+ mm-io-mapping-precompute-remap-protection-flags-for-clarity.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/io-mapping: precompute remap protection flags for clarity
has been added to the -mm mm-unstable branch.  Its filename is
     mm-io-mapping-precompute-remap-protection-flags-for-clarity.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-io-mapping-precompute-remap-protection-flags-for-clarity.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: Ye Liu <liuye@kylinos.cn>
Subject: mm/io-mapping: precompute remap protection flags for clarity
Date: Sun, 27 Apr 2025 18:04:40 +0800

Patch series "mm: small cleanups for io-mapping, debug_page_alloc and
numa".

This series includes three small cleanups to mm/:

- io-mapping: simplify remap protection flag calculation
- debug_page_alloc: improve error message by printing invalid input
- numa: remove unnecessary variable for clarity

No functional changes.


This patch (of 3):

In io_mapping_map_user(), precompute the page protection flags in a local
variable before calling remap_pfn_range_notrack().

No functional change.

Link: https://lkml.kernel.org/r/20250427100442.958352-1-ye.liu@linux.dev
Link: https://lkml.kernel.org/r/20250427100442.958352-2-ye.liu@linux.dev
Signed-off-by: Ye Liu <liuye@kylinos.cn>
Cc: David Hildenbrand <david@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/io-mapping.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/mm/io-mapping.c~mm-io-mapping-precompute-remap-protection-flags-for-clarity
+++ a/mm/io-mapping.c
@@ -21,9 +21,10 @@ int io_mapping_map_user(struct io_mappin
 	if (WARN_ON_ONCE((vma->vm_flags & expected_flags) != expected_flags))
 		return -EINVAL;
 
+	pgprot_t remap_prot = __pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) |
+				       (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK));
+
 	/* We rely on prevalidation of the io-mapping to skip track_pfn(). */
-	return remap_pfn_range_notrack(vma, addr, pfn, size,
-		__pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) |
-			 (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK)));
+	return remap_pfn_range_notrack(vma, addr, pfn, size, remap_prot);
 }
 EXPORT_SYMBOL_GPL(io_mapping_map_user);
_

Patches currently in -mm which might be from liuye@kylinos.cn are

mm-show_mem-optimize-si_meminfo_node-by-reducing-redundant-code.patch
mm-page_alloc-simplify-free_page_is_bad-by-removing-free_page_is_bad_report.patch
fs-proc-page-refactoring-to-reduce-code-duplication.patch
mm-rmap-rename-page__anon_vma-to-anon_vma-for-consistency.patch
mm-rmap-fix-typo-in-comment-in-page_address_in_vma.patch
mm-io-mapping-precompute-remap-protection-flags-for-clarity.patch
mm-debug_page_alloc-improve-error-message-for-invalid-guardpage-minorder.patch
mm-numa-remove-unnecessary-local-variable-in-alloc_node_data.patch