// SPDX-License-Identifier: GPL-2.0#include <linux/kernel.h>#include <linux/errno.h>#include <linux/fs.h>#include <linux/file.h>#include <linux/mm.h>#include <linux/slab.h>#include <linux/namei.h>#include <linux/poll.h>#include <linux/vmalloc.h>#include <linux/io_uring.h> #include <uapi/linux/io_uring.h> #include "io_uring.h"#include "opdef.h"#include "kbuf.h"#include "memmap.h" /* BIDs are addressed by a 16-bit field in a CQE */#define MAX_BIDS_PER_BGID (1 << 16) struct kmem_cache *io_buf_cachep; struct io_provide_buf { struct file *file; __u64 addr; __u32 len; __u32 bgid; __u32 nbufs; __u16 bid;}; static inline struct io_buffer_list *io_buffer_get_list(struct io_ring_ctx *ctx, unsigned int bgid){ lockdep_assert_held(&ctx->uring_lock); return xa_load(&ctx->io_bl_xa, bgid);} static int io_buffer_add_list(struct io_ring_ctx *ctx, struct io_buffer_list *bl, unsigned int bgid){ /* * Store buffer group ID and finally mark the list as visible. * The normal lookup doesn't care about the visibility as we're * always under the ->uring_lock, but the RCU lookup from mmap does. */ bl->bgid = bgid; atomic_set(&bl->refs, 1); return xa_err(xa_store(&ctx->io_bl_xa, bgid, bl, GFP_KERNEL));} bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags){ struct io_ring_ctx *ctx = req->ctx; struct io_buffer_list *bl; struct io_buffer *buf; io_ring_submit_lock(ctx, issue_flags); buf = req->kbuf; bl = io_buffer_get_list(ctx, buf->bgid); list_add(&buf->list, &bl->buf_list); req->flags &= ~REQ_F_BUFFER_SELECTED; req->buf_index = buf->bgid; io_ring_submit_unlock(ctx, issue_flags); return true;} void __io_put_kbuf(struct io_kiocb *req, int len, unsigned issue_flags){ /* * We can add this buffer back to two lists: * * 1) The io_buffers_cache list. This one is protected by the * ctx->uring_lock. If we already hold this lock, add back to this * list as we can grab it from issue as well. * 2) The io_buffers_comp list. This one is protected by the * ctx->completion_lock. * * We migrate buffers from the comp_list to the issue cache list * when we need one. */ if (issue_flags & IO_URING_F_UNLOCKED) { struct io_ring_ctx *ctx = req->ctx; spin_lock(&ctx->completion_lock); __io_put_kbuf_list(req, len, &ctx->io_buffers_comp); spin_unlock(&ctx->completion_lock); } else { lockdep_assert_held(&req->ctx->uring_lock); __io_put_kbuf_list(req, len, &req->ctx->io_buffers_cache); }} static void __user *io_provided_buffer_select(struct io_kiocb *req, size_t *len, struct io_buffer_list *bl){ if (!list_empty(&bl->buf_list)) { struct io_buffer *kbuf; kbuf = list_first_entry(&bl->buf_list, struct io_buffer, list); list_del(&kbuf->list); if (*len == 0 || *len > kbuf->len) *len = kbuf->len; if (list_empty(&bl->buf_list)) req->flags |= REQ_F_BL_EMPTY; req->flags |= REQ_F_BUFFER_SELECTED; req->kbuf = kbuf; req->buf_index = kbuf->bid; return u64_to_user_ptr(kbuf->addr); } return NULL;} static int io_provided_buffers_select(struct io_kiocb *req, size_t *len, struct io_buffer_list *bl, struct iovec *iov){ void __user *buf; buf = io_provided_buffer_select(req, len, bl); if (unlikely(!buf)) return -ENOBUFS; iov[0].iov_base = buf; iov[0].iov_len = *len; return 1;} static void __user *io_ring_buffer_select(struct io_kiocb *req, size_t *len, struct io_buffer_list *bl, unsigned int issue_flags){ struct io_uring_buf_ring *br = bl->buf_ring; __u16 tail, head = bl->head; struct io_uring_buf *buf; void __user *ret; tail = smp_load_acquire(&br->tail); if (unlikely(tail == head)) return NULL; if (head + 1 == tail) req->flags |= REQ_F_BL_EMPTY; buf = io_ring_head_to_buf(br, head, bl->mask); if (*len == 0 || *len > buf->len) *len = buf->len; req->flags |= REQ_F_BUFFER_RING | REQ_F_BUFFERS_COMMIT; req->buf_list = bl; req->buf_index = buf->bid; ret = u64_to_user_ptr(buf->addr); if (issue_flags & IO_URING_F_UNLOCKED || !io_file_can_poll(req)) { /* * If we came in unlocked, we have no choice but to consume the * buffer here, otherwise nothing ensures that the buffer won't * get used by others. This does mean it'll be pinned until the * IO completes, coming in unlocked means we're being called from * io-wq context and there may be further retries in async hybrid * mode. For the locked case, the caller must call commit when * the transfer completes (or if we get -EAGAIN and must poll of * retry). */ io_kbuf_commit(req, bl, *len, 1); req->buf_list = NULL; } return ret;} void __user *io_buffer_select(struct io_kiocb *req, size_t *len, unsigned int issue_flags){ struct io_ring_ctx *ctx = req->ctx; struct io_buffer_list *bl; void __user *ret = NULL; io_ring_submit_lock(req->ctx, issue_flags); bl = io_buffer_get_list(ctx, req->buf_index); if (likely(bl)) { if (bl->flags & IOBL_BUF_RING) ret = io_ring_buffer_select(req, len, bl, issue_flags); else ret = io_provided_buffer_select(req, len, bl); } io_ring_submit_unlock(req->ctx, issue_flags); return ret;} /* cap it at a reasonable 256, will be one page even for 4K */#define PEEK_MAX_IMPORT 256 static int io_ring_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg, struct io_buffer_list *bl){ struct io_uring_buf_ring *br = bl->buf_ring; struct iovec *iov = arg->iovs; int nr_iovs = arg->nr_iovs; __u16 nr_avail, tail, head; struct io_uring_buf *buf; tail = smp_load_acquire(&br->tail); head = bl->head; nr_avail = min_t(__u16, tail - head, UIO_MAXIOV); if (unlikely(!nr_avail)) return -ENOBUFS; buf = io_ring_head_to_buf(br, head, bl->mask); if (arg->max_len) { u32 len = READ_ONCE(buf->len); if (unlikely(!len)) return -ENOBUFS; /* * Limit incremental buffers to 1 segment. No point trying * to peek ahead and map more than we need, when the buffers * themselves should be large when setup with * IOU_PBUF_RING_INC. */ if (bl->flags & IOBL_INC) { nr_avail = 1; } else { size_t needed; needed = (arg->max_len + len - 1) / len; needed = min_not_zero(needed, (size_t) PEEK_MAX_IMPORT); if (nr_avail > needed) nr_avail = needed; } } /* * only alloc a bigger array if we know we have data to map, eg not * a speculative peek operation. */ if (arg->mode & KBUF_MODE_EXPAND && nr_avail > nr_iovs && arg->max_len) { iov = kmalloc_array(nr_avail, sizeof(struct iovec), GFP_KERNEL); if (unlikely(!iov)) return -ENOMEM; if (arg->mode & KBUF_MODE_FREE) kfree(arg->iovs); arg->iovs = iov; nr_iovs = nr_avail; } else if (nr_avail < nr_iovs) { nr_iovs = nr_avail; } /* set it to max, if not set, so we can use it unconditionally */ if (!arg->max_len) arg->max_len = INT_MAX; req->buf_index = buf->bid; do { u32 len = buf->len; /* truncate end piece, if needed, for non partial buffers */ if (len > arg->max_len) { len = arg->max_len; if (!