mm/memory_hotplug: fix memmap_on_memory sysfs value retrieval

commit 1168413414 upstream.

set_memmap_mode() stores the kernel parameter memmap mode as an integer.
However, the get_memmap_mode() function utilizes param_get_bool() to fetch
the value as a boolean, leading to potential endianness issue.  On
Big-endian architectures, the memmap_on_memory is consistently displayed
as 'N' regardless of its actual status.

To address this endianness problem, the solution involves obtaining the
mode as an integer.  This adjustment ensures the proper display of the
memmap_on_memory parameter, presenting it as one of the following options:
Force, Y, or N.

Link: https://lkml.kernel.org/r/20240110140127.241451-1-sumanthk@linux.ibm.com
Fixes: 2d1f649c7c ("mm/memory_hotplug: support memmap_on_memory when memmap is not aligned to pageblocks")
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Suggested-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: <stable@vger.kernel.org>	[6.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sumanth Korikkar 2024-01-10 15:01:27 +01:00 committed by Greg Kroah-Hartman
parent f7f4ff54c4
commit 0f91df0c0f
1 changed files with 5 additions and 3 deletions

View File

@ -101,9 +101,11 @@ static int set_memmap_mode(const char *val, const struct kernel_param *kp)
static int get_memmap_mode(char *buffer, const struct kernel_param *kp)
{
if (*((int *)kp->arg) == MEMMAP_ON_MEMORY_FORCE)
return sprintf(buffer, "force\n");
return param_get_bool(buffer, kp);
int mode = *((int *)kp->arg);
if (mode == MEMMAP_ON_MEMORY_FORCE)
return sprintf(buffer, "force\n");
return sprintf(buffer, "%c\n", mode ? 'Y' : 'N');
}
static const struct kernel_param_ops memmap_mode_ops = {