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authorLinus Torvalds <torvalds@linux-foundation.org>2020-08-29 02:23:16 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-29 02:23:16 +0300
commit24148d8648e37f8c15bedddfa50d14a31a0582c5 (patch)
tree94195f7e9efaf0ee3d0b50845b059db67972ef59
parent005c53447a63cbce10de37406975a34d7bdc8704 (diff)
parentfdee946d0925f971f167d2606984426763355e4f (diff)
downloadlinux-24148d8648e37f8c15bedddfa50d14a31a0582c5.tar.xz
Merge tag 'io_uring-5.9-2020-08-28' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe: "A few fixes in here, all based on reports and test cases from folks using it. Most of it is stable material as well: - Hashed work cancelation fix (Pavel) - poll wakeup signalfd fix - memlock accounting fix - nonblocking poll retry fix - ensure we never return -ERESTARTSYS for reads - ensure offset == -1 is consistent with preadv2() as documented - IOPOLL -EAGAIN handling fixes - remove useless task_work bounce for block based -EAGAIN retry" * tag 'io_uring-5.9-2020-08-28' of git://git.kernel.dk/linux-block: io_uring: don't bounce block based -EAGAIN retry off task_work io_uring: fix IOPOLL -EAGAIN retries io_uring: clear req->result on IOPOLL re-issue io_uring: make offset == -1 consistent with preadv2/pwritev2 io_uring: ensure read requests go through -ERESTART* transformation io_uring: don't use poll handler if file can't be nonblocking read/written io_uring: fix imbalanced sqo_mm accounting io_uring: revert consumed iov_iter bytes on error io-wq: fix hang after cancelling pending hashed work io_uring: don't recurse on tsk->sighand->siglock with signalfd
-rw-r--r--fs/io-wq.c21
-rw-r--r--fs/io_uring.c99
2 files changed, 76 insertions, 44 deletions
diff --git a/fs/io-wq.c b/fs/io-wq.c
index e92c4724480c..414beb543883 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -925,6 +925,24 @@ static bool io_wq_worker_cancel(struct io_worker *worker, void *data)
return match->nr_running && !match->cancel_all;
}
+static inline void io_wqe_remove_pending(struct io_wqe *wqe,
+ struct io_wq_work *work,
+ struct io_wq_work_node *prev)
+{
+ unsigned int hash = io_get_work_hash(work);
+ struct io_wq_work *prev_work = NULL;
+
+ if (io_wq_is_hashed(work) && work == wqe->hash_tail[hash]) {
+ if (prev)
+ prev_work = container_of(prev, struct io_wq_work, list);
+ if (prev_work && io_get_work_hash(prev_work) == hash)
+ wqe->hash_tail[hash] = prev_work;
+ else
+ wqe->hash_tail[hash] = NULL;
+ }
+ wq_list_del(&wqe->work_list, &work->list, prev);
+}
+
static void io_wqe_cancel_pending_work(struct io_wqe *wqe,
struct io_cb_cancel_data *match)
{
@@ -938,8 +956,7 @@ retry:
work = container_of(node, struct io_wq_work, list);
if (!match->fn(work, match->data))
continue;
-
- wq_list_del(&wqe->work_list, node, prev);
+ io_wqe_remove_pending(wqe, work, prev);
spin_unlock_irqrestore(&wqe->lock, flags);
io_run_cancel(work, wqe);
match->nr_pending++;
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 8a53af8e5fe2..ce69bd9b0838 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1150,7 +1150,7 @@ static void io_prep_async_work(struct io_kiocb *req)
io_req_init_async(req);
if (req->flags & REQ_F_ISREG) {
- if (def->hash_reg_file)
+ if (def->hash_reg_file || (req->ctx->flags & IORING_SETUP_IOPOLL))
io_wq_hash_work(&req->work, file_inode(req->file));
} else {
if (def->unbound_nonreg_file)
@@ -1746,7 +1746,8 @@ static struct io_kiocb *io_req_find_next(struct io_kiocb *req)
return __io_req_find_next(req);
}
-static int io_req_task_work_add(struct io_kiocb *req, struct callback_head *cb)
+static int io_req_task_work_add(struct io_kiocb *req, struct callback_head *cb,
+ bool twa_signal_ok)
{
struct task_struct *tsk = req->task;
struct io_ring_ctx *ctx = req->ctx;
@@ -1759,7 +1760,7 @@ static int io_req_task_work_add(struct io_kiocb *req, struct callback_head *cb)
* will do the job.
