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Diffstat (limited to 'fs/io_uring.c')
-rw-r--r--fs/io_uring.c347
1 files changed, 265 insertions, 82 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 94a02e076382..31bf68aaa4a4 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -487,6 +487,7 @@ enum {
REQ_F_COMP_LOCKED_BIT,
REQ_F_NEED_CLEANUP_BIT,
REQ_F_OVERFLOW_BIT,
+ REQ_F_POLLED_BIT,
};
enum {
@@ -529,6 +530,13 @@ enum {
REQ_F_NEED_CLEANUP = BIT(REQ_F_NEED_CLEANUP_BIT),
/* in overflow list */
REQ_F_OVERFLOW = BIT(REQ_F_OVERFLOW_BIT),
+ /* already went through poll handler */
+ REQ_F_POLLED = BIT(REQ_F_POLLED_BIT),
+};
+
+struct async_poll {
+ struct io_poll_iocb poll;
+ struct io_wq_work work;
};
/*
@@ -562,27 +570,29 @@ struct io_kiocb {
u8 opcode;
struct io_ring_ctx *ctx;
- union {
- struct list_head list;
- struct hlist_node hash_node;
- };
- struct list_head link_list;
+ struct list_head list;
unsigned int flags;
refcount_t refs;
+ struct task_struct *task;
u64 user_data;
u32 result;
u32 sequence;
+ struct list_head link_list;
+
struct list_head inflight_entry;
union {
/*
* Only commands that never go async can use the below fields,
- * obviously. Right now only IORING_OP_POLL_ADD uses them.
+ * obviously. Right now only IORING_OP_POLL_ADD uses them, and
+ * async armed poll handlers for regular commands. The latter
+ * restore the work, if needed.
*/
struct {
- struct task_struct *task;
struct callback_head task_work;
+ struct hlist_node hash_node;
+ struct async_poll *apoll;
};
struct io_wq_work work;
};
@@ -3569,9 +3579,209 @@ out:
#endif
}
-static bool io_poll_remove_one(struct io_kiocb *req)
+struct io_poll_table {
+ struct poll_table_struct pt;
+ struct io_kiocb *req;
+ int error;
+};
+
+static void __io_queue_proc(struct io_poll_iocb *poll, struct io_poll_table *pt,
+ struct wait_queue_head *head)
+{
+ if (unlikely(poll->head)) {
+ pt->error = -EINVAL;
+ return;
+ }
+
+ pt->error = 0;
+ poll->head = head;
+ add_wait_queue(head, &poll->wait);
+}
+
+static void io_async_queue_proc(struct file *file, struct wait_queue_head *head,
+ struct poll_table_struct *p)
+{
+ struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
+
+ __io_queue_proc(&pt->req->apoll->poll, pt, head);
+}
+
+static int __io_async_wake(struct io_kiocb *req, struct io_poll_iocb *poll,
+ __poll_t mask, task_work_func_t func)
+{
+ struct task_struct *tsk;
+
+ /* for instances that support it check for an event match first: */
+ if (mask && !(mask & poll->events))
+ return 0;
+
+ trace_io_uring_task_add(req->ctx, req->opcode, req->user_data, mask);
+
+ list_del_init(&poll->wait.entry);
+
+ tsk = req->task;
+ req->result = mask;
+ init_task_work(&req->task_work, func);
+ /*
+ * If this fails, then the task is exiting. If that is the case, then
+ * the exit check will ultimately cancel these work items. Hence we
+ * don't need to check here and handle it specifically.
+ */
+ task_work_add(tsk, &req->task_work, true);
+ wake_up_process(tsk);
+ return 1;
+}
+
+static void io_async_task_func(struct callback_head *cb)
+{
+ struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
+ struct async_poll *apoll = req->apoll;
+ struct io_ring_ctx *ctx = req->ctx;
+
+ trace_io_uring_task_run(req->ctx, req->opcode, req->user_data);
+
+ WARN_ON_ONCE(!list_empty(&req->apoll->poll.wait.entry));
+
+ if (hash_hashed(&req->hash_node)) {
+ spin_lock_irq(&ctx->completion_lock);
+ hash_del(&req->hash_node);
+ spin_unlock_irq(&ctx->completion_lock);
+ }
+
+ /* restore ->work in case we need to retry again */
+ memcpy(&req->work, &apoll->work, sizeof(req->work));
+
+ __set_current_state(TASK_RUNNING);
+ mutex_lock(&ctx->uring_lock);
+ __io_queue_sqe(req, NULL);
+ mutex_unlock(&ctx->uring_lock);
+
+ kfree(apoll);
+}
+
+static int io_async_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
+ void *key)
+{
+ struct io_kiocb *req = wait->private;
+ struct io_poll_iocb *poll = &req->apoll->poll;
+
+ trace_io_uring_poll_wake(req->ctx, req->opcode, req->user_data,
+ key_to_poll(key));
+
+ return __io_async_wake(req, poll, key_to_poll(key), io_async_task_func);
+}
+
+static void io_poll_req_insert(struct io_kiocb *req)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+ struct hlist_head *list;
+
+ list = &ctx->cancel_hash[hash_long(req->user_data, ctx->cancel_hash_bits)];
+ hlist_add_head(&req->hash_node, list);
+}
+
+static __poll_t __io_arm_poll_handler(struct io_kiocb *req,
+ struct io_poll_iocb *poll,
+ struct io_poll_table *ipt, __poll_t mask,
+ wait_queue_func_t wake_func)
+ __acquires(&ctx->completion_lock)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+ bool cancel = false;
+
+ poll->file = req->file;
+ poll->head = NULL;
+ poll->done = poll->canceled = false;
+ poll->events = mask;
