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Commit 172edde9 authored by Linus Torvalds's avatar Linus Torvalds
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Merge tag 'io_uring-5.7-2020-04-09' of git://git.kernel.dk/linux-block 

Pull io_uring fixes from Jens Axboe:
 "Here's a set of fixes that either weren't quite ready for the first,
  or came about from some intensive testing on memcached with 350K+
  sockets.

  Summary:

   - Fixes for races or deadlocks around poll handling

   - Don't double account fixed files against RLIMIT_NOFILE

   - IORING_OP_OPENAT LFS fix

   - Poll retry handling (Bijan)

   - Missing finish_wait() for SQPOLL (Hillf)

   - Cleanup/split of io_kiocb alloc vs ctx references (Pavel)

   - Fixed file unregistration and init fixes (Xiaoguang)

   - Various little fixes (Xiaoguang, Pavel, Colin)"

* tag 'io_uring-5.7-2020-04-09' of git://git.kernel.dk/linux-block:
  io_uring: punt final io_ring_ctx wait-and-free to workqueue
  io_uring: fix fs cleanup on cqe overflow
  io_uring: don't read user-shared sqe flags twice
  io_uring: remove req init from io_get_req()
  io_uring: alloc req only after getting sqe
  io_uring: simplify io_get_sqring
  io_uring: do not always copy iovec in io_req_map_rw()
  io_uring: ensure openat sets O_LARGEFILE if needed
  io_uring: initialize fixed_file_data lock
  io_uring: remove redundant variable pointer nxt and io_wq_assign_next call
  io_uring: fix ctx refcounting in io_submit_sqes()
  io_uring: process requests completed with -EAGAIN on poll list
  io_uring: remove bogus RLIMIT_NOFILE check in file registration
  io_uring: use io-wq manager as backup task if task is exiting
  io_uring: grab task reference for poll requests
  io_uring: retry poll if we got woken with non-matching mask
  io_uring: add missing finish_wait() in io_sq_thread()
  io_uring: refactor file register/unregister/update handling
parents 8c3c0743 85faa7b8
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Showing with 269 additions and 173 deletions
fs/io-wq.c
View file @ 172edde9
......@@ -17,6 +17,7 @@
#include <linux/kthread.h>
#include <linux/rculist_nulls.h>
#include <linux/fs_struct.h>
#include <linux/task_work.h>
#include "io-wq.h"
......@@ -716,6 +717,9 @@ static int io_wq_manager(void *data)
complete(&wq->done);
while (!kthread_should_stop()) {
if (current->task_works)
task_work_run();
for_each_node(node) {
struct io_wqe *wqe = wq->wqes[node];
bool fork_worker[2] = { false, false };
......@@ -738,6 +742,9 @@ static int io_wq_manager(void *data)
schedule_timeout(HZ);
}
if (current->task_works)
task_work_run();
return 0;
err:
set_bit(IO_WQ_BIT_ERROR, &wq->state);
......@@ -1124,3 +1131,8 @@ void io_wq_destroy(struct io_wq *wq)
if (refcount_dec_and_test(&wq->use_refs))
__io_wq_destroy(wq);
}
struct task_struct *io_wq_get_task(struct io_wq *wq)
{
return wq->manager;
}
fs/io-wq.h
View file @ 172edde9
......@@ -136,6 +136,8 @@ typedef bool (work_cancel_fn)(struct io_wq_work *, void *);
enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
void *data);
struct task_struct *io_wq_get_task(struct io_wq *wq);
#if defined(CONFIG_IO_WQ)
extern void io_wq_worker_sleeping(struct task_struct *);
extern void io_wq_worker_running(struct task_struct *);
......
