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Date: Sat, 8 Jun 2024 00:51:44 +0000
From: Wei Yang <richard.weiyang@gmail.com>
To: David Hildenbrand <david@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Wei Yang <richard.weiyang@gmail.com>
Subject: Re: [PATCH v1 2/2] mm/highmem: make nr_free_highpages() return
 "unsigned long"
Message-ID: <20240608005144.ypbq4442bh46tmqb@master>
Reply-To: Wei Yang <richard.weiyang@gmail.com>
References: <20240607083711.62833-1-david@redhat.com>
 <20240607083711.62833-3-david@redhat.com>
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On Fri, Jun 07, 2024 at 10:37:11AM +0200, David Hildenbrand wrote:
>It looks rather weird that totalhigh_pages() returns an
>"unsigned long" but nr_free_highpages() returns an "unsigned int".
>
>Let's return an "unsigned long" from nr_free_highpages() to be
>consistent.
>
>While at it, use a plain "0" instead of a "0UL" in the !CONFIG_HIGHMEM
>totalhigh_pages() implementation, to make these look alike as well.

I am not sure why not use 0UL for both?

>
>Signed-off-by: David Hildenbrand <david@redhat.com>
>---
> include/linux/highmem-internal.h | 8 ++++----
> include/linux/highmem.h          | 2 +-
> mm/highmem.c                     | 4 ++--
> 3 files changed, 7 insertions(+), 7 deletions(-)
>
>diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h
>index 65f865fbbac04..dd100e849f5e0 100644
>--- a/include/linux/highmem-internal.h
>+++ b/include/linux/highmem-internal.h
>@@ -131,10 +131,10 @@ static inline void __kunmap_atomic(const void *addr)
> 		preempt_enable();
> }
> 
>-unsigned int __nr_free_highpages(void);
>+unsigned long __nr_free_highpages(void);
> unsigned long __totalhigh_pages(void);
> 
>-static inline unsigned int nr_free_highpages(void)
>+static inline unsigned long nr_free_highpages(void)
> {
> 	return __nr_free_highpages();
> }
>@@ -234,8 +234,8 @@ static inline void __kunmap_atomic(const void *addr)
> 		preempt_enable();
> }
> 
>-static inline unsigned int nr_free_highpages(void) { return 0; }
>-static inline unsigned long totalhigh_pages(void) { return 0UL; }
>+static inline unsigned long nr_free_highpages(void) { return 0; }
>+static inline unsigned long totalhigh_pages(void) { return 0; }
> 
> static inline bool is_kmap_addr(const void *x)
> {
>diff --git a/include/linux/highmem.h b/include/linux/highmem.h
>index 6b0d6f3c8580c..930a591b9b616 100644
>--- a/include/linux/highmem.h
>+++ b/include/linux/highmem.h
>@@ -179,7 +179,7 @@ static inline void *kmap_local_folio(struct folio *folio, size_t offset);
> static inline void *kmap_atomic(struct page *page);
> 
> /* Highmem related interfaces for management code */
>-static inline unsigned int nr_free_highpages(void);
>+static inline unsigned long nr_free_highpages(void);
> static inline unsigned long totalhigh_pages(void);
> 
> #ifndef ARCH_HAS_FLUSH_ANON_PAGE
>diff --git a/mm/highmem.c b/mm/highmem.c
>index 3c4e9f8c26dcd..1ece1e69031e7 100644
>--- a/mm/highmem.c
>+++ b/mm/highmem.c
>@@ -111,10 +111,10 @@ static inline wait_queue_head_t *get_pkmap_wait_queue_head(unsigned int color)
> }
> #endif
> 
>-unsigned int __nr_free_highpages(void)
>+unsigned long __nr_free_highpages(void)
> {
>+	unsigned long pages = 0;
> 	struct zone *zone;
>-	unsigned int pages = 0;
> 
> 	for_each_populated_zone(zone) {
> 		if (is_highmem(zone))
>-- 
>2.45.1

-- 
Wei Yang
Help you, Help me