e0ee967630
Harden the buffer peeking a bit, by adding a sanity check for it having
a valid size. Outside of that, arg->max_len is a size_t, though it's
only ever set to a 32-bit value (as it's governed by MAX_RW_COUNT).
Bump our needed check to a size_t so we know it fits. Finally, cap the
calculated needed iov value to the PEEK_MAX_IMPORT, which is the
maximum number of segments that should be peeked.
Fixes: 35c8711c8f
("io_uring/kbuf: add helpers for getting/peeking multiple buffers")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
831 lines
20 KiB
C
831 lines
20 KiB
C
// 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, 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, &ctx->io_buffers_comp);
|
|
spin_unlock(&ctx->completion_lock);
|
|
} else {
|
|
lockdep_assert_held(&req->ctx->uring_lock);
|
|
|
|
__io_put_kbuf_list(req, &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 0;
|
|
}
|
|
|
|
static struct io_uring_buf *io_ring_head_to_buf(struct io_uring_buf_ring *br,
|
|
__u16 head, __u16 mask)
|
|
{
|
|
return &br->bufs[head & mask];
|
|
}
|
|
|
|
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;
|
|
|
|
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;
|
|
|
|
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).
|
|
*/
|
|
req->flags &= ~REQ_F_BUFFERS_COMMIT;
|
|
req->buf_list = NULL;
|
|
bl->head++;
|
|
}
|
|
return u64_to_user_ptr(buf->addr);
|
|
}
|
|
|
|
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->is_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);
|
|
size_t needed;
|
|
|
|
if (unlikely(!len))
|
|
return -ENOBUFS;
|
|
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 {
|
|
/* truncate end piece, if needed */
|
|
if (buf->len > arg->max_len)
|
|
buf->len = arg->max_len;
|
|
|
|
iov->iov_base = u64_to_user_ptr(buf->addr);
|
|
iov->iov_len = buf->len;
|
|
iov++;
|
|
|
|
arg->out_len += buf->len;
|
|
arg->max_len -= buf->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->is_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_BL_NO_RECYCLE;
|
|
req->buf_list->head += 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->is_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->is_buf_ring) {
|
|
i = bl->buf_ring->tail - bl->head;
|
|
if (bl->buf_nr_pages) {
|
|
int j;
|
|
|
|
if (!bl->is_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->is_mmap);
|
|
bl->is_mmap = 0;
|
|
}
|
|
/* make sure it's seen as empty */
|
|
INIT_LIST_HEAD(&bl->buf_list);
|
|
bl->is_buf_ring = 0;
|
|
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->is_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;
|
|
}
|
|
|
|
#define IO_BUFFER_ALLOC_BATCH 64
|
|
|
|
static int io_refill_buffer_cache(struct io_ring_ctx *ctx)
|
|
{
|
|
struct io_buffer *bufs[IO_BUFFER_ALLOC_BATCH];
|
|
int allocated;
|
|
|
|
/*
|
|
* Completions that don't happen inline (eg not under uring_lock) will
|
|
* add to ->io_buffers_comp. If we don't have any free buffers, check
|
|
* the completion list and splice those entries first.
|
|
*/
|
|
if (!list_empty_careful(&ctx->io_buffers_comp)) {
|
|
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);
|
|
return 0;
|
|
}
|
|
spin_unlock(&ctx->completion_lock);
|
|
}
|
|
|
|
/*
|
|
* No free buffers and no completion entries either. Allocate a new
|
|
* batch of buffer entries and add those to our freelist.
|
|
*/
|
|
|
|
allocated = kmem_cache_alloc_bulk(io_buf_cachep, GFP_KERNEL_ACCOUNT,
|
|
ARRAY_SIZE(bufs), (void **) bufs);
|
|
if (unlikely(!allocated)) {
|
|
/*
|
|
* Bulk alloc is all-or-nothing. If we fail to get a batch,
|
|
* retry single alloc to be on the safe side.