+
+ ipt->pt._key = mask;
+ ipt->req = req;
+ ipt->error = -EINVAL;
+
+ INIT_LIST_HEAD(&poll->wait.entry);
+ init_waitqueue_func_entry(&poll->wait, wake_func);
+ poll->wait.private = req;
+
+ mask = vfs_poll(req->file, &ipt->pt) & poll->events;
+
+ spin_lock_irq(&ctx->completion_lock);
+ if (likely(poll->head)) {
+ spin_lock(&poll->head->lock);
+ if (unlikely(list_empty(&poll->wait.entry))) {
+ if (ipt->error)
+ cancel = true;
+ ipt->error = 0;
+ mask = 0;
+ }
+ if (mask || ipt->error)
+ list_del_init(&poll->wait.entry);
+ else if (cancel)
+ WRITE_ONCE(poll->canceled, true);
+ else if (!poll->done) /* actually waiting for an event */
+ io_poll_req_insert(req);
+ spin_unlock(&poll->head->lock);
+ }
+
+ return mask;
+}
+
+static bool io_arm_poll_handler(struct io_kiocb *req)
+{
+ const struct io_op_def *def = &io_op_defs[req->opcode];
+ struct io_ring_ctx *ctx = req->ctx;
+ struct async_poll *apoll;
+ struct io_poll_table ipt;
+ __poll_t mask, ret;
+
+ if (!req->file || !file_can_poll(req->file))
+ return false;
+ if (req->flags & (REQ_F_MUST_PUNT | REQ_F_POLLED))
+ return false;
+ if (!def->pollin && !def->pollout)
+ return false;
+
+ apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
+ if (unlikely(!apoll))
+ return false;
+
+ req->flags |= REQ_F_POLLED;
+ memcpy(&apoll->work, &req->work, sizeof(req->work));
+
+ /*
+ * Don't need a reference here, as we're adding it to the task
+ * task_works list. If the task exits, the list is pruned.
+ */
+ req->task = current;
+ req->apoll = apoll;
+ INIT_HLIST_NODE(&req->hash_node);
+
+ if (def->pollin)
+ mask = POLLIN | POLLRDNORM;
+ if (def->pollout)
+ mask |= POLLOUT | POLLWRNORM;
+ mask |= POLLERR | POLLPRI;
+
+ ipt.pt._qproc = io_async_queue_proc;
+
+ ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask,
+ io_async_wake);
+ if (ret) {
+ ipt.error = 0;
+ apoll->poll.done = true;
+ spin_unlock_irq(&ctx->completion_lock);
+ memcpy(&req->work, &apoll->work, sizeof(req->work));
+ kfree(apoll);
+ return false;
+ }
+ spin_unlock_irq(&ctx->completion_lock);
+ trace_io_uring_poll_arm(ctx, req->opcode, req->user_data, mask,
+ apoll->poll.events);
+ return true;
+}
+
+static bool __io_poll_remove_one(struct io_kiocb *req,
+ struct io_poll_iocb *poll)
{
- struct io_poll_iocb *poll = &req->poll;
bool do_complete = false;
spin_lock(&poll->head->lock);
@@ -3581,7 +3791,24 @@ static bool io_poll_remove_one(struct io_kiocb *req)
do_complete = true;
}
spin_unlock(&poll->head->lock);
+ return do_complete;
+}
+
+static bool io_poll_remove_one(struct io_kiocb *req)
+{
+ bool do_complete;
+
+ if (req->opcode == IORING_OP_POLL_ADD) {
+ do_complete = __io_poll_remove_one(req, &req->poll);
+ } else {
+ /* non-poll requests have submit ref still */
+ do_complete = __io_poll_remove_one(req, &req->apoll->poll);
+ if (do_complete)
+ io_put_req(req);
+ }
+
hash_del(&req->hash_node);
+
if (do_complete) {
io_cqring_fill_event(req, -ECANCELED);
io_commit_cqring(req->ctx);
@@ -3704,51 +3931,16 @@ static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
{
struct io_kiocb *req = wait->private;
struct io_poll_iocb *poll = &req->poll;
- __poll_t mask = key_to_poll(key);
- struct task_struct *tsk;
-
- /* for instances that support it check for an event match first: */
- if (mask && !(mask & poll->events))
- return 0;
-
- list_del_init(&poll->wait.entry);
- tsk = req->task;
- req->result = mask;
- init_task_work(&req->task_work, io_poll_task_func);
- task_work_add(tsk, &req->task_work, true);
- wake_up_process(tsk);
- return 1;
+ return __io_async_wake(req, poll, key_to_poll(key), io_poll_task_func);
}
-struct io_poll_table {
- struct poll_table_struct pt;
- struct io_kiocb *req;
- int error;
-};
-
static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
struct poll_table_struct *p)
{
struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
- if (unlikely(pt->req->poll.head)) {
- pt->error = -EINVAL;
- return;
- }
-
- pt->error = 0;
- pt->req->poll.head = head;
- add_wait_queue(head, &pt->req->poll.wait);
-}
-
-static void io_poll_req_insert(struct io_kiocb *req)
-{
- struct io_ring_ctx *ctx = req->ctx;
- struct hlist_head *list;
-
- list = &ctx->cancel_hash[hash_long(req->user_data, ctx->cancel_hash_bits)];
- hlist_add_head(&req->hash_node, list);
+ __io_queue_proc(&pt->req->poll, pt, head);
}
static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
@@ -3766,7 +3958,10 @@ static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe
events = READ_ONCE(sqe->poll_events);
poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP;
- /* task will wait for requests on exit, don't need a ref */
+ /*
+ * Don't need a reference here, as we're adding it to the task
+ * task_works list. If the task exits, the list is pruned.
