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io_uring: pass poll_find lock back

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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 <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/dae1dc5749aa34367812ecf62f82fd3f053aae44.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2022-06-16 10:22:03 +01:00 committed by Jens Axboe
parent 38513c464d
commit 1ab1edb0a1
1 changed files with 26 additions and 20 deletions
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46
io_uring/poll.c
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@ -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;