On 4/22/20 2:14 AM, Michel Lespinasse wrote:
> Define a new initializer for the mmap locking api.
> Initially this just evaluates to __RWSEM_INITIALIZER as the API
> is defined as wrappers around rwsem.
>
> Signed-off-by: Michel Lespinasse <wal...@google.com>
Reviewed-by: Vlastimil Babka <vba...@suse.cz>
Nit below.
> ---
> arch/x86/kernel/tboot.c | 2 +-
> drivers/firmware/efi/efi.c | 2 +-
> include/linux/mmap_lock.h | 3 +++
> mm/init-mm.c | 2 +-
> 4 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
> index b89f6ac6a0c0..885058325c20 100644
> --- a/arch/x86/kernel/tboot.c
> +++ b/arch/x86/kernel/tboot.c
> @@ -90,7 +90,7 @@ static struct mm_struct tboot_mm = {
> .pgd = swapper_pg_dir,
> .mm_users = ATOMIC_INIT(2),
> .mm_count = ATOMIC_INIT(1),
> - .mmap_sem = __RWSEM_INITIALIZER(init_mm.mmap_sem),
> + MMAP_LOCK_INITIALIZER(init_mm)
> .page_table_lock = __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
> .mmlist = LIST_HEAD_INIT(init_mm.mmlist),
> };
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 911a2bd0f6b7..916313ec8acb 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -54,7 +54,7 @@ struct mm_struct efi_mm = {
> .mm_rb = RB_ROOT,
> .mm_users = ATOMIC_INIT(2),
> .mm_count = ATOMIC_INIT(1),
> - .mmap_sem = __RWSEM_INITIALIZER(efi_mm.mmap_sem),
> + MMAP_LOCK_INITIALIZER(efi_mm)
> .page_table_lock = __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
> .mmlist = LIST_HEAD_INIT(efi_mm.mmlist),
> .cpu_bitmap = { [BITS_TO_LONGS(NR_CPUS)] = 0},
> diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h
> index d1826ce42f00..9e104835a0d1 100644
> --- a/include/linux/mmap_lock.h
> +++ b/include/linux/mmap_lock.h
> @@ -1,6 +1,9 @@
> #ifndef _LINUX_MMAP_LOCK_H
> #define _LINUX_MMAP_LOCK_H
>
> +#define MMAP_LOCK_INITIALIZER(name) \
> + .mmap_sem = __RWSEM_INITIALIZER(name.mmap_sem),
"(name).mmap_sem" is safer in a macro?
> +
> static inline void mmap_init_lock(struct mm_struct *mm)
> {
> init_rwsem(&mm->mmap_sem);
> diff --git a/mm/init-mm.c b/mm/init-mm.c
> index 19603302a77f..fe9c03d8e07b 100644
> --- a/mm/init-mm.c
> +++ b/mm/init-mm.c
> @@ -31,7 +31,7 @@ struct mm_struct init_mm = {
> .pgd = swapper_pg_dir,
> .mm_users = ATOMIC_INIT(2),
> .mm_count = ATOMIC_INIT(1),
> - .mmap_sem = __RWSEM_INITIALIZER(init_mm.mmap_sem),
> + MMAP_LOCK_INITIALIZER(init_mm)
> .page_table_lock = __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
> .arg_lock = __SPIN_LOCK_UNLOCKED(init_mm.arg_lock),
> .mmlist = LIST_HEAD_INIT(init_mm.mmlist),
>