+ */
req->task = current;
return 0;
}
@@ -3776,46 +3971,15 @@ static int io_poll_add(struct io_kiocb *req, struct io_kiocb **nxt)
struct io_poll_iocb *poll = &req->poll;
struct io_ring_ctx *ctx = req->ctx;
struct io_poll_table ipt;
- bool cancel = false;
__poll_t mask;
INIT_HLIST_NODE(&req->hash_node);
-
- poll->head = NULL;
- poll->done = false;
- poll->canceled = false;
-
- ipt.pt._qproc = io_poll_queue_proc;
- ipt.pt._key = poll->events;
- ipt.req = req;
- ipt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */
-
- /* initialized the list so that we can do list_empty checks */
- INIT_LIST_HEAD(&poll->wait.entry);
- init_waitqueue_func_entry(&poll->wait, io_poll_wake);
- poll->wait.private = req;
-
INIT_LIST_HEAD(&req->list);
+ ipt.pt._qproc = io_poll_queue_proc;
- mask = vfs_poll(poll->file, &ipt.pt) & poll->events;
+ mask = __io_arm_poll_handler(req, &req->poll, &ipt, poll->events,
+ io_poll_wake);
- spin_lock_irq(&ctx->completion_lock);
- if (likely(poll->head)) {
- spin_lock(&poll->head->lock);
- if (unlikely(list_empty(&poll->wait.entry))) {
- if (ipt.error)
- cancel = true;
- ipt.error = 0;
- mask = 0;
- }
- if (mask || ipt.error)
- list_del_init(&poll->wait.entry);
- else if (cancel)
- WRITE_ONCE(poll->canceled, true);
- else if (!poll->done) /* actually waiting for an event */
- io_poll_req_insert(req);
- spin_unlock(&poll->head->lock);
- }
if (mask) { /* no async, we'd stolen it */
ipt.error = 0;
io_poll_complete(req, mask, 0);
@@ -4760,6 +4924,9 @@ static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
if (!(req->flags & REQ_F_LINK))
return NULL;
+ /* for polled retry, if flag is set, we already went through here */
+ if (req->flags & REQ_F_POLLED)
+ return NULL;
nxt = list_first_entry_or_null(&req->link_list, struct io_kiocb,
link_list);
@@ -4797,6 +4964,11 @@ again:
*/
if (ret == -EAGAIN && (!(req->flags & REQ_F_NOWAIT) ||
(req->flags & REQ_F_MUST_PUNT))) {
+ if (io_arm_poll_handler(req)) {
+ if (linked_timeout)
+ io_queue_linked_timeout(linked_timeout);
+ goto done_req;
+ }
punt:
if (io_op_defs[req->opcode].file_table) {
ret = io_grab_files(req);
@@ -6791,6 +6963,17 @@ static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m)
seq_printf(m, "Personalities:\n");
idr_for_each(&ctx->personality_idr, io_uring_show_cred, m);
}
+ seq_printf(m, "PollList:\n");
+ spin_lock_irq(&ctx->completion_lock);
+ for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
+ struct hlist_head *list = &ctx->cancel_hash[i];
+ struct io_kiocb *req;
+
+ hlist_for_each_entry(req, list, hash_node)
+ seq_printf(m, " op=%d, task_works=%d\n", req->opcode,
+ req->task->task_works != NULL);
+ }
+ spin_unlock_irq(&ctx->completion_lock);
mutex_unlock(&ctx->uring_lock);
}
@@ -7007,7 +7190,7 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p)
p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS |
- IORING_FEAT_CUR_PERSONALITY;
+ IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL;
trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);
return ret;
err: