| // SPDX-License-Identifier: GPL-2.0 |
| #include <linux/kernel.h> |
| #include <linux/errno.h> |
| #include <linux/fs.h> |
| #include <linux/file.h> |
| #include <linux/blk-mq.h> |
| #include <linux/mm.h> |
| #include <linux/slab.h> |
| #include <linux/fsnotify.h> |
| #include <linux/poll.h> |
| #include <linux/nospec.h> |
| #include <linux/compat.h> |
| #include <linux/io_uring.h> |
| |
| #include <uapi/linux/io_uring.h> |
| |
| #include "io_uring.h" |
| #include "opdef.h" |
| #include "kbuf.h" |
| #include "rsrc.h" |
| #include "rw.h" |
| |
| struct io_rw { |
| /* NOTE: kiocb has the file as the first member, so don't do it here */ |
| struct kiocb kiocb; |
| u64 addr; |
| u32 len; |
| rwf_t flags; |
| }; |
| |
| static inline bool io_file_supports_nowait(struct io_kiocb *req) |
| { |
| return req->flags & REQ_F_SUPPORT_NOWAIT; |
| } |
| |
| int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe) |
| { |
| struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
| unsigned ioprio; |
| int ret; |
| |
| rw->kiocb.ki_pos = READ_ONCE(sqe->off); |
| /* used for fixed read/write too - just read unconditionally */ |
| req->buf_index = READ_ONCE(sqe->buf_index); |
| |
| if (req->opcode == IORING_OP_READ_FIXED || |
| req->opcode == IORING_OP_WRITE_FIXED) { |
| struct io_ring_ctx *ctx = req->ctx; |
| u16 index; |
| |
| if (unlikely(req->buf_index >= ctx->nr_user_bufs)) |
| return -EFAULT; |
| index = array_index_nospec(req->buf_index, ctx->nr_user_bufs); |
| req->imu = ctx->user_bufs[index]; |
| io_req_set_rsrc_node(req, ctx, 0); |
| } |
| |
| ioprio = READ_ONCE(sqe->ioprio); |
| if (ioprio) { |
| ret = ioprio_check_cap(ioprio); |
| if (ret) |
| return ret; |
| |
| rw->kiocb.ki_ioprio = ioprio; |
| } else { |
| rw->kiocb.ki_ioprio = get_current_ioprio(); |
| } |
| |
| rw->addr = READ_ONCE(sqe->addr); |
| rw->len = READ_ONCE(sqe->len); |
| rw->flags = READ_ONCE(sqe->rw_flags); |
| return 0; |
| } |
| |
| void io_readv_writev_cleanup(struct io_kiocb *req) |
| { |
| struct io_async_rw *io = req->async_data; |
| |
| kfree(io->free_iovec); |
| } |
| |
| static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) |
| { |
| switch (ret) { |
| case -EIOCBQUEUED: |
| break; |
| case -ERESTARTSYS: |
| case -ERESTARTNOINTR: |
| case -ERESTARTNOHAND: |
| case -ERESTART_RESTARTBLOCK: |
| /* |
| * We can't just restart the syscall, since previously |
| * submitted sqes may already be in progress. Just fail this |
| * IO with EINTR. |
| */ |
| ret = -EINTR; |
| fallthrough; |
| default: |
| kiocb->ki_complete(kiocb, ret); |
| } |
| } |
| |
| static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req) |
| { |
| struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
| |
| if (rw->kiocb.ki_pos != -1) |
| return &rw->kiocb.ki_pos; |
| |
| if (!(req->file->f_mode & FMODE_STREAM)) { |
| req->flags |= REQ_F_CUR_POS; |
| rw->kiocb.ki_pos = req->file->f_pos; |
| return &rw->kiocb.ki_pos; |
| } |
| |
| rw->kiocb.ki_pos = 0; |
| return NULL; |
| } |
| |
| static void io_req_task_queue_reissue(struct io_kiocb *req) |
| { |
| req->io_task_work.func = io_queue_iowq; |
| io_req_task_work_add(req); |
| } |
| |
| #ifdef CONFIG_BLOCK |
| static bool io_resubmit_prep(struct io_kiocb *req) |
| { |
| struct io_async_rw *io = req->async_data; |
| |
| if (!req_has_async_data(req)) |
| return !io_req_prep_async(req); |
| iov_iter_restore(&io->s.iter, &io->s.iter_state); |
| return true; |
| } |
| |
| static bool io_rw_should_reissue(struct io_kiocb *req) |
| { |
| umode_t mode = file_inode(req->file)->i_mode; |
| struct io_ring_ctx *ctx = req->ctx; |
| |
| if (!S_ISBLK(mode) && !S_ISREG(mode)) |
| return false; |
| if ((req->flags & REQ_F_NOWAIT) || (io_wq_current_is_worker() && |
