fs: hugetlbfs: cleanup folio in adjust_range_hwpoison()

Let's cleanup and simplify the function a bit.

Link: https://lkml.kernel.org/r/20250901150359.867252-17-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 12 insertions, 24 deletions

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index c5a46d10afaa..3cfdf4091001 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -192,37 +192,25 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
  * Someone wants to read @bytes from a HWPOISON hugetlb @folio from @offset.
  * Returns the maximum number of bytes one can read without touching the 1st raw
  * HWPOISON page.
- *
- * The implementation borrows the iteration logic from copy_page_to_iter*.
  */
 static size_t adjust_range_hwpoison(struct folio *folio, size_t offset,
 		size_t bytes)
 {
-	struct page *page;
-	size_t n = 0;
-	size_t res = 0;
-
-	/* First page to start the loop. */
-	page = folio_page(folio, offset / PAGE_SIZE);
-	offset %= PAGE_SIZE;
-	while (1) {
-		if (is_raw_hwpoison_page_in_hugepage(page))
-			break;
+	struct page *page = folio_page(folio, offset / PAGE_SIZE);
+	size_t safe_bytes;
+
+	if (is_raw_hwpoison_page_in_hugepage(page))
+		return 0;
+	/* Safe to read the remaining bytes in this page. */
+	safe_bytes = PAGE_SIZE - (offset % PAGE_SIZE);
+	page++;
 
-		/* Safe to read n bytes without touching HWPOISON subpage. */
-		n = min(bytes, (size_t)PAGE_SIZE - offset);
-		res += n;
-		bytes -= n;
-		if (!bytes || !n)
+	/* Check each remaining page as long as we are not done yet. */
+	for (; safe_bytes < bytes; safe_bytes += PAGE_SIZE, page++)
+		if (is_raw_hwpoison_page_in_hugepage(page))
 			break;
-		offset += n;
-		if (offset == PAGE_SIZE) {
-			page++;
-			offset = 0;
-		}
-	}
 
-	return res;
+	return min(safe_bytes, bytes);
 }
 
 /*