From 1ab1edb0a104dd683d83e7853aa5b624856f4127 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Thu, 16 Jun 2022 10:22:03 +0100 Subject: [PATCH] io_uring: pass poll_find lock back Instead of using implicit knowledge of what is locked or not after io_poll_find() and co returns, pass back a pointer to the locked bucket if any. If set the user must to unlock the spinlock. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/dae1dc5749aa34367812ecf62f82fd3f053aae44.1655371007.git.asml.silence@gmail.com Reviewed-by: Hao Xu Signed-off-by: Jens Axboe --- io_uring/poll.c | 46 ++++++++++++++++++++++++++-------------------- 1 file changed, 26 insertions(+), 20 deletions(-) diff --git a/io_uring/poll.c b/io_uring/poll.c index 1511a26b412d..5b2c6ce26a55 100644 --- a/io_uring/poll.c +++ b/io_uring/poll.c @@ -565,12 +565,15 @@ __cold bool io_poll_remove_all(struct io_ring_ctx *ctx, struct task_struct *tsk, } static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only, - struct io_cancel_data *cd) + struct io_cancel_data *cd, + struct io_hash_bucket **out_bucket) { struct io_kiocb *req; u32 index = hash_long(cd->data, ctx->cancel_hash_bits); struct io_hash_bucket *hb = &ctx->cancel_hash[index]; + *out_bucket = NULL; + spin_lock(&hb->lock); hlist_for_each_entry(req, &hb->list, hash_node) { if (cd->data != req->cqe.user_data) @@ -582,6 +585,7 @@ static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only, continue; req->work.cancel_seq = cd->seq; } + *out_bucket = hb; return req; } spin_unlock(&hb->lock); @@ -589,11 +593,14 @@ static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only, } static struct io_kiocb *io_poll_file_find(struct io_ring_ctx *ctx, - struct io_cancel_data *cd) + struct io_cancel_data *cd, + struct io_hash_bucket **out_bucket) { struct io_kiocb *req; int i; + *out_bucket = NULL; + for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) { struct io_hash_bucket *hb = &ctx->cancel_hash[i]; @@ -605,6 +612,7 @@ static struct io_kiocb *io_poll_file_find(struct io_ring_ctx *ctx, if (cd->seq == req->work.cancel_seq) continue; req->work.cancel_seq = cd->seq; + *out_bucket = hb; return req; } spin_unlock(&hb->lock); @@ -623,23 +631,19 @@ static bool io_poll_disarm(struct io_kiocb *req) int io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd) { + struct io_hash_bucket *bucket; struct io_kiocb *req; - u32 index; - spinlock_t *lock; if (cd->flags & (IORING_ASYNC_CANCEL_FD|IORING_ASYNC_CANCEL_ANY)) - req = io_poll_file_find(ctx, cd); + req = io_poll_file_find(ctx, cd, &bucket); else - req = io_poll_find(ctx, false, cd); - if (!req) { - return -ENOENT; - } else { - index = hash_long(req->cqe.user_data, ctx->cancel_hash_bits); - lock = &ctx->cancel_hash[index].lock; - } - io_poll_cancel_req(req); - spin_unlock(lock); - return 0; + req = io_poll_find(ctx, false, cd, &bucket); + + if (req) + io_poll_cancel_req(req); + if (bucket) + spin_unlock(&bucket->lock); + return req ? 0 : -ENOENT; } static __poll_t io_poll_parse_events(const struct io_uring_sqe *sqe, @@ -732,19 +736,21 @@ int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags) struct io_poll_update *poll_update = io_kiocb_to_cmd(req); struct io_cancel_data cd = { .data = poll_update->old_user_data, }; struct io_ring_ctx *ctx = req->ctx; - u32 index = hash_long(cd.data, ctx->cancel_hash_bits); - spinlock_t *lock = &ctx->cancel_hash[index].lock; + struct io_hash_bucket *bucket; struct io_kiocb *preq; int ret2, ret = 0; bool locked; - preq = io_poll_find(ctx, true, &cd); + preq = io_poll_find(ctx, true, &cd, &bucket); + if (preq) + ret2 = io_poll_disarm(preq); + if (bucket) + spin_unlock(&bucket->lock); + if (!preq) { ret = -ENOENT; goto out; } - ret2 = io_poll_disarm(preq); - spin_unlock(lock); if (!ret2) { ret = -EALREADY; goto out; -- 2.25.1