io_uring/tctx: avoid modifying loop variable in io_ring_add_registered_file

Use a separate 'idx' variable to store the result of array_index_nospec()
instead of modifying the loop variable 'offset' directly. This improves
code clarity by separating the logical index from the sanitized index
used for array access.

No functional change intended.

Signed-off-by: Yang Xiuwei <yangxiuwei@kylinos.cn>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Yang Xiuwei

io_uring/tctx.c

@@ -240,14 +240,14 @@ void io_uring_unreg_ringfd(void)
 int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file,
 				     int start, int end)
 {
-	int offset;
+	int offset, idx;
 	for (offset = start; offset < end; offset++) {
-		offset = array_index_nospec(offset, IO_RINGFD_REG_MAX);
-		if (tctx->registered_rings[offset])
+		idx = array_index_nospec(offset, IO_RINGFD_REG_MAX);
+		if (tctx->registered_rings[idx])
 			continue;
 
-		tctx->registered_rings[offset] = file;
-		return offset;
+		tctx->registered_rings[idx] = file;
+		return idx;
 	}
 	return -EBUSY;
 }