io_uring: remove 'fname' from io_open structure

mainline inclusion
from mainline-5.6-rc1
commit f8748881
category: feature
bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=27
CVE: NA
---------------------------

We only use it internally in the prep functions for both statx and
openat, so we don't need it to be persistent across the request.
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Conflicts:
	fs/io_uring.c
[ commit c12cedf2("io_uring: add 'struct open_how'
 to the openat request context" is not applied ]
Signed-off-by: Nyangerkun <yangerkun@huawei.com>
Reviewed-by: Nzhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: NCheng Jian <cj.chengjian@huawei.com>

fs/io_uring.c

@@ -393,7 +393,6 @@ struct io_open {
 		umode_t			mode;
 		unsigned		mask;
 	};
-	const char __user		*fname;
 	struct filename			*filename;
 	struct statx __user		*buffer;
 	int				flags;
@@ -2467,6 +2466,7 @@ static int io_fallocate(struct io_kiocb *req, struct io_kiocb **nxt,
 
 static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
+	const char __user *fname;
 	int ret;
 
 	if (sqe->ioprio || sqe->buf_index)
@@ -2474,10 +2474,10 @@ static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 	req->open.dfd = READ_ONCE(sqe->fd);
 	req->open.mode = READ_ONCE(sqe->len);
-	req->open.fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
 	req->open.flags = READ_ONCE(sqe->open_flags);
 
-	req->open.filename = getname(req->open.fname);
+	req->open.filename = getname(fname);
 	if (IS_ERR(req->open.filename)) {
 		ret = PTR_ERR(req->open.filename);
 		req->open.filename = NULL;
@@ -2591,6 +2591,7 @@ static int io_fadvise(struct io_kiocb *req, struct io_kiocb **nxt,
 
 static int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
+	const char __user *fname;
 	unsigned lookup_flags;
 	int ret;
 
@@ -2599,14 +2600,14 @@ static int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 	req->open.dfd = READ_ONCE(sqe->fd);
 	req->open.mask = READ_ONCE(sqe->len);
-	req->open.fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
 	req->open.buffer = u64_to_user_ptr(READ_ONCE(sqe->addr2));
 	req->open.flags = READ_ONCE(sqe->statx_flags);
 
 	if (vfs_stat_set_lookup_flags(&lookup_flags, req->open.flags))
 		return -EINVAL;
 
-	req->open.filename = getname_flags(req->open.fname, lookup_flags, NULL);
+	req->open.filename = getname_flags(fname, lookup_flags, NULL);
 	if (IS_ERR(req->open.filename)) {
 		ret = PTR_ERR(req->open.filename);
 		req->open.filename = NULL;