| !(ctx->flags & IORING_SETUP_IOPOLL))) |
| return false; |
| /* |
| * If ref is dying, we might be running poll reap from the exit work. |
| * Don't attempt to reissue from that path, just let it fail with |
| * -EAGAIN. |
| */ |
| if (percpu_ref_is_dying(&ctx->refs)) |
| return false; |
| /* |
| * Play it safe and assume not safe to re-import and reissue if we're |
| * not in the original thread group (or in task context). |
| */ |
| if (!same_thread_group(req->task, current) || !in_task()) |
| return false; |
| return true; |
| } |
| #else |
| static bool io_resubmit_prep(struct io_kiocb *req) |
| { |
| return false; |
| } |
| static bool io_rw_should_reissue(struct io_kiocb *req) |
| { |
| return false; |
| } |
| #endif |
| |
| static void kiocb_end_write(struct io_kiocb *req) |
| { |
| /* |
| * Tell lockdep we inherited freeze protection from submission |
| * thread. |
| */ |
| if (req->flags & REQ_F_ISREG) { |
| struct super_block *sb = file_inode(req->file)->i_sb; |
| |
| __sb_writers_acquired(sb, SB_FREEZE_WRITE); |
| sb_end_write(sb); |
| } |
| } |
| |
| static bool __io_complete_rw_common(struct io_kiocb *req, long res) |
| { |
| struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
| |
| if (rw->kiocb.ki_flags & IOCB_WRITE) { |
| kiocb_end_write(req); |
| fsnotify_modify(req->file); |
| } else { |
| fsnotify_access(req->file); |
| } |
| if (unlikely(res != req->cqe.res)) { |
| if ((res == -EAGAIN || res == -EOPNOTSUPP) && |
| io_rw_should_reissue(req)) { |
| req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO; |
| return true; |
| } |
| req_set_fail(req); |
| req->cqe.res = res; |
| } |
| return false; |
| } |
| |
| static inline int io_fixup_rw_res(struct io_kiocb *req, long res) |
| { |
| struct io_async_rw *io = req->async_data; |
| |
| /* add previously done IO, if any */ |
| if (req_has_async_data(req) && io->bytes_done > 0) { |
| if (res < 0) |
| res = io->bytes_done; |
| else |
| res += io->bytes_done; |
| } |
| return res; |
| } |
| |
| static void io_complete_rw(struct kiocb *kiocb, long res) |
| { |
| struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb); |
| struct io_kiocb *req = cmd_to_io_kiocb(rw); |
| |
| if (__io_complete_rw_common(req, res)) |
| return; |
| io_req_set_res(req, io_fixup_rw_res(req, res), 0); |
| req->io_task_work.func = io_req_task_complete; |
| io_req_task_work_add(req); |
| } |
| |
| static void io_complete_rw_iopoll(struct kiocb *kiocb, long res) |
| { |
| struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb); |
| struct io_kiocb *req = cmd_to_io_kiocb(rw); |
| |
| if (kiocb->ki_flags & IOCB_WRITE) |
| kiocb_end_write(req); |
| if (unlikely(res != req->cqe.res)) { |
| if (res == -EAGAIN && io_rw_should_reissue(req)) { |
| req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO; |
| return; |
| } |
| req->cqe.res = res; |
| } |
| |
| /* order with io_iopoll_complete() checking ->iopoll_completed */ |
| smp_store_release(&req->iopoll_completed, 1); |
| } |
| |
| static int kiocb_done(struct io_kiocb *req, ssize_t ret, |
| unsigned int issue_flags) |
| { |
| struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
| unsigned final_ret = io_fixup_rw_res(req, ret); |
| |
| if (req->flags & REQ_F_CUR_POS) |
| req->file->f_pos = rw->kiocb.ki_pos; |
| if (ret >= 0 && (rw->kiocb.ki_complete == io_complete_rw)) { |
| if (!__io_complete_rw_common(req, ret)) { |
| io_req_set_res(req, final_ret, |
| io_put_kbuf(req, issue_flags)); |
| return IOU_OK; |
| } |
| } else { |
| io_rw_done(&rw->kiocb, ret); |
| } |
| |
| if (req->flags & REQ_F_REISSUE) { |
| req->flags &= ~REQ_F_REISSUE; |
| if (io_resubmit_prep(req)) |
| io_req_task_queue_reissue(req); |
| else |
| io_req_task_queue_fail(req, final_ret); |
| } |