fs/io_uring.c
View file @ 172edde9
......@@ -186,14 +186,23 @@ struct fixed_file_table {
struct file **files;
};
struct fixed_file_ref_node {
struct percpu_ref refs;
struct list_head node;
struct list_head file_list;
struct fixed_file_data *file_data;
struct work_struct work;
};
struct fixed_file_data {
struct fixed_file_table *table;
struct io_ring_ctx *ctx;
struct percpu_ref *cur_refs;
struct percpu_ref refs;
struct llist_head put_llist;
struct work_struct ref_work;
struct completion done;
struct list_head ref_list;
spinlock_t lock;
};
struct io_buffer {
......@@ -317,6 +326,8 @@ struct io_ring_ctx {
spinlock_t inflight_lock;
struct list_head inflight_list;
} ____cacheline_aligned_in_smp;
struct work_struct exit_work;
};
/*
......@@ -599,6 +610,7 @@ struct io_kiocb {
};
struct io_async_ctx *io;
int cflags;
bool needs_fixed_file;
u8 opcode;
......@@ -606,10 +618,8 @@ struct io_kiocb {
struct list_head list;
unsigned int flags;
refcount_t refs;
union {
struct task_struct *task;
unsigned long fsize;
};
u64 user_data;
u32 result;
u32 sequence;
......@@ -618,6 +628,8 @@ struct io_kiocb {
struct list_head inflight_entry;
struct percpu_ref *fixed_file_refs;
union {
/*
* Only commands that never go async can use the below fields,
......@@ -629,7 +641,6 @@ struct io_kiocb {
struct callback_head task_work;
struct hlist_node hash_node;
struct async_poll *apoll;
int cflags;
};
struct io_wq_work work;
};
......@@ -848,7 +859,6 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
struct io_uring_files_update *ip,
unsigned nr_args);
static int io_grab_files(struct io_kiocb *req);
static void io_ring_file_ref_flush(struct fixed_file_data *data);
static void io_cleanup_req(struct io_kiocb *req);
static int io_file_get(struct io_submit_state *state, struct io_kiocb *req,
int fd, struct file **out_file, bool fixed);
......@@ -1285,7 +1295,7 @@ static struct io_kiocb *io_get_fallback_req(struct io_ring_ctx *ctx)
return NULL;
}
static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx,
static struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx,
struct io_submit_state *state)
{
gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
......@@ -1319,41 +1329,20 @@ static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx,
req = state->reqs[state->free_reqs];
}
got_it:
req->io = NULL;
req->file = NULL;
req->ctx = ctx;
req->flags = 0;
/* one is dropped after submission, the other at completion */
refcount_set(&req->refs, 2);
req->result = 0;
INIT_IO_WORK(&req->work, io_wq_submit_work);
return req;
fallback:
req = io_get_fallback_req(ctx);
if (req)
goto got_it;
percpu_ref_put(&ctx->refs);
return NULL;
return io_get_fallback_req(ctx);
}
static inline void io_put_file(struct io_kiocb *req, struct file *file,
bool fixed)
{
if (fixed)
percpu_ref_put(&req->ctx->file_data->refs);
percpu_ref_put(req->fixed_file_refs);
else
fput(file);
}
static void __io_req_do_free(struct io_kiocb *req)
{
if (likely(!io_is_fallback_req(req)))
kmem_cache_free(req_cachep, req);
else
clear_bit_unlock(0, (unsigned long *) req->ctx->fallback_req);
}
static void __io_req_aux_free(struct io_kiocb *req)
{
if (req->flags & REQ_F_NEED_CLEANUP)
......@@ -1362,6 +1351,8 @@ static void __io_req_aux_free(struct io_kiocb *req)
kfree(req->io);
if (req->file)
io_put_file(req, req->file, (req->flags & REQ_F_FIXED_FILE));
if (req->task)
put_task_struct(req->task);