*/
notify = 0;
- if (!(ctx->flags & IORING_SETUP_SQPOLL))
+ if (!(ctx->flags & IORING_SETUP_SQPOLL) && twa_signal_ok)
notify = TWA_SIGNAL;
ret = task_work_add(tsk, cb, notify);
@@ -1819,7 +1820,7 @@ static void io_req_task_queue(struct io_kiocb *req)
init_task_work(&req->task_work, io_req_task_submit);
percpu_ref_get(&req->ctx->refs);
- ret = io_req_task_work_add(req, &req->task_work);
+ ret = io_req_task_work_add(req, &req->task_work, true);
if (unlikely(ret)) {
struct task_struct *tsk;
@@ -2048,6 +2049,7 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
req = list_first_entry(done, struct io_kiocb, inflight_entry);
if (READ_ONCE(req->result) == -EAGAIN) {
+ req->result = 0;
req->iopoll_completed = 0;
list_move_tail(&req->inflight_entry, &again);
continue;
@@ -2293,22 +2295,6 @@ end_req:
io_req_complete(req, ret);
return false;
}
-
-static void io_rw_resubmit(struct callback_head *cb)
-{
- struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
- struct io_ring_ctx *ctx = req->ctx;
- int err;
-
- err = io_sq_thread_acquire_mm(ctx, req);
-
- if (io_resubmit_prep(req, err)) {
- refcount_inc(&req->refs);
- io_queue_async_work(req);
- }
-
- percpu_ref_put(&ctx->refs);
-}
#endif
static bool io_rw_reissue(struct io_kiocb *req, long res)
@@ -2319,12 +2305,14 @@ static bool io_rw_reissue(struct io_kiocb *req, long res)
if ((res != -EAGAIN && res != -EOPNOTSUPP) || io_wq_current_is_worker())
return false;
- init_task_work(&req->task_work, io_rw_resubmit);
- percpu_ref_get(&req->ctx->refs);
+ ret = io_sq_thread_acquire_mm(req->ctx, req);
- ret = io_req_task_work_add(req, &req->task_work);
- if (!ret)
+ if (io_resubmit_prep(req, ret)) {
+ refcount_inc(&req->refs);
+ io_queue_async_work(req);
return true;
+ }
+
#endif
return false;
}
@@ -2865,6 +2853,11 @@ static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
return iov_iter_count(&req->io->rw.iter);
}
+static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb)
+{
+ return kiocb->ki_filp->f_mode & FMODE_STREAM ? NULL : &kiocb->ki_pos;
+}
+
/*
* For files that don't have ->read_iter() and ->write_iter(), handle them
* by looping over ->read() or ->write() manually.
@@ -2900,10 +2893,10 @@ static ssize_t loop_rw_iter(int rw, struct file *file, struct kiocb *kiocb,
if (rw == READ) {
nr = file->f_op->read(file, iovec.iov_base,
- iovec.iov_len, &kiocb->ki_pos);
+ iovec.iov_len, io_kiocb_ppos(kiocb));
} else {
nr = file->f_op->write(file, iovec.iov_base,
- iovec.iov_len, &kiocb->ki_pos);
+ iovec.iov_len, io_kiocb_ppos(kiocb));
}
if (iov_iter_is_bvec(iter))
@@ -3044,7 +3037,7 @@ static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode,
/* submit ref gets dropped, acquire a new one */
refcount_inc(&req->refs);
- ret = io_req_task_work_add(req, &req->task_work);
+ ret = io_req_task_work_add(req, &req->task_work, true);
if (unlikely(ret)) {
struct task_struct *tsk;
@@ -3125,6 +3118,7 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
ret = io_import_iovec(READ, req, &iovec, iter, !force_nonblock);
if (ret < 0)
return ret;
+ iov_count = iov_iter_count(iter);
io_size = ret;
req->result = io_size;
ret = 0;
@@ -3137,8 +3131,7 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
if (force_nonblock && !io_file_supports_async(req->file, READ))
goto copy_iov;
- iov_count = iov_iter_count(iter);
- ret = rw_verify_area(READ, req->file, &kiocb->ki_pos, iov_count);
+ ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), iov_count);
if (unlikely(ret))
goto out_free;
@@ -3150,14 +3143,18 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
ret = 0;
goto out_free;
} else if (ret == -EAGAIN) {
- if (!force_nonblock)
+ /* IOPOLL retry should happen for io-wq threads */
+ if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))
goto done;
+ /* some cases will consume bytes even on error returns */
+ iov_iter_revert(iter, iov_count - iov_iter_count(iter));
