[PATCH 5/5] mm: rename leftover i_mmap_mutex

From: Davidlohr Bueso
Date: Mon Jun 24 2013 - 20:22:25 EST

Update the lock to i_mmap_rwsem throughout the kernel.
All changes are in comments and documentation.

Signed-off-by: Davidlohr Bueso <davidlohr.bueso@xxxxxx>
---
Documentation/lockstat.txt | 2 +-
Documentation/vm/locking | 2 +-
arch/x86/mm/hugetlbpage.c | 2 +-
include/linux/mmu_notifier.h | 2 +-
kernel/events/uprobes.c | 2 +-
mm/filemap.c | 10 +++++-----
mm/hugetlb.c | 8 ++++----
mm/mmap.c | 6 +++---
mm/mremap.c | 2 +-
mm/rmap.c | 8 ++++----
10 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/Documentation/lockstat.txt b/Documentation/lockstat.txt
index dd2f7b2..96b8233 100644
--- a/Documentation/lockstat.txt
+++ b/Documentation/lockstat.txt
@@ -168,7 +168,7 @@ View the top contending locks:
dcache_lock: 1037 1161 0.38 45.32 774.51 6611 243371 0.15 306.48 77387.24
&inode->i_mutex: 161 286 18446744073709 62882.54 1244614.55 3653 20598 18446744073709 62318.60 1693822.74
&zone->lru_lock: 94 94 0.53 7.33 92.10 4366 32690 0.29 59.81 16350.06
- &inode->i_data.i_mmap_mutex: 79 79 0.40 3.77 53.03 11779 87755 0.28 116.93 29898.44
+ &inode->i_data.i_mmap_rwsem: 79 79 0.40 3.77 53.03 11779 87755 0.28 116.93 29898.44
&q->__queue_lock: 48 50 0.52 31.62 86.31 774 13131 0.17 113.08 12277.52
&rq->rq_lock_key: 43 47 0.74 68.50 170.63 3706 33929 0.22 107.99 17460.62
&rq->rq_lock_key#2: 39 46 0.75 6.68 49.03 2979 32292 0.17 125.17 17137.63
diff --git a/Documentation/vm/locking b/Documentation/vm/locking
index f61228b..fb64028 100644
--- a/Documentation/vm/locking
+++ b/Documentation/vm/locking
@@ -66,7 +66,7 @@ in some cases it is not really needed. Eg, vm_start is modified by
expand_stack(), it is hard to come up with a destructive scenario without
having the vmlist protection in this case.

-The page_table_lock nests with the inode i_mmap_mutex and the kmem cache
+The page_table_lock nests with the inode i_mmap_rwsem and the kmem cache
c_spinlock spinlocks. This is okay, since the kmem code asks for pages after
dropping c_spinlock. The page_table_lock also nests with pagecache_lock and
pagemap_lru_lock spinlocks, and no code asks for memory with these locks
diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
index 9c61a1e..df68d13 100644
--- a/arch/x86/mm/hugetlbpage.c
+++ b/arch/x86/mm/hugetlbpage.c
@@ -60,7 +60,7 @@ static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
* and returns the corresponding pte. While this is not necessary for the
* !shared pmd case because we can allocate the pmd later as well, it makes the
* code much cleaner. pmd allocation is essential for the shared case because
- * pud has to be populated inside the same i_mmap_mutex section - otherwise
+ * pud has to be populated inside the same i_mmap_rwsem section - otherwise
* racing tasks could either miss the sharing (see huge_pte_offset) or select a
* bad pmd for sharing.
*/
diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
index deca874..f9c11ab 100644
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -151,7 +151,7 @@ struct mmu_notifier_ops {
* Therefore notifier chains can only be traversed when either
*
* 1. mmap_sem is held.
- * 2. One of the reverse map locks is held (i_mmap_mutex or anon_vma->rwsem).
+ * 2. One of the reverse map locks is held (i_mmap_rwsem or anon_vma->rwsem).
* 3. No other concurrent thread can access the list (release)
*/
struct mmu_notifier {
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index c7b9f45..4ca146e 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -700,7 +700,7 @@ build_map_info(struct address_space *mapping, loff_t offset, bool is_register)

if (!prev && !more) {
/*
- * Needs GFP_NOWAIT to avoid i_mmap_mutex recursion through
+ * Needs GFP_NOWAIT to avoid i_mmap_rwsem recursion through
* reclaim. This is optimistic, no harm done if it fails.
*/
prev = kmalloc(sizeof(struct map_info),
diff --git a/mm/filemap.c b/mm/filemap.c
index 7905fe7..5d3ae93 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -60,16 +60,16 @@
/*
* Lock ordering:
*
- * ->i_mmap_mutex (truncate_pagecache)
+ * ->i_mmap_rwsem (truncate_pagecache)
* ->private_lock (__free_pte->__set_page_dirty_buffers)
* ->swap_lock (exclusive_swap_page, others)
* ->mapping->tree_lock
*
* ->i_mutex
- * ->i_mmap_mutex (truncate->unmap_mapping_range)
+ * ->i_mmap_rwsem (truncate->unmap_mapping_range)
*
* ->mmap_sem
- * ->i_mmap_mutex
+ * ->i_mmap_rwsem
* ->page_table_lock or pte_lock (various, mainly in memory.c)
* ->mapping->tree_lock (arch-dependent flush_dcache_mmap_lock)
*
@@ -83,7 +83,7 @@
* sb_lock (fs/fs-writeback.c)
* ->mapping->tree_lock (__sync_single_inode)
*
- * ->i_mmap_mutex
+ * ->i_mmap_rwsem
* ->anon_vma.lock (vma_adjust)
*
* ->anon_vma.lock
@@ -103,7 +103,7 @@
* ->inode->i_lock (zap_pte_range->set_page_dirty)
* ->private_lock (zap_pte_range->__set_page_dirty_buffers)
*
- * ->i_mmap_mutex
+ * ->i_mmap_rwsem
* ->tasklist_lock (memory_failure, collect_procs_ao)
*/