io_req_work_drop_env(req);
}
......@@ -1382,7 +1373,10 @@ static void __io_free_req(struct io_kiocb *req)
}
percpu_ref_put(&req->ctx->refs);
__io_req_do_free(req);
if (likely(!io_is_fallback_req(req)))
kmem_cache_free(req_cachep, req);
else
clear_bit_unlock(0, (unsigned long *) req->ctx->fallback_req);
}
struct req_batch {
......@@ -1393,21 +1387,18 @@ struct req_batch {
static void io_free_req_many(struct io_ring_ctx *ctx, struct req_batch *rb)
{
int fixed_refs = rb->to_free;
if (!rb->to_free)
return;
if (rb->need_iter) {
int i, inflight = 0;
unsigned long flags;
fixed_refs = 0;
for (i = 0; i < rb->to_free; i++) {
struct io_kiocb *req = rb->reqs[i];
if (req->flags & REQ_F_FIXED_FILE) {
req->file = NULL;
fixed_refs++;
percpu_ref_put(req->fixed_file_refs);
}
if (req->flags & REQ_F_INFLIGHT)
inflight++;
......@@ -1433,8 +1424,6 @@ static void io_free_req_many(struct io_ring_ctx *ctx, struct req_batch *rb)
}
do_free:
kmem_cache_free_bulk(req_cachep, rb->to_free, rb->reqs);
if (fixed_refs)
percpu_ref_put_many(&ctx->file_data->refs, fixed_refs);
percpu_ref_put_many(&ctx->refs, rb->to_free);
rb->to_free = rb->need_iter = 0;
}
......@@ -1738,11 +1727,24 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
io_free_req_many(ctx, &rb);
}
static void io_iopoll_queue(struct list_head *again)
{
struct io_kiocb *req;
do {
req = list_first_entry(again, struct io_kiocb, list);
list_del(&req->list);
refcount_inc(&req->refs);
io_queue_async_work(req);
} while (!list_empty(again));
}
static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
long min)
{
struct io_kiocb *req, *tmp;
LIST_HEAD(done);
LIST_HEAD(again);
bool spin;
int ret;
......@@ -1757,9 +1759,9 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
struct kiocb *kiocb = &req->rw.kiocb;
/*
* Move completed entries to our local list. If we find a
* request that requires polling, break out and complete
* the done list first, if we have entries there.
* Move completed and retryable entries to our local lists.
* If we find a request that requires polling, break out
* and complete those lists first, if we have entries there.
*/
if (req->flags & REQ_F_IOPOLL_COMPLETED) {
list_move_tail(&req->list, &done);
......@@ -1768,6 +1770,13 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
if (!list_empty(&done))
break;
if (req->result == -EAGAIN) {
list_move_tail(&req->list, &again);
continue;
}
if (!list_empty(&again))
break;
ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin);
if (ret < 0)
break;
......@@ -1780,6 +1789,9 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
if (!list_empty(&done))
io_iopoll_complete(ctx, nr_events, &done);
if (!list_empty(&again))
io_iopoll_queue(&again);
return ret;
}
......@@ -2465,6 +2477,7 @@ static void io_req_map_rw(struct io_kiocb *req, ssize_t io_size,
req->io->rw.iov = iovec;
if (!req->io->rw.iov) {
req->io->rw.iov = req->io->rw.fast_iov;
if (req->io->rw.iov != fast_iov)
memcpy(req->io->rw.iov, fast_iov,
sizeof(struct iovec) * iter->nr_segs);
} else {
......@@ -2920,7 +2933,7 @@ static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
if (sqe->ioprio || sqe->buf_index)
return -EINVAL;
if (sqe->flags & IOSQE_FIXED_FILE)
if (req->flags & REQ_F_FIXED_FILE)
return -EBADF;
if (req->flags & REQ_F_NEED_CLEANUP)
return 0;
......@@ -2929,6 +2942,8 @@ static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
req->open.how.mode = READ_ONCE(sqe->len);
fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
req->open.how.flags = READ_ONCE(sqe->open_flags);
if (force_o_largefile())
req->open.how.flags |= O_LARGEFILE;
req->open.filename = getname(fname);
if (IS_ERR(req->open.filename)) {
......@@ -2951,7 +2966,7 @@ static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
if (sqe->ioprio || sqe->buf_index)
return -EINVAL;
if (sqe->flags & IOSQE_FIXED_FILE)
if (req->flags & REQ_F_FIXED_FILE)
return -EBADF;
if (req->flags & REQ_F_NEED_CLEANUP)
return 0;
......@@ -3305,7 +3320,7 @@ static int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
if (sqe->ioprio || sqe->buf_index)
return -EINVAL;
if (sqe->flags & IOSQE_FIXED_FILE)
if (req->flags & REQ_F_FIXED_FILE)
return -EBADF;
if (req->flags & REQ_F_NEED_CLEANUP)
return 0;
......@@ -3382,7 +3397,7 @@ static int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
if (sqe->ioprio || sqe->off || sqe->addr || sqe->len ||
sqe->rw_flags || sqe->buf_index)
return -EINVAL;
if (sqe->flags & IOSQE_FIXED_FILE)
if (req->flags & REQ_F_FIXED_FILE)
return -EBADF;
req->close.fd = READ_ONCE(sqe->fd);
......@@ -3481,14 +3496,11 @@ static void __io_sync_file_range(struct io_kiocb *req)
static void io_sync_file_range_finish(struct io_wq_work **workptr)
{
struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work);
struct io_kiocb *nxt = NULL;
if (io_req_cancelled(req))
return;
__io_sync_file_range(req);
io_put_req(req); /* put submission ref */
if (nxt)
io_wq_assign_next(workptr, nxt);
}
static int io_sync_file_range(struct io_kiocb *req, bool force_nonblock)
......@@ -4114,6 +4126,7 @@ 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;
int ret;
/* for instances that support it check for an event match first: */
if (mask && !(mask & poll->events))
......@@ -4127,11 +4140,15 @@ static int __io_async_wake(struct io_kiocb *req, struct io_poll_iocb *poll,
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.
* If this fails, then the task is exiting. Punt to one of the io-wq
* threads to ensure the work gets run, we can't always rely on exit
* cancelation taking care of this.
*/
ret = task_work_add(tsk, &req->task_work, true);
if (unlikely(ret)) {
tsk = io_wq_get_task(req->ctx->io_wq);
task_work_add(tsk, &req->task_work, true);
}
wake_up_process(tsk);
return 1;
}
......@@ -4251,10 +4268,7 @@ static bool io_arm_poll_handler(struct io_kiocb *req)
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.
*/
get_task_struct(current);
req->task = current;
req->apoll = apoll;
INIT_HLIST_NODE(&req->hash_node);
......@@ -4407,8 +4421,20 @@ static void io_poll_complete(struct io_kiocb *req, __poll_t mask, int error)
static void io_poll_task_handler(struct io_kiocb *req, struct io_kiocb **nxt)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_poll_iocb *poll = &req->poll;
if (!req->result && !READ_ONCE(poll->canceled)) {
struct poll_table_struct pt = { ._key = poll->events };
req->result = vfs_poll(req->file, &pt) & poll->events;
}
spin_lock_irq(&ctx->completion_lock);
if (!req->result && !READ_ONCE(poll->canceled)) {
add_wait_queue(poll->head, &poll->wait);
spin_unlock_irq(&ctx->completion_lock);
return;
}
hash_del(&req->hash_node);
io_poll_complete(req, req->result, 0);
req->flags |= REQ_F_COMP_LOCKED;
......@@ -4465,10 +4491,7 @@ 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;
/*
* 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.
