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io_uring: eliminate the need to track provided buffer ID separately

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We have io_kiocb->buf_index which is used for either fixed buffers, or
for provided buffers. For the latter, it's used to hold the buffer group
ID for buffer selection. Post selection, req->kbuf->bid is used to get
the buffer ID.

Store the buffer ID, when selected, in req->buf_index. If we do end up
recycling the buffer, reset it back to the buffer group ID.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2022-05-01 12:08:35 -06:00
parent 660cbfa234
commit 1dbd023eb0
1 changed files with 10 additions and 6 deletions
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16
fs/io_uring.c
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@ -951,6 +951,11 @@ struct io_kiocb {
u8 opcode;
/* polled IO has completed */
u8 iopoll_completed;
/*
* Can be either a fixed buffer index, or used with provided buffers.
* For the latter, before issue it points to the buffer group ID,
* and after selection it points to the buffer ID itself.
*/
u16 buf_index;
unsigned int flags;
@ -1456,14 +1461,11 @@ static inline void io_req_set_rsrc_node(struct io_kiocb *req,
static unsigned int __io_put_kbuf(struct io_kiocb *req, struct list_head *list)
{
struct io_buffer *kbuf = req->kbuf;
unsigned int cflags;
cflags = IORING_CQE_F_BUFFER | (kbuf->bid << IORING_CQE_BUFFER_SHIFT);
req->flags &= ~REQ_F_BUFFER_SELECTED;
list_add(&kbuf->list, list);
list_add(&req->kbuf->list, list);
req->kbuf = NULL;
return cflags;
return IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT);
}
static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req)
@ -1537,6 +1539,7 @@ static void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
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;
req->kbuf = NULL;
io_ring_submit_unlock(ctx, issue_flags);
@ -3469,6 +3472,7 @@ static void __user *io_provided_buffer_select(struct io_kiocb *req, size_t *len,
*len = kbuf->len;
req->flags |= REQ_F_BUFFER_SELECTED;
req->kbuf = kbuf;
req->buf_index = kbuf->bid;
io_ring_submit_unlock(req->ctx, issue_flags);
return u64_to_user_ptr(kbuf->addr);
}