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io_uring: optimise io_import_iovec fixed path

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Delay loading req->rw.{addr,len} in io_import_iovec until it's really
needed, so removing extra loads for the fixed path, which doesn't use
them.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3cc48dd0c4f1a37c4ce9aab5784281a2d83ad8be.1634314022.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2021-10-15 17:09:13 +01:00 committed by Jens Axboe
parent 9882131cd9
commit d1d681b084
1 changed files with 6 additions and 3 deletions
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9
fs/io_uring.c
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@ -3159,9 +3159,9 @@ static int __io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec,
struct io_rw_state *s, unsigned int issue_flags)
{
struct iov_iter *iter = &s->iter;
void __user *buf = u64_to_user_ptr(req->rw.addr);
size_t sqe_len = req->rw.len;
u8 opcode = req->opcode;
void __user *buf;
size_t sqe_len;
ssize_t ret;
if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
@ -3170,9 +3170,12 @@ static int __io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec,
}
/* buffer index only valid with fixed read/write, or buffer select */
if (req->buf_index && !(req->flags & REQ_F_BUFFER_SELECT))
if (unlikely(req->buf_index && !(req->flags & REQ_F_BUFFER_SELECT)))
return -EINVAL;
buf = u64_to_user_ptr(req->rw.addr);
sqe_len = req->rw.len;
if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) {
if (req->flags & REQ_F_BUFFER_SELECT) {
buf = io_rw_buffer_select(req, &sqe_len, issue_flags);