From 51aac424aef980a6238d4907a5bb5a411fa926eb Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Thu, 14 Oct 2021 16:10:17 +0100
Subject: [PATCH] io_uring: optimise io_import_iovec nonblock passing
Git-commit: 51aac424aef980a6238d4907a5bb5a411fa926eb
Patch-mainline: v5.16-rc1
References: bsc#1205205
First, change IO_URING_F_NONBLOCK to take sign bit of the int, so
checking for it can be turned into test + sign-based-jump, makes the
binary smaller and may be faster.
Then, instead of passing need_lock boolean into io_import_iovec() just
give it issue_flags, which is already stored somewhere. Saves some space
on stack, a couple of test + cmov operations and other conversions.
note: we still leave
force_nonblock = issue_flags & IO_URING_F_NONBLOCK
variable, but it's optimised out by the compiler into testing
issue_flags directly.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ee96547e692f6c975c229cd82fc721679571a734.1634144845.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
---
fs/io_uring.c | 47 +++++++++++++++++++++++++----------------------
1 file changed, 25 insertions(+), 22 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index bb5cd8715f61..0a0f84b28eba 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -198,8 +198,9 @@ struct io_rings {
};
enum io_uring_cmd_flags {
- IO_URING_F_NONBLOCK = 1,
- IO_URING_F_COMPLETE_DEFER = 2,
+ IO_URING_F_COMPLETE_DEFER = 1,
+ /* int's last bit, sign checks are usually faster than a bit test */
+ IO_URING_F_NONBLOCK = INT_MIN,
};
struct io_mapped_ubuf {
@@ -3037,10 +3038,11 @@ static void io_ring_submit_lock(struct io_ring_ctx *ctx, bool needs_lock)
}
static struct io_buffer *io_buffer_select(struct io_kiocb *req, size_t *len,
- int bgid, bool needs_lock)
+ int bgid, unsigned int issue_flags)
{
struct io_buffer *kbuf = req->kbuf;
struct io_buffer *head;
+ bool needs_lock = !(issue_flags & IO_URING_F_NONBLOCK);
if (req->flags & REQ_F_BUFFER_SELECTED)
return kbuf;
@@ -3072,13 +3074,13 @@ static struct io_buffer *io_buffer_select(struct io_kiocb *req, size_t *len,
}
static void __user *io_rw_buffer_select(struct io_kiocb *req, size_t *len,
- bool needs_lock)
+ unsigned int issue_flags)
{
struct io_buffer *kbuf;
u16 bgid;
bgid = req->buf_index;
- kbuf = io_buffer_select(req, len, bgid, needs_lock);
+ kbuf = io_buffer_select(req, len, bgid, issue_flags);
if (IS_ERR(kbuf))
return kbuf;
return u64_to_user_ptr(kbuf->addr);
@@ -3086,7 +3088,7 @@ static void __user *io_rw_buffer_select(struct io_kiocb *req, size_t *len,
#ifdef CONFIG_COMPAT
static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov,
- bool needs_lock)
+ unsigned int issue_flags)
{
struct compat_iovec __user *uiov;
compat_ssize_t clen;
@@ -3102,7 +3104,7 @@ static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov,
return -EINVAL;
len = clen;
- buf = io_rw_buffer_select(req, &len, needs_lock);
+ buf = io_rw_buffer_select(req, &len, issue_flags);
if (IS_ERR(buf))
return PTR_ERR(buf);
iov[0].iov_base = buf;
@@ -3112,7 +3114,7 @@ static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov,
#endif
static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
- bool needs_lock)
+ unsigned int issue_flags)
{
struct iovec __user *uiov = u64_to_user_ptr(req->rw.addr);
void __user *buf;
@@ -3124,7 +3126,7 @@ static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
len = iov[0].iov_len;
if (len < 0)
return -EINVAL;
- buf = io_rw_buffer_select(req, &len, needs_lock);
+ buf = io_rw_buffer_select(req, &len, issue_flags);
if (IS_ERR(buf))
return PTR_ERR(buf);
iov[0].iov_base = buf;
@@ -3133,7 +3135,7 @@ static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
}
static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
- bool needs_lock)
+ unsigned int issue_flags)
{
if (req->flags & REQ_F_BUFFER_SELECTED) {
struct io_buffer *kbuf = req->kbuf;
@@ -3147,14 +3149,14 @@ static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
#ifdef CONFIG_COMPAT
if (req->ctx->compat)
- return io_compat_import(req, iov, needs_lock);
+ return io_compat_import(req, iov, issue_flags);
#endif
- return __io_iov_buffer_select(req, iov, needs_lock);
+ return __io_iov_buffer_select(req, iov, issue_flags);
}
static int io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec,
- struct iov_iter *iter, bool needs_lock)
+ struct iov_iter *iter, unsigned int issue_flags)
{
void __user *buf = u64_to_user_ptr(req->rw.addr);
size_t sqe_len = req->rw.len;
@@ -3172,7 +3174,7 @@ static int io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec,
if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) {
if (req->flags & REQ_F_BUFFER_SELECT) {
- buf = io_rw_buffer_select(req, &sqe_len, needs_lock);
+ buf = io_rw_buffer_select(req, &sqe_len, issue_flags);
if (IS_ERR(buf))
return PTR_ERR(buf);
req->rw.len = sqe_len;
@@ -3184,7 +3186,7 @@ static int io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec,
}
if (req->flags & REQ_F_BUFFER_SELECT) {
- ret = io_iov_buffer_select(req, *iovec, needs_lock);
+ ret = io_iov_buffer_select(req, *iovec, issue_flags);
if (!ret)
iov_iter_init(iter, rw, *iovec, 1, (*iovec)->iov_len);
*iovec = NULL;
@@ -3323,7 +3325,8 @@ static inline int io_rw_prep_async(struct io_kiocb *req, int rw)
struct iovec *iov = iorw->s.fast_iov;
int ret;
- ret = io_import_iovec(rw, req, &iov, &iorw->s.iter, false);
+ /* submission path, ->uring_lock should already be taken */
+ ret = io_import_iovec(rw, req, &iov, &iorw->s.iter, IO_URING_F_NONBLOCK);
if (unlikely(ret < 0))
return ret;
@@ -3451,7 +3454,7 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags)
} else {
s = &__s;
iovec = s->fast_iov;
- ret = io_import_iovec(READ, req, &iovec, &s->iter, !force_nonblock);
+ ret = io_import_iovec(READ, req, &iovec, &s->iter, issue_flags);
if (ret < 0)
return ret;
@@ -3579,7 +3582,7 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags)
} else {
s = &__s;
iovec = s->fast_iov;
- ret = io_import_iovec(WRITE, req, &iovec, &s->iter, !force_nonblock);
+ ret = io_import_iovec(WRITE, req, &iovec, &s->iter, issue_flags);
if (ret < 0)
return ret;
iov_iter_save_state(&s->iter, &s->iter_state);
@@ -4902,11 +4905,11 @@ static int io_recvmsg_copy_hdr(struct io_kiocb *req,
}
static struct io_buffer *io_recv_buffer_select(struct io_kiocb *req,
- bool needs_lock)
+ unsigned int issue_flags)
{
struct io_sr_msg *sr = &req->sr_msg;
- return io_buffer_select(req, &sr->len, sr->bgid, needs_lock);
+ return io_buffer_select(req, &sr->len, sr->bgid, issue_flags);
}
static inline unsigned int io_put_recv_kbuf(struct io_kiocb *req)
@@ -4969,7 +4972,7 @@ static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
}
if (req->flags & REQ_F_BUFFER_SELECT) {
- kbuf = io_recv_buffer_select(req, !force_nonblock);
+ kbuf = io_recv_buffer_select(req, issue_flags);
if (IS_ERR(kbuf))
return PTR_ERR(kbuf);
kmsg->fast_iov[0].iov_base = u64_to_user_ptr(kbuf->addr);
@@ -5021,7 +5024,7 @@ static int io_recv(struct io_kiocb *req, unsigned int issue_flags)
return -ENOTSOCK;
if (req->flags & REQ_F_BUFFER_SELECT) {
- kbuf = io_recv_buffer_select(req, !force_nonblock);
+ kbuf = io_recv_buffer_select(req, issue_flags);
if (IS_ERR(kbuf))
return PTR_ERR(kbuf);
buf = u64_to_user_ptr(kbuf->addr);
--
2.35.3