*/
get_task_struct(current);
req->task = current;
return 0;
}
......@@ -5331,7 +5354,8 @@ static int io_file_get(struct io_submit_state *state, struct io_kiocb *req,
file = io_file_from_index(ctx, fd);
if (!file)
return -EBADF;
percpu_ref_get(&ctx->file_data->refs);
req->fixed_file_refs = ctx->file_data->cur_refs;
percpu_ref_get(req->fixed_file_refs);
} else {
trace_io_uring_file_get(ctx, fd);
file = __io_file_get(state, fd);
......@@ -5344,15 +5368,10 @@ static int io_file_get(struct io_submit_state *state, struct io_kiocb *req,
}
static int io_req_set_file(struct io_submit_state *state, struct io_kiocb *req,
const struct io_uring_sqe *sqe)
int fd, unsigned int flags)
{
unsigned flags;
int fd;
bool fixed;
flags = READ_ONCE(sqe->flags);
fd = READ_ONCE(sqe->fd);
if (!io_req_needs_file(req, fd))
return 0;
......@@ -5594,7 +5613,7 @@ static bool io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
{
struct io_ring_ctx *ctx = req->ctx;
unsigned int sqe_flags;
int ret, id;
int ret, id, fd;
sqe_flags = READ_ONCE(sqe->flags);
......@@ -5625,7 +5644,8 @@ static bool io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
IOSQE_ASYNC | IOSQE_FIXED_FILE |
IOSQE_BUFFER_SELECT);
ret = io_req_set_file(state, req, sqe);
fd = READ_ONCE(sqe->fd);
ret = io_req_set_file(state, req, fd, sqe_flags);
if (unlikely(ret)) {
err_req:
io_cqring_add_event(req, ret);
......@@ -5741,8 +5761,7 @@ static void io_commit_sqring(struct io_ring_ctx *ctx)
* used, it's important that those reads are done through READ_ONCE() to
* prevent a re-load down the line.
*/
static bool io_get_sqring(struct io_ring_ctx *ctx, struct io_kiocb *req,
const struct io_uring_sqe **sqe_ptr)
static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx)
{
u32 *sq_array = ctx->sq_array;
unsigned head;
......@@ -5756,25 +5775,40 @@ static bool io_get_sqring(struct io_ring_ctx *ctx, struct io_kiocb *req,
* though the application is the one updating it.
*/
head = READ_ONCE(sq_array[ctx->cached_sq_head & ctx->sq_mask]);
if (likely(head < ctx->sq_entries)) {
if (likely(head < ctx->sq_entries))
return &ctx->sq_sqes[head];
/* drop invalid entries */
ctx->cached_sq_dropped++;
WRITE_ONCE(ctx->rings->sq_dropped, ctx->cached_sq_dropped);
return NULL;
}
static inline void io_consume_sqe(struct io_ring_ctx *ctx)
{
ctx->cached_sq_head++;
}
static void io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
/*
* All io need record the previous position, if LINK vs DARIN,
* it can be used to mark the position of the first IO in the
* link list.
*/
req->sequence = ctx->cached_sq_head;
*sqe_ptr = &ctx->sq_sqes[head];
req->opcode = READ_ONCE((*sqe_ptr)->opcode);
req->user_data = READ_ONCE((*sqe_ptr)->user_data);
ctx->cached_sq_head++;
return true;
}
/* drop invalid entries */
ctx->cached_sq_head++;
ctx->cached_sq_dropped++;
WRITE_ONCE(ctx->rings->sq_dropped, ctx->cached_sq_dropped);
return false;
req->opcode = READ_ONCE(sqe->opcode);
req->user_data = READ_ONCE(sqe->user_data);
req->io = NULL;
req->file = NULL;
req->ctx = ctx;
req->flags = 0;
/* one is dropped after submission, the other at completion */
refcount_set(&req->refs, 2);
req->task = NULL;
req->result = 0;
INIT_IO_WORK(&req->work, io_wq_submit_work);
}
static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
......@@ -5812,17 +5846,20 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
struct io_kiocb *req;
int err;
req = io_get_req(ctx, statep);
sqe = io_get_sqe(ctx);
if (unlikely(!sqe)) {
io_consume_sqe(ctx);
break;
}
req = io_alloc_req(ctx, statep);
if (unlikely(!req)) {
if (!submitted)
submitted = -EAGAIN;
break;
}
if (!io_get_sqring(ctx, req, &sqe)) {
__io_req_do_free(req);
break;
}
io_init_req(ctx, req, sqe);
io_consume_sqe(ctx);
/* will complete beyond this point, count as submitted */
submitted++;
......@@ -5962,6 +5999,7 @@ static int io_sq_thread(void *data)
}
if (current->task_works) {
task_work_run();
finish_wait(&ctx->sqo_wait, &wait);
continue;
}
if (signal_pending(current))
......@@ -6124,43 +6162,36 @@ static void io_file_ref_kill(struct percpu_ref *ref)
complete(&data->done);
}
static void io_file_ref_exit_and_free(struct work_struct *work)
{
struct fixed_file_data *data;
data = container_of(work, struct fixed_file_data, ref_work);
/*
* Ensure any percpu-ref atomic switch callback has run, it could have
* been in progress when the files were being unregistered. Once
* that's done, we can safely exit and free the ref and containing
* data structure.
