| Message ID | 20200326070236.235835-8-walken@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add a new mmap locking API wrapping mmap_sem calls | expand |
Le 26/03/2020 à 08:02, Michel Lespinasse a écrit : > 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. I can't see the benefit of this change. The overall idea is to hide the mmap_sem name. Here the macro MMAP_LOCK_INITIALIZER() doesn't hide the name. I think we can keep that in place until the real change of the mmap_sem to something else. Cheers, Laurent. > > Signed-off-by: Michel Lespinasse <walken@google.com> > --- > arch/x86/kernel/tboot.c | 2 +- > drivers/firmware/efi/efi.c | 2 +- > include/linux/mmap_lock.h | 2 ++ > mm/init-mm.c | 2 +- > 4 files changed, 5 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c > index b89f6ac6a0c0..4b79335624b1 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_sem = MMAP_LOCK_INITIALIZER(init_mm.mmap_sem), > .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 21ea99f65113..5bdfe698cd7f 100644 > --- a/drivers/firmware/efi/efi.c > +++ b/drivers/firmware/efi/efi.c > @@ -60,7 +60,7 @@ 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_sem = MMAP_LOCK_INITIALIZER(efi_mm.mmap_sem), > .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 00d6cc02581d..7474b15bba38 100644 > --- a/include/linux/mmap_lock.h > +++ b/include/linux/mmap_lock.h > @@ -1,6 +1,8 @@ > #ifndef _LINUX_MMAP_LOCK_H > #define _LINUX_MMAP_LOCK_H > > +#define MMAP_LOCK_INITIALIZER(name) __RWSEM_INITIALIZER(name) > + > 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..3c128bd6a30c 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_sem = MMAP_LOCK_INITIALIZER(init_mm.mmap_sem), > .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), >
On Mon, Apr 6, 2020 at 2:46 AM Laurent Dufour <ldufour@linux.ibm.com> wrote: > > Le 26/03/2020 à 08:02, Michel Lespinasse a écrit : > > 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. > > I can't see the benefit of this change. > The overall idea is to hide the mmap_sem name. Here the macro > MMAP_LOCK_INITIALIZER() doesn't hide the name. The idea for the initializer is that it makes it easier to change the underlying implementation - if we do, we can change the initializer without having to change every place where it is used. I actually do that in my other patch series converting the mmap_sem to a range lock. But you are correct that it does not help with renaming the mmap_sem field - my next commit in this series still has to do that in every place this initializer is used.
diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c index b89f6ac6a0c0..4b79335624b1 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_sem = MMAP_LOCK_INITIALIZER(init_mm.mmap_sem), .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 21ea99f65113..5bdfe698cd7f 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -60,7 +60,7 @@ 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_sem = MMAP_LOCK_INITIALIZER(efi_mm.mmap_sem), .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 00d6cc02581d..7474b15bba38 100644 --- a/include/linux/mmap_lock.h +++ b/include/linux/mmap_lock.h @@ -1,6 +1,8 @@ #ifndef _LINUX_MMAP_LOCK_H #define _LINUX_MMAP_LOCK_H +#define MMAP_LOCK_INITIALIZER(name) __RWSEM_INITIALIZER(name) + 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..3c128bd6a30c 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_sem = MMAP_LOCK_INITIALIZER(init_mm.mmap_sem), .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),
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 <walken@google.com> --- arch/x86/kernel/tboot.c | 2 +- drivers/firmware/efi/efi.c | 2 +- include/linux/mmap_lock.h | 2 ++ mm/init-mm.c | 2 +- 4 files changed, 5 insertions(+), 3 deletions(-)