Thread (41 messages) 41 messages, 8 authors, 2024-12-17

Re: [PATCH v3 17/25] gup: Don't allow FOLL_LONGTERM pinning of FS DAX pages

From: John Hubbard <jhubbard@nvidia.com>
Date: 2024-11-22 03:23:47
Also in: linux-arm-kernel, linux-cxl, linux-doc, linux-ext4, linux-fsdevel, linux-mm, linux-xfs, lkml, nvdimm

On 11/21/24 5:40 PM, Alistair Popple wrote:
quoted hunk ↗ jump to hunk
Longterm pinning of FS DAX pages should already be disallowed by
various pXX_devmap checks. However a future change will cause these
checks to be invalid for FS DAX pages so make
folio_is_longterm_pinnable() return false for FS DAX pages.

Signed-off-by: Alistair Popple <apopple@nvidia.com>
---
  include/linux/mm.h | 4 ++++
  1 file changed, 4 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 22c651b..4f9ae37 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2004,6 +2004,10 @@ static inline bool folio_is_longterm_pinnable(struct folio *folio)
  	if (folio_is_device_coherent(folio))
  		return false;
  
+	/* DAX must also always allow eviction. */
+	if (folio_is_fsdax(folio))
+		return false;
+
  	/* Otherwise, non-movable zone folios can be pinned. */
  	return !folio_is_zone_movable(folio);
  
Reviewed-by: John Hubbard <jhubbard@nvidia.com>


thanks,
-- 
John Hubbard

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