io_uring: refactor rings_size nosqarray handling

A preparation patch inversing the IORING_SETUP_NO_SQARRAY check, this
way there is only one successful return path from the function, which
will be helpful later.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: isilence

io_uring/io_uring.c

@@ -2761,7 +2761,9 @@ unsigned long rings_size(unsigned int flags, unsigned int sq_entries,
 			 unsigned int cq_entries, size_t *sq_offset)
 {
 	struct io_rings *rings;
-	size_t off, sq_array_size;
+	size_t off;
+
+	*sq_offset = SIZE_MAX;
 
 	off = struct_size(rings, cqes, cq_entries);
 	if (off == SIZE_MAX)
@@ -2785,19 +2787,17 @@ unsigned long rings_size(unsigned int flags, unsigned int sq_entries,
 		return SIZE_MAX;
 #endif
 
-	if (flags & IORING_SETUP_NO_SQARRAY) {
-		*sq_offset = SIZE_MAX;
-		return off;
-	}
-
-	*sq_offset = off;
+	if (!(flags & IORING_SETUP_NO_SQARRAY)) {
+		size_t sq_array_size;
 
-	sq_array_size = array_size(sizeof(u32), sq_entries);
-	if (sq_array_size == SIZE_MAX)
-		return SIZE_MAX;
+		*sq_offset = off;
 
-	if (check_add_overflow(off, sq_array_size, &off))
-		return SIZE_MAX;
+		sq_array_size = array_size(sizeof(u32), sq_entries);
+		if (sq_array_size == SIZE_MAX)
+			return SIZE_MAX;
+		if (check_add_overflow(off, sq_array_size, &off))
+			return SIZE_MAX;
+	}
 
 	return off;
 }