The patch titled
Subject: mm: kvrealloc: properly document __GFP_ZERO behavior
has been added to the -mm mm-unstable branch. Its filename is
mm-kvmalloc-align-kvrealloc-with-krealloc-fix-3.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-kvmalloc-align-kvrealloc-with-krealloc-fix-3.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Danilo Krummrich <dakr@xxxxxxxxxx>
Subject: mm: kvrealloc: properly document __GFP_ZERO behavior
Date: Tue, 30 Jul 2024 20:49:44 +0200
Properly document that if __GFP_ZERO logic is requested, callers must
ensure that, starting with the initial memory allocation, every subsequent
call to this API for the same memory allocation is flagged with
__GFP_ZERO. Otherwise, it is possible that __GFP_ZERO is not fully
honored by this API.
Link: https://lkml.kernel.org/r/20240730185049.6244-5-dakr@xxxxxxxxxx
Signed-off-by: Danilo Krummrich <dakr@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/util.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
--- a/mm/util.c~mm-kvmalloc-align-kvrealloc-with-krealloc-fix-3
+++ a/mm/util.c
@@ -726,12 +726,17 @@ EXPORT_SYMBOL(kvfree_sensitive);
* @size: the size to reallocate
* @flags: the flags for the page level allocator
*
- * The contents of the object pointed to are preserved up to the lesser of the
- * new and old size (__GFP_ZERO flag is effectively ignored).
- *
* If @p is %NULL, kvrealloc() behaves exactly like kvmalloc(). If @size is 0
* and @p is not a %NULL pointer, the object pointed to is freed.
*
+ * If __GFP_ZERO logic is requested, callers must ensure that, starting with the
+ * initial memory allocation, every subsequent call to this API for the same
+ * memory allocation is flagged with __GFP_ZERO. Otherwise, it is possible that
+ * __GFP_ZERO is not fully honored by this API.
+ *
+ * In any case, the contents of the object pointed to are preserved up to the
+ * lesser of the new and old sizes.
+ *
* This function must not be called concurrently with itself or kvfree() for the
* same memory allocation.
*
_
Patches currently in -mm which might be from dakr@xxxxxxxxxx are
mm-vmalloc-implement-vrealloc.patch
mm-vmalloc-implement-vrealloc-fix.patch
mm-vmalloc-implement-vrealloc-fix-2.patch
mm-vmalloc-implement-vrealloc-fix-3.patch
mm-vmalloc-implement-vrealloc-fix-4.patch
mm-kvmalloc-align-kvrealloc-with-krealloc.patch
mm-kvmalloc-align-kvrealloc-with-krealloc-fix.patch
mm-kvmalloc-align-kvrealloc-with-krealloc-fix-2.patch
mm-kvmalloc-align-kvrealloc-with-krealloc-fix-3.patch
