Commit b3dcc9d1 authored by Mike Rapoport (Microsoft)'s avatar Mike Rapoport (Microsoft)
Browse files

memblock: fix kernel-doc for MEMBLOCK_RSRV_NOINIT 



The kernel-doc description of MEMBLOCK_RSRV_NOINIT and
memblock_reserved_mark_noinit() do not accurately describe their
functionality.

Expand their kernel doc to make it clear that the user of
MEMBLOCK_RSRV_NOINIT is responsible to properly initialize the struct pages
for such regions and add more details about effects of using this flag.

Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/f8140a17-c4ec-489b-b314-d45abe48bf36@redhat.com
Link: https://lore.kernel.org/r/20250826071947.1949725-1-rppt@kernel.org


Signed-off-by: default avatarMike Rapoport (Microsoft) <rppt@kernel.org>
parent 4647c4de

include/linux/memblock.h

+3 −2
Original line number Diff line number Diff line
@@ -40,8 +40,9 @@ extern unsigned long long max_possible_pfn; 
 * via a driver, and never indicated in the firmware-provided memory map as

 * system RAM. This corresponds to IORESOURCE_SYSRAM_DRIVER_MANAGED in the

 * kernel resource tree.

 * @MEMBLOCK_RSRV_NOINIT: memory region for which struct pages are

 * not initialized (only for reserved regions).

 * @MEMBLOCK_RSRV_NOINIT: reserved memory region for which struct pages are not

 * fully initialized. Users of this flag are responsible to properly initialize

 * struct pages of this region

 * @MEMBLOCK_RSRV_KERN: memory region that is reserved for kernel use,

 * either explictitly with memblock_reserve_kern() or via memblock

 * allocation APIs. All memblock allocations set this flag.

mm/memblock.c

+11 −4
Original line number Diff line number Diff line
@@ -1091,13 +1091,20 @@ int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size) 


/**

 * memblock_reserved_mark_noinit - Mark a reserved memory region with flag

 * MEMBLOCK_RSRV_NOINIT which results in the struct pages not being initialized

 * for this region.

 * MEMBLOCK_RSRV_NOINIT

 *

 * @base: the base phys addr of the region

 * @size: the size of the region

 *

 * struct pages will not be initialized for reserved memory regions marked with

 * %MEMBLOCK_RSRV_NOINIT.

 * The struct pages for the reserved regions marked %MEMBLOCK_RSRV_NOINIT will

 * not be fully initialized to allow the caller optimize their initialization.

 *

 * When %CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled, setting this flag

 * completely bypasses the initialization of struct pages for such region.

 *

 * When %CONFIG_DEFERRED_STRUCT_PAGE_INIT is disabled, struct pages in this

 * region will be initialized with default values but won't be marked as

 * reserved.

 *

 * Return: 0 on success, -errno on failure.

 */