IORING_UNREGISTER_EVENTFD: - case IORING_REGISTER_PROBE: - case IORING_REGISTER_PERSONALITY: - case IORING_UNREGISTER_PERSONALITY: - case IORING_REGISTER_ENABLE_RINGS: - case IORING_REGISTER_RESTRICTIONS: - case IORING_REGISTER_FILES2: - case IORING_REGISTER_FILES_UPDATE2: - case IORING_REGISTER_BUFFERS2: - case IORING_REGISTER_BUFFERS_UPDATE: - case IORING_REGISTER_IOWQ_AFF: - case IORING_UNREGISTER_IOWQ_AFF: - case IORING_REGISTER_IOWQ_MAX_WORKERS: - return false; - default: - return true; - } -} - -static __cold int io_ctx_quiesce(struct io_ring_ctx *ctx) -{ - long ret; - - percpu_ref_kill(&ctx->refs); - - /* - * Drop uring mutex before waiting for references to exit. If another - * thread is currently inside io_uring_enter() it might need to grab the - * uring_lock to make progress. If we hold it here across the drain - * wait, then we can deadlock. It's safe to drop the mutex here, since - * no new references will come in after we've killed the percpu ref. - */ - mutex_unlock(&ctx->uring_lock); - do { - ret = wait_for_completion_interruptible_timeout(&ctx->ref_comp, HZ); - if (ret) { - ret = min(0L, ret); - break; - } - - ret = io_run_task_work_sig(); - io_req_caches_free(ctx); - } while (ret >= 0); - mutex_lock(&ctx->uring_lock); - - if (ret) - io_refs_resurrect(&ctx->refs, &ctx->ref_comp); - return ret; -} - static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, void __user *arg, unsigned nr_args) __releases(ctx->uring_lock) @@ -11090,12 +11018,6 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, return -EACCES; } - if (io_register_op_must_quiesce(opcode)) { - ret = io_ctx_quiesce(ctx); - if (ret) - return ret; - } - switch (opcode) { case IORING_REGISTER_BUFFERS: ret = io_sqe_buffers_register(ctx, arg, nr_args, NULL); @@ -11200,11 +11122,6 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, break; } - if (io_register_op_must_quiesce(opcode)) { - /* bring the ctx back to life */ - percpu_ref_reinit(&ctx->refs); - reinit_completion(&ctx->ref_comp); - } return ret; }