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From: Nhat Pham <nphamcs@gmail.com>
To: akpm@linux-foundation.org
Cc: hannes@cmpxchg.org, yosryahmed@google.com, yosry.ahmed@linux.dev,
	chengming.zhou@linux.dev, linux-mm@kvack.org,
	kernel-team@meta.com, linux-kernel@vger.kernel.org
Subject: [PATCH] page_io: return proper error codes for swap_read_folio_zeromap() (fix)
Date: Fri,  7 Mar 2025 15:34:22 -0800	[thread overview]
Message-ID: <20250307233422.658954-1-nphamcs@gmail.com> (raw)
In-Reply-To: <20250306230015.1456794-1-nphamcs@gmail.com>

Fix the comments for swap_read_folio_zeromap().

Suggested-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
---
 mm/page_io.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/mm/page_io.c b/mm/page_io.c
index 48ed1e810392..30ec132c801b 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -521,9 +521,8 @@ static void sio_read_complete(struct kiocb *iocb, long ret)
  *
  *  -ENOENT: the folio is entirely not zeromapped. The folio remains locked.
  *
- *  -EINVAL: some of the subpages in the folio are zeromaped, but not all of
- *  them. This is an error because we don't currently support a large folio
- *  that is partially in the zeromap. The folio is unlocked, but NOT marked
+ *  -EINVAL: The folio is partially in the zeromap, which is not
+ *  currently supported. The folio is unlocked, but NOT marked
  *  up-to-date, so that an IO error is emitted (e.g. do_swap_page() will
  *  sigbus).
  */
@@ -533,11 +532,6 @@ static int swap_read_folio_zeromap(struct folio *folio)
 	struct obj_cgroup *objcg;
 	bool is_zeromap;
 
-	/*
-	 * Swapping in a large folio that is partially in the zeromap is not
-	 * currently handled. Return -EINVAL without marking the folio uptodate so
-	 * that an IO error is emitted (e.g. do_swap_page() will sigbus).
-	 */
 	if (WARN_ON_ONCE(swap_zeromap_batch(folio->swap, nr_pages,
 			&is_zeromap) != nr_pages)) {
 		folio_unlock(folio);
-- 
2.43.5



  parent reply	other threads:[~2025-03-07 23:34 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-06 23:00 [PATCH] page_io: return proper error codes for swap_read_folio_zeromap() Nhat Pham
2025-03-06 23:42 ` Yosry Ahmed
2025-03-07 17:03   ` Nhat Pham
2025-03-07  1:38 ` Johannes Weiner
2025-03-07  3:08 ` Chengming Zhou
2025-03-07 23:34 ` Nhat Pham [this message]
2025-04-01 18:55 ` Nhat Pham
2025-04-01 19:01   ` Andrew Morton

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