On Wed, May 25, 2022 at 09:09:09AM +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. Currentlyy there are just two callers for check_pfn_span()
Currently
> i.e __add_pages() and __remove_pages(). Let's clean this up.
>
> 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>
One could argue if this is really a cleanup.
I kind of agree that the "reason" thingy is a bit shaky, but instead of having a
single place where we call WARN(), we now do have two.
> ---
> mm/memory_hotplug.c | 19 +++++++++----------
> 1 file changed, 9 insertions(+), 10 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 416b38ca8def..9b3d7295ef93 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 +315,11 @@ 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)
> + err = check_pfn_span(pfn, nr_pages);
> + if (err) {
> + WARN(1, "Misaligned %s start: %#lx end: #%lx\n", __func__, pfn, pfn + nr_pages - 1);
> return err;
> + }
If you want to further clean this up, I would just do
if (check_pfn_span()) {
WARN(....)
return -EINVAL;
}
here as we do in __remove_pages(). check_pfn_span() can either return 0 or -EINVAL,
so I think it is fine.
--
Oscar Salvador
SUSE Labs