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 1becd0a..041f58f 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2458,9 +2458,9 @@ void __unmap_hugepage_range_final(struct mmu_gather *tlb,
* on its way out. We're lucky that the flag has such an appropriate
* name, and can in fact be safely cleared here. We could clear it
* before the __unmap_hugepage_range above, but all that's necessary
- * is to clear it before releasing the i_mmap_mutex. This works
+ * is to clear it before releasing the i_mmap_rwsem. This works
* because in the context this is called, the VMA is about to be
- * destroyed and the i_mmap_mutex is held.
+ * destroyed and the i_mmap_rwsem is held.
*/
vma->vm_flags &= ~VM_MAYSHARE;
}
@@ -3067,9 +3067,9 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
}
spin_unlock(&mm->page_table_lock);
/*
- * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
+ * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
* may have cleared our pud entry and done put_page on the page table:
- * once we release i_mmap_mutex, another task can do the final put_page
+ * once we release i_mmap_rwsem, another task can do the final put_page
* and that page table be reused and filled with junk.
*/
flush_tlb_range(vma, start, end);
diff --git a/mm/mmap.c b/mm/mmap.c
index b4e142a..b4ca52a 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -205,7 +205,7 @@ error:
}

/*
- * Requires inode->i_mapping->i_mmap_mutex
+ * Requires inode->i_mapping->i_mmap_rwsem
*/
static void __remove_shared_vm_struct(struct vm_area_struct *vma,
struct file *file, struct address_space *mapping)
@@ -2759,7 +2759,7 @@ void exit_mmap(struct mm_struct *mm)

/* Insert vm structure into process list sorted by address
* and into the inode's i_mmap tree. If vm_file is non-NULL
- * then i_mmap_mutex is taken here.
+ * then i_mmap_rwsem is taken here.
*/
int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
{
@@ -3043,7 +3043,7 @@ static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
* vma in this mm is backed by the same anon_vma or address_space.
*
* We can take all the locks in random order because the VM code
- * taking i_mmap_mutex or anon_vma->rwsem outside the mmap_sem never
+ * taking i_mmap_rwsem or anon_vma->rwsem outside the mmap_sem never
* takes more than one of them in a row. Secondly we're protected
* against a concurrent mm_take_all_locks() by the mm_all_locks_mutex.
*
diff --git a/mm/mremap.c b/mm/mremap.c
index 02fc5df..742fe28 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -81,7 +81,7 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
spinlock_t *old_ptl, *new_ptl;

/*
- * When need_rmap_locks is true, we take the i_mmap_mutex and anon_vma
+ * When need_rmap_locks is true, we take the i_mmap_rwsem and anon_vma
* locks to ensure that rmap will always observe either the old or the
* new ptes. This is the easiest way to avoid races with
* truncate_pagecache(), page migration, etc...
diff --git a/mm/rmap.c b/mm/rmap.c
index 98b986d..1bfde51 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -23,7 +23,7 @@
* inode->i_mutex (while writing or truncating, not reading or faulting)
* mm->mmap_sem
* page->flags PG_locked (lock_page)
- * mapping->i_mmap_mutex
+ * mapping->i_mmap_rwsem
* anon_vma->rwsem
* mm->page_table_lock or pte_lock
* zone->lru_lock (in mark_page_accessed, isolate_lru_page)
@@ -804,14 +804,14 @@ static int page_referenced_file(struct page *page,
* The page lock not only makes sure that page->mapping cannot
* suddenly be NULLified by truncation, it makes sure that the
* structure at mapping cannot be freed and reused yet,
- * so we can safely take mapping->i_mmap_mutex.
+ * so we can safely take mapping->i_mmap_rwsem.
*/
BUG_ON(!PageLocked(page));

i_mmap_lock_read(mapping);

/*
- * i_mmap_mutex does not stabilize mapcount at all, but mapcount
+ * i_mmap_rwsem does not stabilize mapcount at all, but mapcount
* is more likely to be accurate if we note it after spinning.
*/
mapcount = page_mapcount(page);
@@ -1291,7 +1291,7 @@ out_mlock:
/*
* We need mmap_sem locking, Otherwise VM_LOCKED check makes
* unstable result and race. Plus, We can't wait here because
- * we now hold anon_vma->rwsem or mapping->i_mmap_mutex.
+ * we now hold anon_vma->rwsem or mapping->i_mmap_rwsem.
* if trylock failed, the page remain in evictable lru and later
* vmscan could retry to move the page to unevictable lru if the
* page is actually mlocked.
--
1.7.11.7

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