(bl->flags & IOBL_INC)) buf->len = len; } iov->iov_base = u64_to_user_ptr(buf->addr); iov->iov_len = len; iov++; arg->out_len += len; arg->max_len -= len; if (!arg->max_len) break; buf = io_ring_head_to_buf(br, ++head, bl->mask); } while (--nr_iovs); if (head == tail) req->flags |= REQ_F_BL_EMPTY; req->flags |= REQ_F_BUFFER_RING; req->buf_list = bl; return iov - arg->iovs;} int io_buffers_select(struct io_kiocb *req, struct buf_sel_arg *arg, unsigned int issue_flags){ struct io_ring_ctx *ctx = req->ctx; struct io_buffer_list *bl; int ret = -ENOENT; io_ring_submit_lock(ctx, issue_flags); bl = io_buffer_get_list(ctx, req->buf_index); if (unlikely(!bl)) goto out_unlock; if (bl->flags & IOBL_BUF_RING) { ret = io_ring_buffers_peek(req, arg, bl); /* * Don't recycle these buffers if we need to go through poll. * Nobody else can use them anyway, and holding on to provided * buffers for a send/write operation would happen on the app * side anyway with normal buffers. Besides, we already * committed them, they cannot be put back in the queue. */ if (ret > 0) { req->flags |= REQ_F_BUFFERS_COMMIT | REQ_F_BL_NO_RECYCLE; io_kbuf_commit(req, bl, arg->out_len, ret); } } else { ret = io_provided_buffers_select(req, &arg->out_len, bl, arg->iovs); }out_unlock: io_ring_submit_unlock(ctx, issue_flags); return ret;} int io_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg){ struct io_ring_ctx *ctx = req->ctx; struct io_buffer_list *bl; int ret; lockdep_assert_held(&ctx->uring_lock); bl = io_buffer_get_list(ctx, req->buf_index); if (unlikely(!bl)) return -ENOENT; if (bl->flags & IOBL_BUF_RING) { ret = io_ring_buffers_peek(req, arg, bl); if (ret > 0) req->flags |= REQ_F_BUFFERS_COMMIT; return ret; } /* don't support multiple buffer selections for legacy */ return io_provided_buffers_select(req, &arg->max_len, bl, arg->iovs);} static int __io_remove_buffers(struct io_ring_ctx *ctx, struct io_buffer_list *bl, unsigned nbufs){ unsigned i = 0; /* shouldn't happen */ if (!nbufs) return 0; if (bl->flags & IOBL_BUF_RING) { i = bl->buf_ring->tail - bl->head; if (bl->buf_nr_pages) { int j; if (!(bl->flags & IOBL_MMAP)) { for (j = 0; j < bl->buf_nr_pages; j++) unpin_user_page(bl->buf_pages[j]); } io_pages_unmap(bl->buf_ring, &bl->buf_pages, &bl->buf_nr_pages, bl->flags & IOBL_MMAP); bl->flags &= ~IOBL_MMAP; } /* make sure it's seen as empty */ INIT_LIST_HEAD(&bl->buf_list); bl->flags &= ~IOBL_BUF_RING; return i; } /* protects io_buffers_cache */ lockdep_assert_held(&ctx->uring_lock); while (!list_empty(&bl->buf_list)) { struct io_buffer *nxt; nxt = list_first_entry(&bl->buf_list, struct io_buffer, list); list_move(&nxt->list, &ctx->io_buffers_cache); if (++i == nbufs) return i; cond_resched(); } return i;} void io_put_bl(struct io_ring_ctx *ctx, struct io_buffer_list *bl){ if (atomic_dec_and_test(&bl->refs)) { __io_remove_buffers(ctx, bl, -1U); kfree_rcu(bl, rcu); }} void io_destroy_buffers(struct io_ring_ctx *ctx){ struct io_buffer_list *bl; struct list_head *item, *tmp; struct io_buffer *buf; unsigned long index; xa_for_each(&ctx->io_bl_xa, index, bl) { xa_erase(&ctx->io_bl_xa, bl->bgid); io_put_bl(ctx, bl); } /* * Move deferred locked entries to cache before pruning */ spin_lock(&ctx->completion_lock); if (!list_empty(&ctx->io_buffers_comp)) list_splice_init(&ctx->io_buffers_comp, &ctx->io_buffers_cache); spin_unlock(&ctx->completion_lock); list_for_each_safe(item, tmp, &ctx->io_buffers_cache) { buf = list_entry(item, struct io_buffer, list); kmem_cache_free(io_buf_cachep, buf); }} int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe){ struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf); u64 tmp; if (sqe->rw_flags || sqe->addr || sqe->len || sqe->off || sqe->splice_fd_in) return -EINVAL; tmp = READ_ONCE(sqe->fd); if (!tmp || tmp > MAX_BIDS_PER_BGID) return -EINVAL; memset(p, 0, sizeof(*p)); p->nbufs = tmp; p->bgid = READ_ONCE(sqe->buf_group); return 0;} int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags){ struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf); struct io_ring_ctx *ctx = req->ctx; struct io_buffer_list *bl; int ret = 0; io_ring_submit_lock(ctx, issue_flags); ret = -ENOENT; bl = io_buffer_get_list(ctx, p->bgid); if (bl) { ret = -EINVAL; /* can't use provide/remove buffers command on mapped buffers */ if (!(bl->flags & IOBL_BUF_RING)) ret = __io_remove_buffers(ctx, bl, p->nbufs); } io_ring_submit_unlock(ctx, issue_flags); if (ret < 0) req_set_fail(req); io_req_set_res(req, ret, 0); return IOU_OK;} int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe){ unsigned long size, tmp_check; struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf); u64 tmp; if (sqe->rw_flags || sqe->splice_fd_in) return -EINVAL; tmp = READ_ONCE(sqe->fd); if (!tmp || tmp > MAX_BIDS_PER_BGID) return -E2BIG; p->nbufs = tmp; p->addr = READ_ONCE(sqe->addr); p->len = READ_ONCE(sqe->len); if (check_mul_overflow((unsigned long)p->len, (unsigned long)p->nbufs, &size)) return -EOVERFLOW; if (check_add_overflow((unsigned long)p->addr, size, &tmp_check)) return -EOVERFLOW; size = (unsigned long)p->len * p->nbufs; if (!access_ok(u64_to_user_ptr(p->addr), size)) return -EFAULT; p->bgid = READ_ONCE(sqe->buf_group); tmp = READ_ONCE(sqe->off); if (tmp > USHRT_MAX) return -E2BIG; if (tmp + p->nbufs > MAX_BIDS_PER_BGID) return -EINVAL; p->bid = tmp; return 0;}Lines 1–500 of 842. 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// SPDX-License-Identifier: GPL-2.0 #include <linux/kernel.h> #include <linux/errno.h> #include <linux/fs.h> #include <linux/file.h> #include <linux/mm.h> #include <linux/slab.h> #include <linux/namei.h> #include <linux/poll.h> #include <linux/vmalloc.h> #include <linux/io_uring.h> #include <uapi/linux/io_uring.h> #include "io_uring.h" #include "opdef.h" #include "kbuf.h" #include "memmap.h" /* BIDs are addressed by a 16-bit field in a CQE */ #define MAX_BIDS_PER_BGID (1 << 16) struct kmem_cache *io_buf_cachep; struct io_provide_buf { struct file *file; __u64 addr; __u32 len; __u32 bgid; __u32 nbufs; __u16 bid; }; static inline struct io_buffer_list *io_buffer_get_list(struct io_ring_ctx *ctx, unsigned int bgid) { lockdep_assert_held(&ctx->uring_lock); return xa_load(&ctx->io_bl_xa, bgid); } static int io_buffer_add_list(struct io_ring_ctx *ctx, struct io_buffer_list *bl, unsigned int bgid) { /* * Store buffer group ID and finally mark the list as visible. * The normal lookup doesn't care about the visibility as we're * always under the ->uring_lock, but the RCU lookup from mmap does. */ bl->bgid = bgid; atomic_set(&bl->refs, 1); return xa_err(xa_store(&ctx->io_bl_xa, bgid, bl, GFP_KERNEL)); } bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags) { struct io_ring_ctx *ctx = req->ctx; struct io_buffer_list *bl; struct io_buffer *buf; io_ring_submit_lock(ctx, issue_flags); buf = req->kbuf; bl = io_buffer_get_list(ctx, buf->bgid); list_add(&buf->list, &bl->buf_list); req->flags &= ~REQ_F_BUFFER_SELECTED; req->buf_index = buf->bgid; io_ring_submit_unlock(ctx, issue_flags); return true; } void __io_put_kbuf(struct io_kiocb *req, int