|
|
*/
|
|
bufs[0] = kmem_cache_alloc(io_buf_cachep, GFP_KERNEL);
|
|
if (!bufs[0])
|
|
return -ENOMEM;
|
|
allocated = 1;
|
|
}
|
|
|
|
while (allocated)
|
|
list_add_tail(&bufs[--allocated]->list, &ctx->io_buffers_cache);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int io_add_buffers(struct io_ring_ctx *ctx, struct io_provide_buf *pbuf,
|
|
struct io_buffer_list *bl)
|
|
{
|
|
struct io_buffer *buf;
|
|
u64 addr = pbuf->addr;
|
|
int i, bid = pbuf->bid;
|
|
|
|
for (i = 0; i < pbuf->nbufs; i++) {
|
|
if (list_empty(&ctx->io_buffers_cache) &&
|
|
io_refill_buffer_cache(ctx))
|
|
break;
|
|
buf = list_first_entry(&ctx->io_buffers_cache, struct io_buffer,
|
|
list);
|
|
list_move_tail(&buf->list, &bl->buf_list);
|
|
buf->addr = addr;
|
|
buf->len = min_t(__u32, pbuf->len, MAX_RW_COUNT);
|
|
buf->bid = bid;
|
|
buf->bgid = pbuf->bgid;
|
|
addr += pbuf->len;
|
|
bid++;
|
|
cond_resched();
|
|
}
|
|
|
|
return i ? 0 : -ENOMEM;
|
|
}
|
|
|
|
int io_provide_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);
|
|
|
|
bl = io_buffer_get_list(ctx, p->bgid);
|
|
if (unlikely(!bl)) {
|
|
bl = kzalloc(sizeof(*bl), GFP_KERNEL_ACCOUNT);
|
|
if (!bl) {
|
|
ret = -ENOMEM;
|
|
goto err;
|
|
}
|
|
INIT_LIST_HEAD(&bl->buf_list);
|
|
ret = io_buffer_add_list(ctx, bl, p->bgid);
|
|
if (ret) {
|
|
/*
|
|
* Doesn't need rcu free as it was never visible, but
|
|
* let's keep it consistent throughout.
|
|
*/
|
|
kfree_rcu(bl, rcu);
|
|
goto err;
|
|
}
|
|
}
|
|
/* can't add buffers via this command for a mapped buffer ring */
|
|
if (bl->is_buf_ring) {
|
|
ret = -EINVAL;
|
|
goto err;
|
|
}
|
|
|
|
ret = io_add_buffers(ctx, p, bl);
|
|
err:
|
|
io_ring_submit_unlock(ctx, issue_flags);
|
|
|
|
if (ret < 0)
|
|
req_set_fail(req);
|
|
io_req_set_res(req, ret, 0);
|
|
return IOU_OK;
|
|
}
|
|
|
|
static int io_pin_pbuf_ring(struct io_uring_buf_reg *reg,
|
|
struct io_buffer_list *bl)
|
|
{
|
|
struct io_uring_buf_ring *br = NULL;
|
|
struct page **pages;
|
|
int nr_pages, ret;
|
|
|
|
pages = io_pin_pages(reg->ring_addr,
|
|
flex_array_size(br, bufs, reg->ring_entries),
|
|
&nr_pages);
|
|
if (IS_ERR(pages))
|
|
return PTR_ERR(pages);
|
|
|
|
br = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
|
|
if (!br) {
|
|
ret = -ENOMEM;
|
|
goto error_unpin;
|
|
}
|
|
|
|
#ifdef SHM_COLOUR
|
|
/*
|
|
* On platforms that have specific aliasing requirements, SHM_COLOUR
|
|
* is set and we must guarantee that the kernel and user side align
|
|
* nicely. We cannot do that if IOU_PBUF_RING_MMAP isn't set and
|
|
* the application mmap's the provided ring buffer. Fail the request
|
|
* if we, by chance, don't end up with aligned addresses. The app
|
|
* should use IOU_PBUF_RING_MMAP instead, and liburing will handle
|
|
* this transparently.