| return IOU_ISSUE_SKIP_COMPLETE; |
| } |
| |
| #ifdef CONFIG_COMPAT |
| static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov, |
| unsigned int issue_flags) |
| { |
| struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
| struct compat_iovec __user *uiov; |
| compat_ssize_t clen; |
| void __user *buf; |
| size_t len; |
| |
| uiov = u64_to_user_ptr(rw->addr); |
| if (!access_ok(uiov, sizeof(*uiov))) |
| return -EFAULT; |
| if (__get_user(clen, &uiov->iov_len)) |
| return -EFAULT; |
| if (clen < 0) |
| return -EINVAL; |
| |
| len = clen; |
| buf = io_buffer_select(req, &len, issue_flags); |
| if (!buf) |
| return -ENOBUFS; |
| rw->addr = (unsigned long) buf; |
| iov[0].iov_base = buf; |
| rw->len = iov[0].iov_len = (compat_size_t) len; |
| return 0; |
| } |
| #endif |
| |
| static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov, |
| unsigned int issue_flags) |
| { |
| struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
| struct iovec __user *uiov = u64_to_user_ptr(rw->addr); |
| void __user *buf; |
| ssize_t len; |
| |
| if (copy_from_user(iov, uiov, sizeof(*uiov))) |
| return -EFAULT; |
| |
| len = iov[0].iov_len; |
| if (len < 0) |
| return -EINVAL; |
| buf = io_buffer_select(req, &len, issue_flags); |
| if (!buf) |
| return -ENOBUFS; |
| rw->addr = (unsigned long) buf; |
| iov[0].iov_base = buf; |
| rw->len = iov[0].iov_len = len; |
| return 0; |
| } |
| |
| static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov, |
| unsigned int issue_flags) |
| { |
| struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
| |
| if (req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)) { |
| iov[0].iov_base = u64_to_user_ptr(rw->addr); |
| iov[0].iov_len = rw->len; |
| return 0; |
| } |
| if (rw->len != 1) |
| return -EINVAL; |
| |
| #ifdef CONFIG_COMPAT |
| if (req->ctx->compat) |
| return io_compat_import(req, iov, issue_flags); |
| #endif |
| |
| return __io_iov_buffer_select(req, iov, issue_flags); |
| } |
| |
| static struct iovec *__io_import_iovec(int ddir, struct io_kiocb *req, |
| struct io_rw_state *s, |
| unsigned int issue_flags) |
| { |
| struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
| struct iov_iter *iter = &s->iter; |
| u8 opcode = req->opcode; |
| struct iovec *iovec; |
| void __user *buf; |
| size_t sqe_len; |
| ssize_t ret; |
| |
| if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) { |
| ret = io_import_fixed(ddir, iter, req->imu, rw->addr, rw->len); |
| if (ret) |
| return ERR_PTR(ret); |
| return NULL; |
| } |
| |
| buf = u64_to_user_ptr(rw->addr); |
| sqe_len = rw->len; |
| |
| if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) { |
| if (io_do_buffer_select(req)) { |
| buf = io_buffer_select(req, &sqe_len, issue_flags); |
| if (!buf) |
| return ERR_PTR(-ENOBUFS); |
| rw->addr = (unsigned long) buf; |
| rw->len = sqe_len; |
| } |
| |
| ret = import_single_range(ddir, buf, sqe_len, s->fast_iov, iter); |
| if (ret) |
| return ERR_PTR(ret); |
| return NULL; |
| } |
| |
| iovec = s->fast_iov; |
| if (req->flags & REQ_F_BUFFER_SELECT) { |
| ret = io_iov_buffer_select(req, iovec, issue_flags); |
| if (ret) |
| return ERR_PTR(ret); |
| iov_iter_init(iter, ddir, iovec, 1, iovec->iov_len); |
| return NULL; |
| } |
| |
| ret = __import_iovec(ddir, buf, sqe_len, UIO_FASTIOV, &iovec, iter, |
| req->ctx->compat); |
| if (unlikely(ret < 0)) |
| return ERR_PTR(ret); |
| return iovec; |
| } |
| |
| static inline int io_import_iovec(int rw, struct io_kiocb *req, |
| struct iovec **iovec, struct io_rw_state *s, |
| unsigned int issue_flags) |
| { |
| *iovec = __io_import_iovec(rw, req, s, issue_flags); |
| if (unlikely(IS_ERR(*iovec))) |
| return PTR_ERR(*iovec); |
| |
| iov_iter_save_state(&s->iter, &s->iter_state); |