len, unsigned issue_flags) { /* * We can add this buffer back to two lists: * * 1) The io_buffers_cache list. This one is protected by the * ctx->uring_lock. If we already hold this lock, add back to this * list as we can grab it from issue as well. * 2) The io_buffers_comp list. This one is protected by the * ctx->completion_lock. * * We migrate buffers from the comp_list to the issue cache list * when we need one. */ if (issue_flags & IO_URING_F_UNLOCKED) { struct io_ring_ctx *ctx = req->ctx; spin_lock(&ctx->completion_lock); __io_put_kbuf_list(req, len, &ctx->io_buffers_comp); spin_unlock(&ctx->completion_lock); } else { lockdep_assert_held(&req->ctx->uring_lock); __io_put_kbuf_list(req, len, &req->ctx->io_buffers_cache); } } static void __user *io_provided_buffer_select(struct io_kiocb *req, size_t *len, struct io_buffer_list *bl) { if (!list_empty(&bl->buf_list)) { struct io_buffer *kbuf; kbuf = list_first_entry(&bl->buf_list, struct io_buffer, list); list_del(&kbuf->list); if (*len == 0 || *len > kbuf->len) *len = kbuf->len; if (list_empty(&bl->buf_list)) req->flags |= REQ_F_BL_EMPTY; req->flags |= REQ_F_BUFFER_SELECTED; req->kbuf = kbuf; req->buf_index = kbuf->bid; return u64_to_user_ptr(kbuf->addr); } return NULL; } static int io_provided_buffers_select(struct io_kiocb *req, size_t *len, struct io_buffer_list *bl, struct iovec *iov) { void __user *buf; buf = io_provided_buffer_select(req, len, bl); if (unlikely(!buf)) return -ENOBUFS; iov[0].iov_base = buf; iov[0].iov_len = *len; return 1; } static void __user *io_ring_buffer_select(struct io_kiocb *req, size_t *len, struct io_buffer_list *bl, unsigned int issue_flags) { struct io_uring_buf_ring *br = bl->buf_ring; __u16 tail, head = bl->head; struct io_uring_buf *buf; void __user *ret; tail = smp_load_acquire(&br->tail); if (unlikely(tail == head)) return NULL; if (head + 1 == tail) req->flags |= REQ_F_BL_EMPTY; buf = io_ring_head_to_buf(br, head, bl->mask); if (*len == 0 || *len > buf->len) *len = buf->len; req->flags |= REQ_F_BUFFER_RING | REQ_F_BUFFERS_COMMIT; req->buf_list = bl; req->buf_index = buf->bid; ret = u64_to_user_ptr(buf->addr); if (issue_flags & IO_URING_F_UNLOCKED || !io_file_can_poll(req)) { /* * If we came in unlocked, we have no choice but to consume the * buffer here, otherwise nothing ensures that the buffer won't * get used by others. This does mean it'll be pinned until the * IO completes, coming in unlocked means we're being called from * io-wq context and there may be further retries in async hybrid * mode. For the locked case, the caller must call commit when * the transfer completes (or if we get -EAGAIN and must poll of * retry). */ io_kbuf_commit(req, bl, *len, 1); req->buf_list = NULL; } return ret; } void __user *io_buffer_select(struct io_kiocb *req, size_t *len, unsigned int issue_flags) { struct io_ring_ctx *ctx = req->ctx; struct io_buffer_list *bl; void __user *ret = NULL; io_ring_submit_lock(req->ctx, issue_flags); bl = io_buffer_get_list(ctx, req->buf_index); if (likely(bl)) { if (bl->flags & IOBL_BUF_RING) ret = io_ring_buffer_select(req, len, bl, issue_flags); else ret = io_provided_buffer_select(req, len, bl); } io_ring_submit_unlock(req->ctx, issue_flags); return ret; } /* cap it at a reasonable 256, will be one page even for 4K */ #define PEEK_MAX_IMPORT 256 static int io_ring_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg, struct io_buffer_list *bl) { struct io_uring_buf_ring *br = bl->buf_ring; struct iovec *iov = arg->iovs; int nr_iovs = arg->nr_iovs; __u16 nr_avail, tail, head; struct io_uring_buf *buf; tail = smp_load_acquire(&br->tail); head = bl->head; nr_avail = min_t(__u16, tail - head, UIO_MAXIOV); if (unlikely(!nr_avail)) return -ENOBUFS; buf = io_ring_head_to_buf(br, head, bl->mask); if (arg->max_len) { u32 len = READ_ONCE(buf->len); if (unlikely(!len)) return -ENOBUFS; /* * Limit incremental buffers to 1 segment. No point trying * to peek ahead and map more than we need, when the buffers * themselves should be large when setup with * IOU_PBUF_RING_INC. */ if (bl->flags & IOBL_INC) { nr_avail = 1; } else { size_t needed; needed = (arg->max_len + len - 1) / len; needed = min_not_zero(needed, (size_t) PEEK_MAX_IMPORT); if (nr_avail > needed) nr_avail = needed; } } /* * only alloc a bigger array if we know we have data to map, eg not * a speculative peek operation. */ if (arg->mode & KBUF_MODE_EXPAND && nr_avail > nr_iovs && arg->max_len) { iov = kmalloc_array(nr_avail, sizeof(struct iovec), GFP_KERNEL); if (unlikely(!iov)) return -ENOMEM; if (arg->mode & KBUF_MODE_FREE) kfree(arg->iovs); arg->iovs = iov; nr_iovs = nr_avail; } else if (nr_avail < nr_iovs) { nr_iovs = nr_avail; } /* set it to max, if not set, so we can use it unconditionally */ if (!arg->max_len) arg->max_len = INT_MAX; req->buf_index = buf->bid; do { u32 len = buf->len; /* truncate end piece, if needed, for non partial buffers */ if (len > arg->max_len) { len = arg->max_len; if (!(bl->flags & IOBL_INC)) buf->len = len; } iov->iov_base = u64_to_user_ptr(buf->addr); iov->iov_len = len; iov++; arg->out_len += len; arg->max_len -= len; if (!arg->max_len) break; buf = io_ring_head_to_buf(br, ++head, bl->mask); } while (--nr_iovs); if (head == tail) req->flags |= REQ_F_BL_EMPTY; req->flags |= REQ_F_BUFFER_RING; req->buf_list = bl; return iov - arg->iovs; } int io_buffers_select(struct io_kiocb *req, struct buf_sel_arg *arg, unsigned int issue_flags) { struct io_ring_ctx *ctx = req->ctx; struct io_buffer_list *bl; int ret = -ENOENT; io_ring_submit_lock(ctx, issue_flags); bl = io_buffer_get_list(ctx, req->buf_index); if (unlikely(!bl)) goto out_unlock; if (bl->flags & IOBL_BUF_RING) { ret = io_ring_buffers_peek(req, arg, bl); /* * Don't recycle these buffers if we need to go through poll. * Nobody else can use them anyway, and holding on to provided * buffers for a send/write operation would happen on the app * side anyway with normal buffers. Besides, we already * committed them, they cannot be put back in the queue. */ if (ret > 0) { req->flags |= REQ_F_BUFFERS_COMMIT | REQ_F_BL_NO_RECYCLE; io_kbuf_commit(req, bl, arg->out_len, ret); } } else { ret = io_provided_buffers_select(req, &arg->out_len, bl, arg->iovs); } out_unlock: io_ring_submit_unlock(ctx, issue_flags); return ret; } int io_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg) { struct io_ring_ctx *ctx = req->ctx; struct io_buffer_list *bl; int ret; lockdep_assert_held(&ctx->uring_lock); bl = io_buffer_get_list(ctx, req->buf_index); if (unlikely(!bl)) return -ENOENT; if (bl->flags & IOBL_BUF_RING) { ret = io_ring_buffers_peek(req, arg, bl); if (ret > 0) req->flags |= REQ_F_BUFFERS_COMMIT; return ret; } /* don't support multiple buffer selections for legacy */ return io_provided_buffers_select(req, &arg->max_len, bl, arg->iovs); } static int __io_remove_buffers(struct io_ring_ctx *ctx, struct io_buffer_list *bl, unsigned nbufs) { unsigned i = 0; /* shouldn't happen */ if (!nbufs) return 0; if (bl->flags & IOBL_BUF_RING) { i = bl->buf_ring->tail - bl->head; if (bl->buf_nr_pages) { int j; if (!