ret = io_setup_async_rw(req, iovec, inline_vecs, iter, false);
if (ret)
goto out_free;
return -EAGAIN;
} else if (ret < 0) {
- goto out_free;
+ /* make sure -ERESTARTSYS -> -EINTR is done */
+ goto done;
}
/* read it all, or we did blocking attempt. no retry. */
@@ -3241,6 +3238,7 @@ static int io_write(struct io_kiocb *req, bool force_nonblock,
ret = io_import_iovec(WRITE, req, &iovec, iter, !force_nonblock);
if (ret < 0)
return ret;
+ iov_count = iov_iter_count(iter);
io_size = ret;
req->result = io_size;
@@ -3257,8 +3255,7 @@ static int io_write(struct io_kiocb *req, bool force_nonblock,
(req->flags & REQ_F_ISREG))
goto copy_iov;
- iov_count = iov_iter_count(iter);
- ret = rw_verify_area(WRITE, req->file, &kiocb->ki_pos, iov_count);
+ ret = rw_verify_area(WRITE, req->file, io_kiocb_ppos(kiocb), iov_count);
if (unlikely(ret))
goto out_free;
@@ -3291,9 +3288,14 @@ static int io_write(struct io_kiocb *req, bool force_nonblock,
if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
ret2 = -EAGAIN;
if (!force_nonblock || ret2 != -EAGAIN) {
+ /* IOPOLL retry should happen for io-wq threads */
+ if ((req->ctx->flags & IORING_SETUP_IOPOLL) && ret2 == -EAGAIN)
+ goto copy_iov;
kiocb_done(kiocb, ret2, cs);
} else {
copy_iov:
+ /* some cases will consume bytes even on error returns */
+ iov_iter_revert(iter, iov_count - iov_iter_count(iter));
ret = io_setup_async_rw(req, iovec, inline_vecs, iter, false);
if (!ret)
return -EAGAIN;
@@ -4566,6 +4568,7 @@ struct io_poll_table {
static int __io_async_wake(struct io_kiocb *req, struct io_poll_iocb *poll,
__poll_t mask, task_work_func_t func)
{
+ bool twa_signal_ok;
int ret;
/* for instances that support it check for an event match first: */
@@ -4581,12 +4584,20 @@ static int __io_async_wake(struct io_kiocb *req, struct io_poll_iocb *poll,
percpu_ref_get(&req->ctx->refs);
/*
+ * If we using the signalfd wait_queue_head for this wakeup, then
+ * it's not safe to use TWA_SIGNAL as we could be recursing on the
+ * tsk->sighand->siglock on doing the wakeup. Should not be needed
+ * either, as the normal wakeup will suffice.
+ */
+ twa_signal_ok = (poll->head != &req->task->sighand->signalfd_wqh);
+
+ /*
* If this fails, then the task is exiting. When a task exits, the
* work gets canceled, so just cancel this request as well instead
* of executing it. We can't safely execute it anyway, as we may not
* have the needed state needed for it anyway.
*/
- ret = io_req_task_work_add(req, &req->task_work);
+ ret = io_req_task_work_add(req, &req->task_work, twa_signal_ok);
if (unlikely(ret)) {
struct task_struct *tsk;
@@ -4875,12 +4886,20 @@ static bool io_arm_poll_handler(struct io_kiocb *req)
struct async_poll *apoll;
struct io_poll_table ipt;
__poll_t mask, ret;
+ int rw;
if (!req->file || !file_can_poll(req->file))
return false;
if (req->flags & REQ_F_POLLED)
return false;
- if (!def->pollin && !def->pollout)
+ if (def->pollin)
+ rw = READ;
+ else if (def->pollout)
+ rw = WRITE;
+ else
+ return false;
+ /* if we can't nonblock try, then no point in arming a poll handler */
+ if (!io_file_supports_async(req->file, rw))
return false;
apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
@@ -7433,9 +7452,6 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx,
{
int ret;
- mmgrab(current->mm);
- ctx->sqo_mm = current->mm;
-
if (ctx->flags & IORING_SETUP_SQPOLL) {
ret = -EPERM;
if (!capable(CAP_SYS_ADMIN))
@@ -7480,10 +7496,6 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx,
return 0;
err:
io_finish_async(ctx);
- if (ctx->sqo_mm) {
- mmdrop(ctx->sqo_mm);
- ctx->sqo_mm = NULL;
- }
return ret;
}
@@ -8533,6 +8545,9 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
ctx->user = user;
ctx->creds = get_current_cred();
+ mmgrab(current->mm);
+ ctx->sqo_mm = current->mm;
+
/*
* Account memory _before_ installing the file descriptor. Once
* the descriptor is installed, it can get closed at any time. Also