| return 0; |
| } |
| |
| 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. |
| */ |
| static ssize_t loop_rw_iter(int ddir, struct io_rw *rw, struct iov_iter *iter) |
| { |
| struct kiocb *kiocb = &rw->kiocb; |
| struct file *file = kiocb->ki_filp; |
| ssize_t ret = 0; |
| loff_t *ppos; |
| |
| /* |
| * Don't support polled IO through this interface, and we can't |
| * support non-blocking either. For the latter, this just causes |
| * the kiocb to be handled from an async context. |
| */ |
| if (kiocb->ki_flags & IOCB_HIPRI) |
| return -EOPNOTSUPP; |
| if ((kiocb->ki_flags & IOCB_NOWAIT) && |
| !(kiocb->ki_filp->f_flags & O_NONBLOCK)) |
| return -EAGAIN; |
| |
| ppos = io_kiocb_ppos(kiocb); |
| |
| while (iov_iter_count(iter)) { |
| struct iovec iovec; |
| ssize_t nr; |
| |
| if (!iov_iter_is_bvec(iter)) { |
| iovec = iov_iter_iovec(iter); |
| } else { |
| iovec.iov_base = u64_to_user_ptr(rw->addr); |
| iovec.iov_len = rw->len; |
| } |
| |
| if (ddir == READ) { |
| nr = file->f_op->read(file, iovec.iov_base, |
| iovec.iov_len, ppos); |
| } else { |
| nr = file->f_op->write(file, iovec.iov_base, |
| iovec.iov_len, ppos); |
| } |
| |
| if (nr < 0) { |
| if (!ret) |
| ret = nr; |
| break; |
| } |
| ret += nr; |
| if (!iov_iter_is_bvec(iter)) { |
| iov_iter_advance(iter, nr); |
| } else { |
| rw->addr += nr; |
| rw->len -= nr; |
| if (!rw->len) |
| break; |
| } |
| if (nr != iovec.iov_len) |
| break; |
| } |
| |
| return ret; |
| } |
| |
| static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec, |
| const struct iovec *fast_iov, struct iov_iter *iter) |
| { |
| struct io_async_rw *io = req->async_data; |
| |
| memcpy(&io->s.iter, iter, sizeof(*iter)); |
| io->free_iovec = iovec; |
| io->bytes_done = 0; |
| /* can only be fixed buffers, no need to do anything */ |
| if (iov_iter_is_bvec(iter)) |
| return; |
| if (!iovec) { |
| unsigned iov_off = 0; |
| |
| io->s.iter.iov = io->s.fast_iov; |
| if (iter->iov != fast_iov) { |
| iov_off = iter->iov - fast_iov; |
| io->s.iter.iov += iov_off; |
| } |
| if (io->s.fast_iov != fast_iov) |
| memcpy(io->s.fast_iov + iov_off, fast_iov + iov_off, |
| sizeof(struct iovec) * iter->nr_segs); |
| } else { |
| req->flags |= REQ_F_NEED_CLEANUP; |
| } |
| } |
| |
| static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec, |
| struct io_rw_state *s, bool force) |
| { |
| if (!force && !io_op_defs[req->opcode].prep_async) |
| return 0; |
| if (!req_has_async_data(req)) { |
| struct io_async_rw *iorw; |
| |
| if (io_alloc_async_data(req)) { |
| kfree(iovec); |
| return -ENOMEM; |
| } |
| |
| io_req_map_rw(req, iovec, s->fast_iov, &s->iter); |
| iorw = req->async_data; |
| /* we've copied and mapped the iter, ensure state is saved */ |
| iov_iter_save_state(&iorw->s.iter, &iorw->s.iter_state); |
| } |
| return 0; |
| } |
| |
| static inline int io_rw_prep_async(struct io_kiocb *req, int rw) |
| { |
| struct io_async_rw *iorw = req->async_data; |
| struct iovec *iov; |
| int ret; |
| |
| /* submission path, ->uring_lock should already be taken */ |
| ret = io_import_iovec(rw, req, &iov, &iorw->s, 0); |
| if (unlikely(ret < 0)) |
| return ret; |
| |
| iorw->bytes_done = 0; |
| iorw->free_iovec = iov; |
| if (iov) |
| req->flags |= REQ_F_NEED_CLEANUP; |
| return 0; |
| } |
| |
| int io_readv_prep_async(struct io_kiocb *req) |
| { |
| return io_rw_prep_async(req, READ); |
| } |
| |
| int io_writev_prep_async(struct io_kiocb *req) |
| { |
| return io_rw_prep_async(req, WRITE); |
| } |
| |
| /* |
| * This is our waitqueue callback handler, registered through __folio_lock_async() |
| * when we initially tried to do the IO with the iocb armed our waitqueue. |
| * This gets called when the page is unlocked, and we generally expect that to |