(bl->flags & IOBL_MMAP)) { for (j = 0; j < bl->buf_nr_pages; j++) unpin_user_page(bl->buf_pages[j]); } io_pages_unmap(bl->buf_ring, &bl->buf_pages, &bl->buf_nr_pages, bl->flags & IOBL_MMAP); bl->flags &= ~IOBL_MMAP; } /* make sure it's seen as empty */ INIT_LIST_HEAD(&bl->buf_list); bl->flags &= ~IOBL_BUF_RING; return i; } /* protects io_buffers_cache */ lockdep_assert_held(&ctx->uring_lock); while (!list_empty(&bl->buf_list)) { struct io_buffer *nxt; nxt = list_first_entry(&bl->buf_list, struct io_buffer, list); list_move(&nxt->list, &ctx->io_buffers_cache); if (++i == nbufs) return i; cond_resched(); } return i; } void io_put_bl(struct io_ring_ctx *ctx, struct io_buffer_list *bl) { if (atomic_dec_and_test(&bl->refs)) { __io_remove_buffers(ctx, bl, -1U); kfree_rcu(bl, rcu); } } void io_destroy_buffers(struct io_ring_ctx *ctx) { struct io_buffer_list *bl; struct list_head *item, *tmp; struct io_buffer *buf; unsigned long index; xa_for_each(&ctx->io_bl_xa, index, bl) { xa_erase(&ctx->io_bl_xa, bl->bgid); io_put_bl(ctx, bl); } /* * Move deferred locked entries to cache before pruning */ spin_lock(&ctx->completion_lock); if (!list_empty(&ctx->io_buffers_comp)) list_splice_init(&ctx->io_buffers_comp, &ctx->io_buffers_cache); spin_unlock(&ctx->completion_lock); list_for_each_safe(item, tmp, &ctx->io_buffers_cache) { buf = list_entry(item, struct io_buffer, list); kmem_cache_free(io_buf_cachep, buf); } } int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf); u64 tmp; if (sqe->rw_flags || sqe->addr || sqe->len || sqe->off || sqe->splice_fd_in) return -EINVAL; tmp = READ_ONCE(sqe->fd); if (!tmp || tmp > MAX_BIDS_PER_BGID) return -EINVAL; memset(p, 0, sizeof(*p)); p->nbufs = tmp; p->bgid = READ_ONCE(sqe->buf_group); return 0; } int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags) { struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf); struct io_ring_ctx *ctx = req->ctx; struct io_buffer_list *bl; int ret = 0; io_ring_submit_lock(ctx, issue_flags); ret = -ENOENT; bl = io_buffer_get_list(ctx, p->bgid); if (bl) { ret = -EINVAL; /* can't use provide/remove buffers command on mapped buffers */ if (!(bl->flags & IOBL_BUF_RING)) ret = __io_remove_buffers(ctx, bl, p->nbufs); } io_ring_submit_unlock(ctx, issue_flags); if (ret < 0) req_set_fail(req); io_req_set_res(req, ret, 0); return IOU_OK; } int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { unsigned long size, tmp_check; struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf); u64 tmp; if (sqe->rw_flags || sqe->splice_fd_in) return -EINVAL; tmp = READ_ONCE(sqe->fd); if (!tmp || tmp > MAX_BIDS_PER_BGID) return -E2BIG; p->nbufs = tmp; p->addr = READ_ONCE(sqe->addr); p->len = READ_ONCE(sqe->len); if (check_mul_overflow((unsigned long)p->len, (unsigned long)p->nbufs, &size)) return -EOVERFLOW; if (check_add_overflow((unsigned long)p->addr, size, &tmp_check)) return -EOVERFLOW; size = (unsigned long)p->len * p->nbufs; if (!access_ok(u64_to_user_ptr(p->addr), size)) return -EFAULT; p->bgid = READ_ONCE(sqe->buf_group); tmp = READ_ONCE(sqe->off); if (tmp > USHRT_MAX) return -E2BIG; if (tmp + p->nbufs > MAX_BIDS_PER_BGID) return -EINVAL; p->bid = tmp; return 0; }