From: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
To: "Lorenzo Stoakes (Oracle)" <ljs@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@kernel.org>,
"Liam R . Howlett" <Liam.Howlett@oracle.com>,
Jann Horn <jannh@google.com>, Pedro Falcato <pfalcato@suse.de>,
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Suren Baghdasaryan <surenb@google.com>,
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Vineet Gupta <vgupta@kernel.org>,
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Huacai Chen <chenhuacai@kernel.org>,
WANG Xuerui <kernel@xen0n.name>,
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Subject: Re: [PATCH v4 25/25] mm: simplify VMA flag tests of excluded flags
Date: Mon, 23 Mar 2026 16:51:41 +0100 [thread overview]
Message-ID: <47f796ed-ac66-4a75-98c9-64afc8929f35@kernel.org> (raw)
In-Reply-To: <d395c5dd837a9864f5efcec42175910afbe3ce73.1774034900.git.ljs@kernel.org>
On 3/20/26 8:38 PM, Lorenzo Stoakes (Oracle) wrote:
> We have implemented flag mask comparisons of the form:
>
> if ((vm_flags & (VM_FOO|VM_BAR|VM_BAZ) == VM_FOO) { ... }
>
> Like-for-like in the code using a bitwise-and mask via vma_flags_and() and
> using vma_flags_same() to ensure the final result equals only the required
> flag value.
>
> This is fine but confusing, make things clearer by instead explicitly
> excluding undesired flags and including the desired one via tests of the
> form:
>
> if (vma_flags_test(&flags, VMA_FOO_BIT) &&
> !vma_flags_test_any(&flags, VMA_BAR_BIT, VMA_BAZ_BIT)) { ... }
>
> Which makes it easier to understand what is going on.
>
> No functional change intended.
>
> Suggested-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
> Signed-off-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
next prev parent reply other threads:[~2026-03-23 15:51 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-20 19:38 [PATCH v4 00/25] mm/vma: convert vm_flags_t to vma_flags_t in vma code Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 01/25] mm/vma: add vma_flags_empty(), vma_flags_and(), vma_flags_diff_pair() Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 02/25] tools/testing/vma: add unit tests flag empty, diff_pair, and[_mask] Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 03/25] mm/vma: add further vma_flags_t unions Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 04/25] tools/testing/vma: convert bulk of test code to vma_flags_t Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 05/25] mm/vma: use new VMA flags for sticky flags logic Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 06/25] tools/testing/vma: fix VMA flag tests Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 07/25] mm/vma: add append_vma_flags() helper Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 08/25] tools/testing/vma: add simple test for append_vma_flags() Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 09/25] mm: unexport vm_brk_flags() and eliminate vm_flags parameter Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 10/25] mm/vma: introduce vma_flags_same[_mask/_pair]() Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 11/25] mm/vma: introduce [vma_flags,legacy]_to_[legacy,vma_flags]() helpers Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 12/25] tools/testing/vma: test that legacy flag helpers work correctly Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 13/25] mm/vma: introduce vma_test[_any[_mask]](), and make inlining consistent Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 14/25] tools/testing/vma: update VMA flag tests to test vma_test[_any_mask]() Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 15/25] mm: introduce vma_flags_count() and vma[_flags]_test_single_mask() Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 16/25] tools/testing/vma: test vma_flags_count,vma[_flags]_test_single_mask Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 17/25] mm: convert do_brk_flags() to use vma_flags_t Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 18/25] mm: update vma_supports_mlock() to use new VMA flags Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 19/25] mm/vma: introduce vma_clear_flags[_mask]() Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 20/25] tools/testing/vma: update VMA tests to test vma_clear_flags[_mask]() Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 21/25] mm/vma: convert as much as we can in mm/vma.c to vma_flags_t Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 22/25] tools: bitmap: add missing bitmap_copy() implementation Lorenzo Stoakes (Oracle)
2026-03-20 19:38 ` [PATCH v4 23/25] mm/vma: convert vma_modify_flags[_uffd]() to use vma_flags_t Lorenzo Stoakes (Oracle)
2026-03-23 15:47 ` Vlastimil Babka (SUSE)
2026-03-20 19:38 ` [PATCH v4 24/25] mm/vma: convert __mmap_region() " Lorenzo Stoakes (Oracle)
2026-03-23 15:49 ` Vlastimil Babka (SUSE)
2026-03-20 19:38 ` [PATCH v4 25/25] mm: simplify VMA flag tests of excluded flags Lorenzo Stoakes (Oracle)
2026-03-23 15:51 ` Vlastimil Babka (SUSE) [this message]
2026-03-20 19:56 ` [PATCH v4 00/25] mm/vma: convert vm_flags_t to vma_flags_t in vma code Andrew Morton
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