| * happen when the page IO is completed and the page is now uptodate. This will |
| * queue a task_work based retry of the operation, attempting to copy the data |
| * again. If the latter fails because the page was NOT uptodate, then we will |
| * do a thread based blocking retry of the operation. That's the unexpected |
| * slow path. |
| */ |
| static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode, |
| int sync, void *arg) |
| { |
| struct wait_page_queue *wpq; |
| struct io_kiocb *req = wait->private; |
| struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
| struct wait_page_key *key = arg; |
| |
| wpq = container_of(wait, struct wait_page_queue, wait); |
| |
| if (!wake_page_match(wpq, key)) |
| return 0; |
| |
| rw->kiocb.ki_flags &= ~IOCB_WAITQ; |
| list_del_init(&wait->entry); |
| io_req_task_queue(req); |
| return 1; |
| } |
| |
| /* |
| * This controls whether a given IO request should be armed for async page |
| * based retry. If we return false here, the request is handed to the async |
| * worker threads for retry. If we're doing buffered reads on a regular file, |
| * we prepare a private wait_page_queue entry and retry the operation. This |
| * will either succeed because the page is now uptodate and unlocked, or it |
| * will register a callback when the page is unlocked at IO completion. Through |
| * that callback, io_uring uses task_work to setup a retry of the operation. |
| * That retry will attempt the buffered read again. The retry will generally |
| * succeed, or in rare cases where it fails, we then fall back to using the |
| * async worker threads for a blocking retry. |
| */ |
| static bool io_rw_should_retry(struct io_kiocb *req) |
| { |
| struct io_async_rw *io = req->async_data; |
| struct wait_page_queue *wait = &io->wpq; |
| struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
| struct kiocb *kiocb = &rw->kiocb; |
| |
| /* never retry for NOWAIT, we just complete with -EAGAIN */ |
| if (req->flags & REQ_F_NOWAIT) |
| return false; |
| |
| /* Only for buffered IO */ |
| if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI)) |
| return false; |
| |
| /* |
| * just use poll if we can, and don't attempt if the fs doesn't |
| * support callback based unlocks |
| */ |
| if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC)) |
| return false; |
| |
| wait->wait.func = io_async_buf_func; |
| wait->wait.private = req; |
| wait->wait.flags = 0; |
| INIT_LIST_HEAD(&wait->wait.entry); |
| kiocb->ki_flags |= IOCB_WAITQ; |
| kiocb->ki_flags &= ~IOCB_NOWAIT; |
| kiocb->ki_waitq = wait; |
| return true; |
| } |
| |
| static inline int io_iter_do_read(struct io_rw *rw, struct iov_iter *iter) |
| { |
| struct file *file = rw->kiocb.ki_filp; |
| |
| if (likely(file->f_op->read_iter)) |
| return call_read_iter(file, &rw->kiocb, iter); |
| else if (file->f_op->read) |
| return loop_rw_iter(READ, rw, iter); |
| else |
| return -EINVAL; |
| } |
| |
| static bool need_complete_io(struct io_kiocb *req) |
| { |
| return req->flags & REQ_F_ISREG || |
| S_ISBLK(file_inode(req->file)->i_mode); |
| } |
| |
| static int io_rw_init_file(struct io_kiocb *req, fmode_t mode) |
| { |
| struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
| struct kiocb *kiocb = &rw->kiocb; |
| struct io_ring_ctx *ctx = req->ctx; |
| struct file *file = req->file; |
| int ret; |
| |
| if (unlikely(!file || !(file->f_mode & mode))) |
| return -EBADF; |
| |
| if (!io_req_ffs_set(req)) |
| req->flags |= io_file_get_flags(file) << REQ_F_SUPPORT_NOWAIT_BIT; |
| |
| kiocb->ki_flags = file->f_iocb_flags; |
| ret = kiocb_set_rw_flags(kiocb, rw->flags); |
| if (unlikely(ret)) |
| return ret; |
| |
| /* |