|
|
*/
|
|
if ((reg->ring_addr | (unsigned long) br) & (SHM_COLOUR - 1)) {
|
|
ret = -EINVAL;
|
|
goto error_unpin;
|
|
}
|
|
#endif
|
|
bl->buf_pages = pages;
|
|
bl->buf_nr_pages = nr_pages;
|
|
bl->buf_ring = br;
|
|
bl->is_buf_ring = 1;
|
|
bl->is_mmap = 0;
|
|
return 0;
|
|
error_unpin:
|
|
unpin_user_pages(pages, nr_pages);
|
|
kvfree(pages);
|
|
vunmap(br);
|
|
return ret;
|
|
}
|
|
|
|
static int io_alloc_pbuf_ring(struct io_ring_ctx *ctx,
|
|
struct io_uring_buf_reg *reg,
|
|
struct io_buffer_list *bl)
|
|
{
|
|
size_t ring_size;
|
|
|
|
ring_size = reg->ring_entries * sizeof(struct io_uring_buf_ring);
|
|
|
|
bl->buf_ring = io_pages_map(&bl->buf_pages, &bl->buf_nr_pages, ring_size);
|
|
if (IS_ERR(bl->buf_ring)) {
|
|
bl->buf_ring = NULL;
|
|
return -ENOMEM;
|
|
}
|
|
|
|
bl->is_buf_ring = 1;
|
|
bl->is_mmap = 1;
|
|
return 0;
|
|
}
|
|
|
|
int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
|
|
{
|
|
struct io_uring_buf_reg reg;
|
|
struct io_buffer_list *bl, *free_bl = NULL;
|
|
int ret;
|
|
|
|
lockdep_assert_held(&ctx->uring_lock);
|
|
|
|
if (copy_from_user(®, arg, sizeof(reg)))
|
|
return -EFAULT;
|
|
|
|
if (reg.resv[0] || reg.resv[1] || reg.resv[2])
|
|
return -EINVAL;
|
|
if (reg.flags & ~IOU_PBUF_RING_MMAP)
|
|
return -EINVAL;
|
|
if (!(reg.flags & IOU_PBUF_RING_MMAP)) {
|
|
if (!reg.ring_addr)
|
|
return -EFAULT;
|
|
if (reg.ring_addr & ~PAGE_MASK)
|
|
return -EINVAL;
|
|
} else {
|
|
if (reg.ring_addr)
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (!is_power_of_2(reg.ring_entries))
|
|
return -EINVAL;
|
|
|
|
/* cannot disambiguate full vs empty due to head/tail size */
|
|
if (reg.ring_entries >= 65536)
|
|
return -EINVAL;
|
|
|
|
bl = io_buffer_get_list(ctx, reg.bgid);
|
|
if (bl) {
|
|
/* if mapped buffer ring OR classic exists, don't allow */
|
|
if (bl->is_buf_ring || !list_empty(&bl->buf_list))
|
|
return -EEXIST;
|
|
} else {
|
|
free_bl = bl = kzalloc(sizeof(*bl), GFP_KERNEL);
|
|
if (!bl)
|
|
return -ENOMEM;
|
|
}
|
|
|
|
if (!(reg.flags & IOU_PBUF_RING_MMAP))
|
|
ret = io_pin_pbuf_ring(®, bl);
|
|
else
|
|
ret = io_alloc_pbuf_ring(ctx, ®, bl);
|
|
|
|
if (!ret) {
|
|
bl->nr_entries = reg.ring_entries;
|
|
bl->mask = reg.ring_entries - 1;
|
|
|
|
io_buffer_add_list(ctx, bl, reg.bgid);
|
|
return 0;
|
|
}
|
|
|
|
kfree_rcu(free_bl, rcu);
|
|
return ret;
|
|
}
|
|
|
|
int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
|
|
{
|
|
struct io_uring_buf_reg reg;
|
|
struct io_buffer_list *bl;
|
|
|
|
lockdep_assert_held(&ctx->uring_lock);
|
|
|
|
if (copy_from_user(®, arg, sizeof(reg)))
|
|
return -EFAULT;