*/
rcu_barrier();
percpu_ref_exit(&data->refs);
kfree(data);
}
static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
{
struct fixed_file_data *data = ctx->file_data;
struct fixed_file_ref_node *ref_node = NULL;
unsigned nr_tables, i;
unsigned long flags;
if (!data)
return -ENXIO;
percpu_ref_kill_and_confirm(&data->refs, io_file_ref_kill);
flush_work(&data->ref_work);
spin_lock_irqsave(&data->lock, flags);
if (!list_empty(&data->ref_list))
ref_node = list_first_entry(&data->ref_list,
struct fixed_file_ref_node, node);
spin_unlock_irqrestore(&data->lock, flags);
if (ref_node)
percpu_ref_kill(&ref_node->refs);
percpu_ref_kill(&data->refs);
/* wait for all refs nodes to complete */
wait_for_completion(&data->done);
io_ring_file_ref_flush(data);
__io_sqe_files_unregister(ctx);
nr_tables = DIV_ROUND_UP(ctx->nr_user_files, IORING_MAX_FILES_TABLE);
for (i = 0; i < nr_tables; i++)
kfree(data->table[i].files);
kfree(data->table);
INIT_WORK(&data->ref_work, io_file_ref_exit_and_free);
queue_work(system_wq, &data->ref_work);
percpu_ref_exit(&data->refs);
kfree(data);
ctx->file_data = NULL;
ctx->nr_user_files = 0;
return 0;
......@@ -6204,13 +6235,6 @@ static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int nr, int offset)
struct sk_buff *skb;
int i, nr_files;
if (!capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) {
unsigned long inflight = ctx->user->unix_inflight + nr;
if (inflight > task_rlimit(current, RLIMIT_NOFILE))
return -EMFILE;
}
fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
if (!fpl)
return -ENOMEM;
......@@ -6385,46 +6409,72 @@ static void io_ring_file_put(struct io_ring_ctx *ctx, struct file *file)
}
struct io_file_put {
struct llist_node llist;
struct list_head list;
struct file *file;
};
static void io_ring_file_ref_flush(struct fixed_file_data *data)
static void io_file_put_work(struct work_struct *work)
{
struct fixed_file_ref_node *ref_node;
struct fixed_file_data *file_data;
struct io_ring_ctx *ctx;
struct io_file_put *pfile, *tmp;
struct llist_node *node;
unsigned long flags;
ref_node = container_of(work, struct fixed_file_ref_node, work);
file_data = ref_node->file_data;
ctx = file_data->ctx;
while ((node = llist_del_all(&data->put_llist)) != NULL) {
llist_for_each_entry_safe(pfile, tmp, node, llist) {
io_ring_file_put(data->ctx, pfile->file);
list_for_each_entry_safe(pfile, tmp, &ref_node->file_list, list) {
list_del_init(&pfile->list);
io_ring_file_put(ctx, pfile->file);
kfree(pfile);
}
}
spin_lock_irqsave(&file_data->lock, flags);
list_del_init(&ref_node->node);
spin_unlock_irqrestore(&file_data->lock, flags);
percpu_ref_exit(&ref_node->refs);
kfree(ref_node);
percpu_ref_put(&file_data->refs);
}
static void io_ring_file_ref_switch(struct work_struct *work)
static void io_file_data_ref_zero(struct percpu_ref *ref)
{
struct fixed_file_data *data;
struct fixed_file_ref_node *ref_node;
ref_node = container_of(ref, struct fixed_file_ref_node, refs);
data = container_of(work, struct fixed_file_data, ref_work);
io_ring_file_ref_flush(data);
