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author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-29 01:23:16 +0200 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-29 01:23:16 +0200 |
commit | 24148d8648e37f8c15bedddfa50d14a31a0582c5 (patch) | |
tree | 94195f7e9efaf0ee3d0b50845b059db67972ef59 /fs/io_uring.c | |
parent | Merge tag 'devprop-5.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/... (diff) | |
parent | io_uring: don't bounce block based -EAGAIN retry off task_work (diff) | |
download | linux-24148d8648e37f8c15bedddfa50d14a31a0582c5.tar.xz linux-24148d8648e37f8c15bedddfa50d14a31a0582c5.zip |
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
Diffstat (limited to 'fs/io_uring.c')
-rw-r--r-- | fs/io_uring.c | 99 |
1 files changed, 57 insertions, 42 deletions
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 |