|
|
if (reg.resv[0] || reg.resv[1] || reg.resv[2])
|
|
return -EINVAL;
|
|
if (reg.flags)
|
|
return -EINVAL;
|
|
|
|
bl = io_buffer_get_list(ctx, reg.bgid);
|
|
if (!bl)
|
|
return -ENOENT;
|
|
if (!bl->is_buf_ring)
|
|
return -EINVAL;
|
|
|
|
xa_erase(&ctx->io_bl_xa, bl->bgid);
|
|
io_put_bl(ctx, bl);
|
|
return 0;
|
|
}
|
|
|
|
int io_register_pbuf_status(struct io_ring_ctx *ctx, void __user *arg)
|
|
{
|
|
struct io_uring_buf_status buf_status;
|
|
struct io_buffer_list *bl;
|
|
int i;
|
|
|
|
if (copy_from_user(&buf_status, arg, sizeof(buf_status)))
|
|
return -EFAULT;
|
|
|
|
for (i = 0; i < ARRAY_SIZE(buf_status.resv); i++)
|
|
if (buf_status.resv[i])
|
|
return -EINVAL;
|
|
|
|
bl = io_buffer_get_list(ctx, buf_status.buf_group);
|
|
if (!bl)
|
|
return -ENOENT;
|
|
if (!bl->is_buf_ring)
|
|
return -EINVAL;
|
|
|
|
buf_status.head = bl->head;
|
|
if (copy_to_user(arg, &buf_status, sizeof(buf_status)))
|
|
return -EFAULT;
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct io_buffer_list *io_pbuf_get_bl(struct io_ring_ctx *ctx,
|
|
unsigned long bgid)
|
|
{
|
|
struct io_buffer_list *bl;
|
|
bool ret;
|
|
|
|
/*
|
|
* We have to be a bit careful here - we're inside mmap and cannot grab
|
|
* the uring_lock. This means the buffer_list could be simultaneously
|
|
* going away, if someone is trying to be sneaky. Look it up under rcu
|
|
* so we know it's not going away, and attempt to grab a reference to
|
|
* it. If the ref is already zero, then fail the mapping. If successful,
|
|
* the caller will call io_put_bl() to drop the the reference at at the
|
|
* end. This may then safely free the buffer_list (and drop the pages)
|
|
* at that point, vm_insert_pages() would've already grabbed the
|
|
* necessary vma references.
|
|
*/
|
|
rcu_read_lock();
|
|
bl = xa_load(&ctx->io_bl_xa, bgid);
|
|
/* must be a mmap'able buffer ring and have pages */
|
|
ret = false;
|
|
if (bl && bl->is_mmap)
|
|
ret = atomic_inc_not_zero(&bl->refs);
|
|
rcu_read_unlock();
|
|
|
|
if (ret)
|
|
return bl;
|
|
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
int io_pbuf_mmap(struct file *file, struct vm_area_struct *vma)
|
|
{
|
|
struct io_ring_ctx *ctx = file->private_data;
|
|
loff_t pgoff = vma->vm_pgoff << PAGE_SHIFT;
|
|
struct io_buffer_list *bl;
|
|
int bgid, ret;
|
|
|
|
bgid = (pgoff & ~IORING_OFF_MMAP_MASK) >> IORING_OFF_PBUF_SHIFT;
|
|
bl = io_pbuf_get_bl(ctx, bgid);
|
|
if (IS_ERR(bl))
|
|
return PTR_ERR(bl);
|
|
|
|
ret = io_uring_mmap_pages(ctx, vma, bl->buf_pages, bl->buf_nr_pages);
|
|
io_put_bl(ctx, bl);
|
|
return ret;
|
|
}
|