percpu_ref_switch_to_percpu(&data->refs);
queue_work(system_wq, &ref_node->work);
}
static void io_file_data_ref_zero(struct percpu_ref *ref)
static struct fixed_file_ref_node *alloc_fixed_file_ref_node(
struct io_ring_ctx *ctx)
{
struct fixed_file_data *data;
struct fixed_file_ref_node *ref_node;
data = container_of(ref, struct fixed_file_data, refs);
ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
if (!ref_node)
return ERR_PTR(-ENOMEM);
/*
* We can't safely switch from inside this context, punt to wq. If
* the table ref is going away, the table is being unregistered.
* Don't queue up the async work for that case, the caller will
* handle it.
*/
if (!percpu_ref_is_dying(&data->refs))
queue_work(system_wq, &data->ref_work);
if (percpu_ref_init(&ref_node->refs, io_file_data_ref_zero,
0, GFP_KERNEL)) {
kfree(ref_node);
return ERR_PTR(-ENOMEM);
}
INIT_LIST_HEAD(&ref_node->node);
INIT_LIST_HEAD(&ref_node->file_list);
INIT_WORK(&ref_node->work, io_file_put_work);
ref_node->file_data = ctx->file_data;
return ref_node;
}
static void destroy_fixed_file_ref_node(struct fixed_file_ref_node *ref_node)
{
percpu_ref_exit(&ref_node->refs);
kfree(ref_node);
}
static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
......@@ -6435,6 +6485,8 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
struct file *file;
int fd, ret = 0;
unsigned i;
struct fixed_file_ref_node *ref_node;
unsigned long flags;
if (ctx->file_data)
return -EBUSY;
......@@ -6448,6 +6500,8 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
return -ENOMEM;
ctx->file_data->ctx = ctx;
init_completion(&ctx->file_data->done);
INIT_LIST_HEAD(&ctx->file_data->ref_list);
spin_lock_init(&ctx->file_data->lock);
nr_tables = DIV_ROUND_UP(nr_args, IORING_MAX_FILES_TABLE);
ctx->file_data->table = kcalloc(nr_tables,
......@@ -6459,15 +6513,13 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
return -ENOMEM;
}
if (percpu_ref_init(&ctx->file_data->refs, io_file_data_ref_zero,
if (percpu_ref_init(&ctx->file_data->refs, io_file_ref_kill,
PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) {
kfree(ctx->file_data->table);
kfree(ctx->file_data);
ctx->file_data = NULL;
return -ENOMEM;
}
ctx->file_data->put_llist.first = NULL;
INIT_WORK(&ctx->file_data->ref_work, io_ring_file_ref_switch);
if (io_sqe_alloc_file_tables(ctx, nr_tables, nr_args)) {
percpu_ref_exit(&ctx->file_data->refs);
......@@ -6530,9 +6582,22 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
}
ret = io_sqe_files_scm(ctx);
if (ret)
if (ret) {
io_sqe_files_unregister(ctx);
return ret;
}
ref_node = alloc_fixed_file_ref_node(ctx);
if (IS_ERR(ref_node)) {
io_sqe_files_unregister(ctx);
return PTR_ERR(ref_node);
}
ctx->file_data->cur_refs = &ref_node->refs;
spin_lock_irqsave(&ctx->file_data->lock, flags);
list_add(&ref_node->node, &ctx->file_data->ref_list);
spin_unlock_irqrestore(&ctx->file_data->lock, flags);
percpu_ref_get(&ctx->file_data->refs);
return ret;
}
......@@ -6579,30 +6644,21 @@ static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,
#endif
}
static void io_atomic_switch(struct percpu_ref *ref)
