#include "io_uring.h"
#include "opdef.h"
#include "kbuf.h"
-
-#define IO_BUFFER_LIST_BUF_PER_PAGE (PAGE_SIZE / sizeof(struct io_uring_buf))
+#include "memmap.h"
/* BIDs are addressed by a 16-bit field in a CQE */
#define MAX_BIDS_PER_BGID (1 << 16)
__u16 bid;
};
-struct io_buf_free {
- struct hlist_node list;
- void *mem;
- size_t size;
- int inuse;
-};
-
-static inline struct io_buffer_list *__io_buffer_get_list(struct io_ring_ctx *ctx,
- unsigned int bgid)
-{
- return xa_load(&ctx->io_bl_xa, bgid);
-}
-
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 __io_buffer_get_list(ctx, bgid);
+ return xa_load(&ctx->io_bl_xa, bgid);
}
static int io_buffer_add_list(struct io_ring_ctx *ctx,
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)
if (head + 1 == tail)
req->flags |= REQ_F_BL_EMPTY;
- head &= bl->mask;
- buf = &br->bufs[head];
+ 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->flags |= REQ_F_BUFFER_RING | REQ_F_BUFFERS_COMMIT;
req->buf_list = bl;
req->buf_index = buf->bid;
* 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 ret;
}
-/*
- * Mark the given mapped range as free for reuse
- */
-static void io_kbuf_mark_free(struct io_ring_ctx *ctx, struct io_buffer_list *bl)
+/* 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_buf_free *ibf;
+ 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) {
+ int needed;
+
+ needed = (arg->max_len + buf->len - 1) / buf->len;
+ needed = min(needed, 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;
- hlist_for_each_entry(ibf, &ctx->io_buf_list, list) {
- if (bl->buf_ring == ibf->mem) {
- ibf->inuse = 0;
- return;
+ 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;
+}
- /* can't happen... */
- WARN_ON_ONCE(1);
+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,
if (bl->is_buf_ring) {
i = bl->buf_ring->tail - bl->head;
- if (bl->is_mmap) {
- /*
- * io_kbuf_list_free() will free the page(s) at
- * ->release() time.
- */
- io_kbuf_mark_free(ctx, bl);
- bl->buf_ring = NULL;
- bl->is_mmap = 0;
- } else if (bl->buf_nr_pages) {
+ if (bl->buf_nr_pages) {
int j;
- for (j = 0; j < bl->buf_nr_pages; j++)
- unpin_user_page(bl->buf_pages[j]);
- kvfree(bl->buf_pages);
- vunmap(bl->buf_ring);
- bl->buf_pages = NULL;
- bl->buf_nr_pages = 0;
+ 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);
struct io_buffer_list *bl)
{
struct io_uring_buf_ring *br = NULL;
- int nr_pages, ret, i;
struct page **pages;
+ int nr_pages, ret;
pages = io_pin_pages(reg->ring_addr,
flex_array_size(br, bufs, reg->ring_entries),
bl->is_mmap = 0;
return 0;
error_unpin:
- for (i = 0; i < nr_pages; i++)
- unpin_user_page(pages[i]);
+ unpin_user_pages(pages, nr_pages);
kvfree(pages);
vunmap(br);
return ret;
}
-/*
- * See if we have a suitable region that we can reuse, rather than allocate
- * both a new io_buf_free and mem region again. We leave it on the list as
- * even a reused entry will need freeing at ring release.
- */
-static struct io_buf_free *io_lookup_buf_free_entry(struct io_ring_ctx *ctx,
- size_t ring_size)
-{
- struct io_buf_free *ibf, *best = NULL;
- size_t best_dist;
-
- hlist_for_each_entry(ibf, &ctx->io_buf_list, list) {
- size_t dist;
-
- if (ibf->inuse || ibf->size < ring_size)
- continue;
- dist = ibf->size - ring_size;
- if (!best || dist < best_dist) {
- best = ibf;
- if (!dist)
- break;
- best_dist = dist;
- }
- }
-
- return best;
-}
-
static int io_alloc_pbuf_ring(struct io_ring_ctx *ctx,
struct io_uring_buf_reg *reg,
struct io_buffer_list *bl)
{
- struct io_buf_free *ibf;
size_t ring_size;
- void *ptr;
ring_size = reg->ring_entries * sizeof(struct io_uring_buf_ring);
- /* Reuse existing entry, if we can */
- ibf = io_lookup_buf_free_entry(ctx, ring_size);
- if (!ibf) {
- ptr = io_mem_alloc(ring_size);
- if (IS_ERR(ptr))
- return PTR_ERR(ptr);
-
- /* Allocate and store deferred free entry */
- ibf = kmalloc(sizeof(*ibf), GFP_KERNEL_ACCOUNT);
- if (!ibf) {
- io_mem_free(ptr);
- return -ENOMEM;
- }
- ibf->mem = ptr;
- ibf->size = ring_size;
- hlist_add_head(&ibf->list, &ctx->io_buf_list);
- }
- ibf->inuse = 1;
- bl->buf_ring = ibf->mem;
+ bl->buf_ring = io_pages_map(&bl->buf_pages, &bl->buf_nr_pages, ring_size);
+ if (!bl->buf_ring)
+ return -ENOMEM;
+
bl->is_buf_ring = 1;
bl->is_mmap = 1;
return 0;
return ERR_PTR(-EINVAL);
}
-/*
- * Called at or after ->release(), free the mmap'ed buffers that we used
- * for memory mapped provided buffer rings.
- */
-void io_kbuf_mmap_list_free(struct io_ring_ctx *ctx)
+int io_pbuf_mmap(struct file *file, struct vm_area_struct *vma)
{
- struct io_buf_free *ibf;
- struct hlist_node *tmp;
+ struct io_ring_ctx *ctx = file->private_data;
+ loff_t pgoff = vma->vm_pgoff << PAGE_SHIFT;
+ struct io_buffer_list *bl;
+ int bgid, ret;
- hlist_for_each_entry_safe(ibf, tmp, &ctx->io_buf_list, list) {
- hlist_del(&ibf->list);
- io_mem_free(ibf->mem);
- kfree(ibf);
- }
+ 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;
}
projects / linux-2.6-block.git / blobdiff