| * If the file is marked O_NONBLOCK, still allow retry for it if it |
| * supports async. Otherwise it's impossible to use O_NONBLOCK files |
| * reliably. If not, or it IOCB_NOWAIT is set, don't retry. |
| */ |
| if ((kiocb->ki_flags & IOCB_NOWAIT) || |
| ((file->f_flags & O_NONBLOCK) && !io_file_supports_nowait(req))) |
| req->flags |= REQ_F_NOWAIT; |
| |
| if (ctx->flags & IORING_SETUP_IOPOLL) { |
| if (!(kiocb->ki_flags & IOCB_DIRECT) || !file->f_op->iopoll) |
| return -EOPNOTSUPP; |
| |
| kiocb->private = NULL; |
| kiocb->ki_flags |= IOCB_HIPRI | IOCB_ALLOC_CACHE; |
| kiocb->ki_complete = io_complete_rw_iopoll; |
| req->iopoll_completed = 0; |
| } else { |
| if (kiocb->ki_flags & IOCB_HIPRI) |
| return -EINVAL; |
| kiocb->ki_complete = io_complete_rw; |
| } |
| |
| return 0; |
| } |
| |
| int io_read(struct io_kiocb *req, unsigned int issue_flags) |
| { |
| struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
| struct io_rw_state __s, *s = &__s; |
| struct iovec *iovec; |
| struct kiocb *kiocb = &rw->kiocb; |
| bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; |
| struct io_async_rw *io; |
| ssize_t ret, ret2; |
| loff_t *ppos; |
| |
| if (!req_has_async_data(req)) { |
| ret = io_import_iovec(READ, req, &iovec, s, issue_flags); |
| if (unlikely(ret < 0)) |
| return ret; |
| } else { |
| io = req->async_data; |
| s = &io->s; |
| |
| /* |
| * Safe and required to re-import if we're using provided |
| * buffers, as we dropped the selected one before retry. |
| */ |
| if (io_do_buffer_select(req)) { |
| ret = io_import_iovec(READ, req, &iovec, s, issue_flags); |
| if (unlikely(ret < 0)) |
| return ret; |
| } |
| |
| /* |
| * We come here from an earlier attempt, restore our state to |
| * match in case it doesn't. It's cheap enough that we don't |
| * need to make this conditional. |
| */ |
| iov_iter_restore(&s->iter, &s->iter_state); |
| iovec = NULL; |
| } |
| ret = io_rw_init_file(req, FMODE_READ); |
| if (unlikely(ret)) { |
| kfree(iovec); |
| return ret; |
| } |
| req->cqe.res = iov_iter_count(&s->iter); |
| |
| if (force_nonblock) { |
| /* If the file doesn't support async, just async punt */ |
| if (unlikely(!io_file_supports_nowait(req))) { |
| ret = io_setup_async_rw(req, iovec, s, true); |
| return ret ?: -EAGAIN; |
| } |
| kiocb->ki_flags |= IOCB_NOWAIT; |
| } else { |
| /* Ensure we clear previously set non-block flag */ |
| kiocb->ki_flags &= ~IOCB_NOWAIT; |
| } |
| |
| ppos = io_kiocb_update_pos(req); |
| |
| ret = rw_verify_area(READ, req->file, ppos, req->cqe.res); |
| if (unlikely(ret)) { |
| kfree(iovec); |
| return ret; |
| } |
| |
| ret = io_iter_do_read(rw, &s->iter); |
| |
| if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) { |
| req->flags &= ~REQ_F_REISSUE; |
| /* if we can poll, just do that */ |
| if (req->opcode == IORING_OP_READ && file_can_poll(req->file)) |
| return -EAGAIN; |
| /* IOPOLL retry should happen for io-wq threads */ |
| if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL)) |
| goto done; |
| /* no retry on NONBLOCK nor RWF_NOWAIT */ |
| if (req->flags & REQ_F_NOWAIT) |
| goto done; |
| ret = 0; |
| } else if (ret == -EIOCBQUEUED) { |
| if (iovec) |
| kfree(iovec); |
| return IOU_ISSUE_SKIP_COMPLETE; |
| } else if (ret == req->cqe.res || ret <= 0 || !force_nonblock || |
| (req->flags & REQ_F_NOWAIT) || !need_complete_io(req)) { |
| /* read all, failed, already did sync or don't want to retry */ |
| goto done; |
| } |
| |
| /* |
| * Don't depend on the iter state matching what was consumed, or being |
| * untouched in case of error. Restore it and we'll advance it |
| * manually if we need to. |
| */ |
| iov_iter_restore(&s->iter, &s->iter_state); |
| |
| ret2 = io_setup_async_rw(req, iovec, s, true); |
