Re: [PATCH V2] mm/memory_hotplug: Drop 'reason' argument from check_pfn_span()

From: Oscar Salvador
Date: Mon May 30 2022 - 01:04:07 EST


On Thu, May 26, 2022 at 07:42:58AM +0530, Anshuman Khandual wrote:
> In check_pfn_span(), a 'reason' string is being used to recreate the caller
> function name, while printing the warning message. It is really unnecessary
> as the warning message could just be printed inside the caller depending on
> the return code. Currently there are just two callers for check_pfn_span()
> i.e __add_pages() and __remove_pages(). Let's clean this up.
>
> Cc: Oscar Salvador <osalvador@xxxxxxx>
> Cc: David Hildenbrand <david@xxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: linux-mm@xxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>

Acked-by: Oscar Salvador <osalvador@xxxxxxx>

> ---
> Changes in V2:
>
> - Fixed typo in commit message
> - Dropped using 'ret' to capture check_pfn_span() return value in __add_pages()
>
> Changes in V1:
>
> https://lore.kernel.org/all/20220525033910.3781764-1-anshuman.khandual@xxxxxxx/
>
> mm/memory_hotplug.c | 20 +++++++++-----------
> 1 file changed, 9 insertions(+), 11 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 416b38ca8def..3b24386e9276 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -220,8 +220,7 @@ static void release_memory_resource(struct resource *res)
> kfree(res);
> }
>
> -static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
> - const char *reason)
> +static int check_pfn_span(unsigned long pfn, unsigned long nr_pages)
> {
> /*
> * Disallow all operations smaller than a sub-section and only
> @@ -238,12 +237,8 @@ static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
> min_align = PAGES_PER_SUBSECTION;
> else
> min_align = PAGES_PER_SECTION;
> - if (!IS_ALIGNED(pfn, min_align)
> - || !IS_ALIGNED(nr_pages, min_align)) {
> - WARN(1, "Misaligned __%s_pages start: %#lx end: #%lx\n",
> - reason, pfn, pfn + nr_pages - 1);
> + if (!IS_ALIGNED(pfn, min_align) || !IS_ALIGNED(nr_pages, min_align))
> return -EINVAL;
> - }
> return 0;
> }
>
> @@ -320,9 +315,10 @@ int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
> altmap->alloc = 0;
> }
>
> - err = check_pfn_span(pfn, nr_pages, "add");
> - if (err)
> - return err;
> + if (check_pfn_span(pfn, nr_pages)) {
> + WARN(1, "Misaligned %s start: %#lx end: #%lx\n", __func__, pfn, pfn + nr_pages - 1);
> + return -EINVAL;
> + }
>
> for (; pfn < end_pfn; pfn += cur_nr_pages) {
> /* Select all remaining pages up to the next section boundary */
> @@ -518,8 +514,10 @@ void __remove_pages(unsigned long pfn, unsigned long nr_pages,
>
> map_offset = vmem_altmap_offset(altmap);
>
> - if (check_pfn_span(pfn, nr_pages, "remove"))
> + if (check_pfn_span(pfn, nr_pages)) {
> + WARN(1, "Misaligned %s start: %#lx end: #%lx\n", __func__, pfn, pfn + nr_pages - 1);
> return;
> + }
>
> for (; pfn < end_pfn; pfn += cur_nr_pages) {
> cond_resched();
> --
> 2.20.1
>

--
Oscar Salvador
SUSE Labs