io_uring: remove duplicated io_size from rw

stable inclusion
from stable-5.10.67
commit 9a4e7f9038660b7fd41280f9d97e6c722804bd1d
bugzilla: 182619 https://gitee.com/openeuler/kernel/issues/I4EWO7

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9a4e7f9038660b7fd41280f9d97e6c722804bd1d

--------------------------------

[ Upstream commit 632546c4 ]

io_size and iov_count in io_read() and io_write() hold the same value,
kill the last one.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

fs/io_uring.c

@@ -3416,7 +3416,6 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
 	struct iov_iter __iter, *iter = &__iter;
 	struct io_async_rw *rw = req->async_data;
 	ssize_t io_size, ret, ret2;
-	size_t iov_count;
 	bool no_async;
 
 	if (rw)
@@ -3425,8 +3424,7 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
 	ret = io_import_iovec(READ, req, &iovec, iter, !force_nonblock);
 	if (ret < 0)
 		return ret;
-	iov_count = iov_iter_count(iter);
-	io_size = iov_count;
+	io_size = iov_iter_count(iter);
 	req->result = io_size;
 	ret = 0;
 
@@ -3442,7 +3440,7 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
 	if (no_async)
 		goto copy_iov;
 
-	ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), iov_count);
+	ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), io_size);
 	if (unlikely(ret))
 		goto out_free;
 
@@ -3461,7 +3459,7 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
 		if (req->file->f_flags & O_NONBLOCK)
 			goto done;
 		/* some cases will consume bytes even on error returns */
-		iov_iter_revert(iter, iov_count - iov_iter_count(iter));
+		iov_iter_revert(iter, io_size - iov_iter_count(iter));
 		ret = 0;
 		goto copy_iov;
 	} else if (ret < 0) {
@@ -3545,7 +3543,6 @@ static int io_write(struct io_kiocb *req, bool force_nonblock,
 	struct kiocb *kiocb = &req->rw.kiocb;
 	struct iov_iter __iter, *iter = &__iter;
 	struct io_async_rw *rw = req->async_data;
-	size_t iov_count;
 	ssize_t ret, ret2, io_size;
 
 	if (rw)
@@ -3554,8 +3551,7 @@ static int io_write(struct io_kiocb *req, bool force_nonblock,
 	ret = io_import_iovec(WRITE, req, &iovec, iter, !force_nonblock);
 	if (ret < 0)
 		return ret;
-	iov_count = iov_iter_count(iter);
-	io_size = iov_count;
+	io_size = iov_iter_count(iter);
 	req->result = io_size;
 
 	/* Ensure we clear previously set non-block flag */
@@ -3573,7 +3569,7 @@ static int io_write(struct io_kiocb *req, bool force_nonblock,
 	    (req->flags & REQ_F_ISREG))
 		goto copy_iov;
 
-	ret = rw_verify_area(WRITE, req->file, io_kiocb_ppos(kiocb), iov_count);
+	ret = rw_verify_area(WRITE, req->file, io_kiocb_ppos(kiocb), io_size);
 	if (unlikely(ret))
 		goto out_free;
 
@@ -3616,7 +3612,7 @@ static int io_write(struct io_kiocb *req, bool force_nonblock,
 	} else {
 copy_iov:
 		/* some cases will consume bytes even on error returns */
-		iov_iter_revert(iter, iov_count - iov_iter_count(iter));
+		iov_iter_revert(iter, io_size - iov_iter_count(iter));
 		ret = io_setup_async_rw(req, iovec, inline_vecs, iter, false);
 		if (!ret)
 			return -EAGAIN;