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Date:   Tue, 14 Apr 2020 17:43:51 -0700
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Subject: [PATCH v4 08/10] mmap locking API: add MMAP_LOCK_INITIALIZER
From:   Michel Lespinasse <walken@google.com>
To:     Andrew Morton <akpm@linux-foundation.org>,
        linux-mm <linux-mm@kvack.org>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Laurent Dufour <ldufour@linux.ibm.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Matthew Wilcox <willy@infradead.org>,
        Liam Howlett <Liam.Howlett@oracle.com>,
        Jerome Glisse <jglisse@redhat.com>,
        Davidlohr Bueso <dave@stgolabs.net>,
        David Rientjes <rientjes@google.com>,
        Hugh Dickins <hughd@google.com>, Ying Han <yinghan@google.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Daniel Jordan <daniel.m.jordan@oracle.com>,
        Michel Lespinasse <walken@google.com>
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Sender: linux-kernel-owner@vger.kernel.org
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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(-)

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 911a2bd0f6b7..4bac9d7a48a6 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_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 1050257361aa..07efa379664a 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),
-- 
2.26.0.110.g2183baf09c-goog