[PATCH] io_uring: Fix incorrect variable type in io_fixed_fd_install

[PATCH] io_uring: Fix incorrect variable type in io_fixed_fd_install

[Wan Jiabing]

Fix following coccicheck warning:
fs/io_uring.c:5352:15-24: WARNING: Unsigned expression compared with zero: file_slot < 0

'file_slot' is an unsigned variable and it can't be less than 0.
Use 'ret' instead to check the error code from io_file_bitmap_get().

And using bool to declare 'alloc_slot' makes the code better.  

Fixes: 08cf52bc6eb4 ("io_uring: allow allocated fixed files for openat/openat2")
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
---
 fs/io_uring.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index e8f5106434ad..92d0321bdefe 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5342,17 +5342,19 @@ static int io_file_bitmap_get(struct io_ring_ctx *ctx)
 static int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags,
 			       struct file *file, unsigned int file_slot)
 {
-	int alloc_slot = file_slot == IORING_FILE_INDEX_ALLOC;
+	bool alloc_slot = file_slot == IORING_FILE_INDEX_ALLOC;
 	struct io_ring_ctx *ctx = req->ctx;
 	int ret;
 
 	if (alloc_slot) {
 		io_ring_submit_lock(ctx, issue_flags);
-		file_slot = io_file_bitmap_get(ctx);
-		if (unlikely(file_slot < 0)) {
+		ret = io_file_bitmap_get(ctx);
+		if (unlikely(ret < 0)) {
 			io_ring_submit_unlock(ctx, issue_flags);
-			return file_slot;
+			return ret;
 		}
+
+		file_slot = ret;
 	}
 
 	ret = io_install_fixed_file(req, file, issue_flags, file_slot);
-- 
2.35.1

Re: [PATCH] io_uring: Fix incorrect variable type in io_fixed_fd_install

[Jens Axboe]

On 5/12/22 6:05 AM, Wan Jiabing wrote:
> Fix following coccicheck warning:
> fs/io_uring.c:5352:15-24: WARNING: Unsigned expression compared with zero: file_slot < 0
> 
> 'file_slot' is an unsigned variable and it can't be less than 0.
> Use 'ret' instead to check the error code from io_file_bitmap_get().
> 
> And using bool to declare 'alloc_slot' makes the code better.  

Thanks, I'm going to fold this one in.

-- 
Jens Axboe