Cleanup: Simplify userspace abd_free_chunks()

Clang's static analyzer complained that we could use after free here if the inner loop ever iterated. That is a false positive, but upon inspection, the userland abd_alloc_chunks() function never will put multiple consecutive pages into a `struct scatterlist`, so there is no need to loop. We delete the inner loop. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Richard Yao <[email protected]> Closes openzfs#14042
andrewc12 · Nov 9, 2022 · 96217d6 · 96217d6
1 parent 57ffd98
commit 96217d6
Showing 1 changed file with 2 additions and 4 deletions.
diff --git a/module/os/linux/zfs/abd_os.c b/module/os/linux/zfs/abd_os.c
@@ -597,10 +597,8 @@ abd_free_chunks(abd_t *abd)
 	struct scatterlist *sg;
 
 	abd_for_each_sg(abd, sg, n, i) {
-		for (int j = 0; j < sg->length; j += PAGESIZE) {
-			struct page *p = nth_page(sg_page(sg), j >> PAGE_SHIFT);
-			umem_free_aligned(p, PAGESIZE);
-		}
+		struct page *p = nth_page(sg_page(sg), 0);
+		umem_free_aligned(p, PAGESIZE);
 	}
 	abd_free_sg_table(abd);
 }