| if (ret2) |
| return ret2; |
| |
| iovec = NULL; |
| io = req->async_data; |
| s = &io->s; |
| /* |
| * Now use our persistent iterator and state, if we aren't already. |
| * We've restored and mapped the iter to match. |
| */ |
| |
| do { |
| /* |
| * We end up here because of a partial read, either from |
| * above or inside this loop. Advance the iter by the bytes |
| * that were consumed. |
| */ |
| iov_iter_advance(&s->iter, ret); |
| if (!iov_iter_count(&s->iter)) |
| break; |
| io->bytes_done += ret; |
| iov_iter_save_state(&s->iter, &s->iter_state); |
| |
| /* if we can retry, do so with the callbacks armed */ |
| if (!io_rw_should_retry(req)) { |
| kiocb->ki_flags &= ~IOCB_WAITQ; |
| return -EAGAIN; |
| } |
| |
| /* |
| * Now retry read with the IOCB_WAITQ parts set in the iocb. If |
| * we get -EIOCBQUEUED, then we'll get a notification when the |
| * desired page gets unlocked. We can also get a partial read |
| * here, and if we do, then just retry at the new offset. |
| */ |
| ret = io_iter_do_read(rw, &s->iter); |
| if (ret == -EIOCBQUEUED) |
| return IOU_ISSUE_SKIP_COMPLETE; |
| /* we got some bytes, but not all. retry. */ |
| kiocb->ki_flags &= ~IOCB_WAITQ; |
| iov_iter_restore(&s->iter, &s->iter_state); |
| } while (ret > 0); |
| done: |
| /* it's faster to check here then delegate to kfree */ |
| if (iovec) |
| kfree(iovec); |
| return kiocb_done(req, ret, issue_flags); |
| } |
| |
| int io_write(struct io_kiocb *req, unsigned int issue_flags) |
| { |
| struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
| struct io_rw_state __s, *s = &__s; |
| struct iovec *iovec; |
| struct kiocb *kiocb = &rw->kiocb; |
| bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; |
| ssize_t ret, ret2; |
| loff_t *ppos; |
| |
| if (!req_has_async_data(req)) { |
| ret = io_import_iovec(WRITE, req, &iovec, s, issue_flags); |
| if (unlikely(ret < 0)) |
| return ret; |
| } else { |
| struct io_async_rw *io = req->async_data; |
| |
| s = &io->s; |
| iov_iter_restore(&s->iter, &s->iter_state); |
| iovec = NULL; |
| } |
| ret = io_rw_init_file(req, FMODE_WRITE); |
| if (unlikely(ret)) { |
| kfree(iovec); |
| return ret; |
| } |
| req->cqe.res = iov_iter_count(&s->iter); |
| |
| if (force_nonblock) { |
| /* If the file doesn't support async, just async punt */ |
| if (unlikely(!io_file_supports_nowait(req))) |
| goto copy_iov; |
| |
| /* File path supports NOWAIT for non-direct_IO only for block devices. */ |
| if (!(kiocb->ki_flags & IOCB_DIRECT) && |
| !(kiocb->ki_filp->f_mode & FMODE_BUF_WASYNC) && |
| (req->flags & REQ_F_ISREG)) |
| goto copy_iov; |
| |
| kiocb->ki_flags |= IOCB_NOWAIT; |
| } else { |
| /* Ensure we clear previously set non-block flag */ |
| kiocb->ki_flags &= ~IOCB_NOWAIT; |
| } |
| |
| ppos = io_kiocb_update_pos(req); |
| |
| ret = rw_verify_area(WRITE, req->file, ppos, req->cqe.res); |
| if (unlikely(ret)) { |
| kfree(iovec); |
| return ret; |
| } |
| |
| /* |
| * Open-code file_start_write here to grab freeze protection, |
| * which will be released by another thread in |
| * io_complete_rw(). Fool lockdep by telling it the lock got |
| * released so that it doesn't complain about the held lock when |
| * we return to userspace. |
| */ |
| if (req->flags & REQ_F_ISREG) { |
| sb_start_write(file_inode(req->file)->i_sb); |
| __sb_writers_release(file_inode(req->file)->i_sb, |
| SB_FREEZE_WRITE); |
| } |
| kiocb->ki_flags |= IOCB_WRITE; |
| |
| if (likely(req->file->f_op->write_iter)) |
| ret2 = call_write_iter(req->file, kiocb, &s->iter); |
| else if (req->file->f_op->write) |
| ret2 = loop_rw_iter(WRITE, rw, &s->iter); |
| else |
| ret2 = -EINVAL; |
| |
| if (req->flags & REQ_F_REISSUE) { |
| req->flags &= ~REQ_F_REISSUE; |
| ret2 = -EAGAIN; |
