The patch titled
Subject: mmap locking API: convert nested write lock sites
has been added to the -mm tree. Its filename is
mmap-locking-api-convert-nested-write-lock-sites.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mmap-locking-api-convert-nested-write-lock-sites.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mmap-locking-api-convert-nested-write-lock-sites.patch
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------------------------------------------------------
From: Michel Lespinasse <walken@xxxxxxxxxx>
Subject: mmap locking API: convert nested write lock sites
Add API for nested write locks and convert the few call sites doing that.
Link: http://lkml.kernel.org/r/20200520052908.204642-7-walken@xxxxxxxxxx
Signed-off-by: Michel Lespinasse <walken@xxxxxxxxxx>
Reviewed-by: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
Reviewed-by: Laurent Dufour <ldufour@xxxxxxxxxxxxx>
Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Davidlohr Bueso <dbueso@xxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Liam Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ying Han <yinghan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/um/include/asm/mmu_context.h | 3 ++-
include/linux/mmap_lock.h | 5 +++++
kernel/fork.c | 2 +-
3 files changed, 8 insertions(+), 2 deletions(-)
--- a/arch/um/include/asm/mmu_context.h~mmap-locking-api-convert-nested-write-lock-sites
+++ a/arch/um/include/asm/mmu_context.h
@@ -8,6 +8,7 @@
#include <linux/sched.h>
#include <linux/mm_types.h>
+#include <linux/mmap_lock.h>
#include <asm/mmu.h>
@@ -47,7 +48,7 @@ static inline void activate_mm(struct mm
* when the new ->mm is used for the first time.
*/
__switch_mm(&new->context.id);
- down_write_nested(&new->mmap_sem, 1);
+ mmap_write_lock_nested(new, SINGLE_DEPTH_NESTING);
uml_setup_stubs(new);
mmap_write_unlock(new);
}
--- a/include/linux/mmap_lock.h~mmap-locking-api-convert-nested-write-lock-sites
+++ a/include/linux/mmap_lock.h
@@ -11,6 +11,11 @@ static inline void mmap_write_lock(struc
down_write(&mm->mmap_sem);
}
+static inline void mmap_write_lock_nested(struct mm_struct *mm, int subclass)
+{
+ down_write_nested(&mm->mmap_sem, subclass);
+}
+
static inline int mmap_write_lock_killable(struct mm_struct *mm)
{
return down_write_killable(&mm->mmap_sem);
--- a/kernel/fork.c~mmap-locking-api-convert-nested-write-lock-sites
+++ a/kernel/fork.c
@@ -504,7 +504,7 @@ static __latent_entropy int dup_mmap(str
/*
* Not linked in yet - no deadlock potential:
*/
- down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING);
+ mmap_write_lock_nested(mm, SINGLE_DEPTH_NESTING);
/* No ordering required: file already has been exposed. */
RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm));
_
Patches currently in -mm which might be from walken@xxxxxxxxxx are
mmap-locking-api-initial-implementation-as-rwsem-wrappers.patch
mmu-notifier-use-the-new-mmap-locking-api.patch
dma-reservations-use-the-new-mmap-locking-api.patch
mmap-locking-api-use-coccinelle-to-convert-mmap_sem-rwsem-call-sites.patch
mmap-locking-api-convert-mmap_sem-call-sites-missed-by-coccinelle.patch
mmap-locking-api-convert-nested-write-lock-sites.patch
mmap-locking-api-add-mmap_read_trylock_non_owner.patch
mmap-locking-api-add-mmap_lock_initializer.patch
mmap-locking-api-add-mmap_assert_locked-and-mmap_assert_write_locked.patch
mmap-locking-api-rename-mmap_sem-to-mmap_lock.patch
mmap-locking-api-convert-mmap_sem-api-comments.patch
mmap-locking-api-convert-mmap_sem-comments.patch
