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>

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index c5a46d10afaa0910ed56be147db059b3682f95dd..3cfdf4091001f83d1f8a984d3018a877bde5caee 100644 (file)
--- 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);
 }
 
 /*