| } |
| |
| /* |
| * Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just |
| * retry them without IOCB_NOWAIT. |
| */ |
| if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT)) |
| ret2 = -EAGAIN; |
| /* no retry on NONBLOCK nor RWF_NOWAIT */ |
| if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT)) |
| goto done; |
| if (!force_nonblock || ret2 != -EAGAIN) { |
| /* IOPOLL retry should happen for io-wq threads */ |
| if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL)) |
| goto copy_iov; |
| |
| if (ret2 != req->cqe.res && ret2 >= 0 && need_complete_io(req)) { |
| struct io_async_rw *rw; |
| |
| trace_io_uring_short_write(req->ctx, kiocb->ki_pos - ret2, |
| req->cqe.res, ret2); |
| |
| /* This is a partial write. The file pos has already been |
| * updated, setup the async struct to complete the request |
| * in the worker. Also update bytes_done to account for |
| * the bytes already written. |
| */ |
| iov_iter_save_state(&s->iter, &s->iter_state); |
| ret = io_setup_async_rw(req, iovec, s, true); |
| |
| rw = req->async_data; |
| if (rw) |
| rw->bytes_done += ret2; |
| |
| if (kiocb->ki_flags & IOCB_WRITE) |
| kiocb_end_write(req); |
| return ret ? ret : -EAGAIN; |
| } |
| done: |
| ret = kiocb_done(req, ret2, issue_flags); |
| } else { |
| copy_iov: |
| iov_iter_restore(&s->iter, &s->iter_state); |
| ret = io_setup_async_rw(req, iovec, s, false); |
| if (!ret) { |
| if (kiocb->ki_flags & IOCB_WRITE) |
| kiocb_end_write(req); |
| return -EAGAIN; |
| } |
| return ret; |
| } |
| /* it's reportedly faster than delegating the null check to kfree() */ |
| if (iovec) |
| kfree(iovec); |
| return ret; |
| } |
| |
| static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx) |
| { |
| io_commit_cqring_flush(ctx); |
| if (ctx->flags & IORING_SETUP_SQPOLL) |
| io_cqring_wake(ctx); |
| } |
| |
| int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin) |
| { |
| struct io_wq_work_node *pos, *start, *prev; |
| unsigned int poll_flags = BLK_POLL_NOSLEEP; |
| DEFINE_IO_COMP_BATCH(iob); |
| int nr_events = 0; |
| |
| /* |
| * Only spin for completions if we don't have multiple devices hanging |
| * off our complete list. |
| */ |
| if (ctx->poll_multi_queue || force_nonspin) |
| poll_flags |= BLK_POLL_ONESHOT; |
| |
| wq_list_for_each(pos, start, &ctx->iopoll_list) { |
| struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list); |
| struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
| int ret; |
| |
| /* |
| * 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 (READ_ONCE(req->iopoll_completed)) |
| break; |
| |
| ret = rw->kiocb.ki_filp->f_op->iopoll(&rw->kiocb, &iob, poll_flags); |
| if (unlikely(ret < 0)) |
| return ret; |
| else if (ret) |
| poll_flags |= BLK_POLL_ONESHOT; |
| |
| /* iopoll may have completed current req */ |
| if (!rq_list_empty(iob.req_list) || |
| READ_ONCE(req->iopoll_completed)) |
| break; |
| } |
| |
| if (!rq_list_empty(iob.req_list)) |
| iob.complete(&iob); |
| else if (!pos) |
| return 0; |
| |
| prev = start; |
| wq_list_for_each_resume(pos, prev) { |
| struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list); |
| |
| /* order with io_complete_rw_iopoll(), e.g. ->result updates */ |
| if (!smp_load_acquire(&req->iopoll_completed)) |
| break; |
| nr_events++; |
| if (unlikely(req->flags & REQ_F_CQE_SKIP)) |
| continue; |
| |
| req->cqe.flags = io_put_kbuf(req, 0); |
| __io_fill_cqe_req(req->ctx, req); |
| } |
| |
| if (unlikely(!nr_events)) |
| return 0; |
| |
| io_commit_cqring(ctx); |
| io_cqring_ev_posted_iopoll(ctx); |
| pos = start ? start->next : ctx->iopoll_list.first; |
| wq_list_cut(&ctx->iopoll_list, prev, start); |
| io_free_batch_list(ctx, pos); |
| return nr_events; |
| } |