{
struct fixed_file_data *data;
/*
* Juggle reference to ensure we hit zero, if needed, so we can
* switch back to percpu mode
*/
data = container_of(ref, struct fixed_file_data, refs);
percpu_ref_put(&data->refs);
percpu_ref_get(&data->refs);
}
static int io_queue_file_removal(struct fixed_file_data *data,
struct file *file)
{
struct io_file_put *pfile;
struct percpu_ref *refs = data->cur_refs;
struct fixed_file_ref_node *ref_node;
pfile = kzalloc(sizeof(*pfile), GFP_KERNEL);
if (!pfile)
return -ENOMEM;
ref_node = container_of(refs, struct fixed_file_ref_node, refs);
pfile->file = file;
llist_add(&pfile->llist, &data->put_llist);
list_add(&pfile->list, &ref_node->file_list);
return 0;
}
......@@ -6611,17 +6667,23 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
unsigned nr_args)
{
struct fixed_file_data *data = ctx->file_data;
bool ref_switch = false;
struct fixed_file_ref_node *ref_node;
struct file *file;
__s32 __user *fds;
int fd, i, err;
__u32 done;
unsigned long flags;
bool needs_switch = false;
if (check_add_overflow(up->offset, nr_args, &done))
return -EOVERFLOW;
if (done > ctx->nr_user_files)
return -EINVAL;
ref_node = alloc_fixed_file_ref_node(ctx);
if (IS_ERR(ref_node))
return PTR_ERR(ref_node);
done = 0;
fds = u64_to_user_ptr(up->fds);
while (nr_args) {
......@@ -6642,7 +6704,7 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
if (err)
break;
table->files[index] = NULL;
ref_switch = true;
needs_switch = true;
}
if (fd != -1) {
file = fget(fd);
......@@ -6673,11 +6735,19 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
up->offset++;
}
if (ref_switch)
percpu_ref_switch_to_atomic(&data->refs, io_atomic_switch);
if (needs_switch) {
percpu_ref_kill(data->cur_refs);
spin_lock_irqsave(&data->lock, flags);
list_add(&ref_node->node, &data->ref_list);
data->cur_refs = &ref_node->refs;
spin_unlock_irqrestore(&data->lock, flags);
percpu_ref_get(&ctx->file_data->refs);
} else
destroy_fixed_file_ref_node(ref_node);
return done ? done : err;
}
static int io_sqe_files_update(struct io_ring_ctx *ctx, void __user *arg,
unsigned nr_args)
{
......@@ -7203,6 +7273,18 @@ static int io_remove_personalities(int id, void *p, void *data)
return 0;
}
static void io_ring_exit_work(struct work_struct *work)
{
struct io_ring_ctx *ctx;
ctx = container_of(work, struct io_ring_ctx, exit_work);
if (ctx->rings)
io_cqring_overflow_flush(ctx, true);
wait_for_completion(&ctx->completions[0]);
io_ring_ctx_free(ctx);
}
static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
{
mutex_lock(&ctx->uring_lock);
......@@ -7230,8 +7312,8 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
if (ctx->rings)
io_cqring_overflow_flush(ctx, true);
idr_for_each(&ctx->personality_idr, io_remove_personalities, ctx);
wait_for_completion(&ctx->completions[0]);
io_ring_ctx_free(ctx);
INIT_WORK(&ctx->exit_work, io_ring_exit_work);
queue_work(system_wq, &ctx->exit_work);
}
static int io_uring_release(struct inode *inode, struct file *file)
......
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