In lure of the sleepable-vs-non-sleepable anon-vma/i_mmap locking
discussion, this patchset encapsulates the i_mmap_mutex lock into
two functions to lock and unlock (for writting). This is very similar
to how we currently deal with anon-vma lock, making it a lot easier to
change the lock type.
I've split these changes in to two patches since it makes patch 2 nicer
to review, matching additions with deletions.
Thanks!
Davidlohr Bueso (2):
mm,fs: introduce helpers around i_mmap_mutex
fs,mm: use new helper functions around the i_mmap_mutex
fs/hugetlbfs/inode.c | 4 ++--
include/linux/fs.h | 10 ++++++++++
kernel/events/uprobes.c | 4 ++--
kernel/fork.c | 4 ++--
mm/filemap_xip.c | 4 ++--
mm/fremap.c | 4 ++--
mm/hugetlb.c | 12 ++++++------
mm/memory-failure.c | 4 ++--
mm/memory.c | 8 ++++----
mm/mmap.c | 14 +++++++-------
mm/mremap.c | 4 ++--
mm/nommu.c | 14 +++++++-------
mm/rmap.c | 16 ++++++++--------
13 files changed, 56 insertions(+), 46 deletions(-)
--
1.8.1.4
Various parts of the kernel acquire and release this mutex,
so add i_mmap_lock_write() and immap_unlock_write() helper
functions that will encapsulate this logic. The next patch
will make use of these.
Signed-off-by: Davidlohr Bueso <[email protected]>
---
include/linux/fs.h | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3f40547..b32e64f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -478,6 +478,16 @@ struct block_device {
int mapping_tagged(struct address_space *mapping, int tag);
+static inline void i_mmap_lock_write(struct address_space *mapping)
+{
+ mutex_lock(&mapping->i_mmap_mutex);
+}
+
+static inline void i_mmap_unlock_write(struct address_space *mapping)
+{
+ mutex_unlock(&mapping->i_mmap_mutex);
+}
+
/*
* Might pages of this file be mapped into userspace?
*/
--
1.8.1.4
Convert all open coded mutex_lock/unlock calls to the
i_mmap_[lock/unlock]_write() helpers.
Signed-off-by: Davidlohr Bueso <[email protected]>
---
fs/hugetlbfs/inode.c | 4 ++--
kernel/events/uprobes.c | 4 ++--
kernel/fork.c | 4 ++--
mm/filemap_xip.c | 4 ++--
mm/fremap.c | 4 ++--
mm/hugetlb.c | 12 ++++++------
mm/memory-failure.c | 4 ++--
mm/memory.c | 8 ++++----
mm/mmap.c | 14 +++++++-------
mm/mremap.c | 4 ++--
mm/nommu.c | 14 +++++++-------
mm/rmap.c | 16 ++++++++--------
12 files changed, 46 insertions(+), 46 deletions(-)
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index d19b30a..526319f 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -404,10 +404,10 @@ static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
pgoff = offset >> PAGE_SHIFT;
i_size_write(inode, offset);
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
if (!RB_EMPTY_ROOT(&mapping->i_mmap))
hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
truncate_hugepages(inode, offset);
return 0;
}
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index ad8e1bd..96dd9dc 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -693,7 +693,7 @@ build_map_info(struct address_space *mapping, loff_t offset, bool is_register)
int more = 0;
again:
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
if (!valid_vma(vma, is_register))
continue;
@@ -724,8 +724,8 @@ build_map_info(struct address_space *mapping, loff_t offset, bool is_register)
info->mm = vma->vm_mm;
info->vaddr = offset_to_vaddr(vma, offset);
}
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
if (!more)
goto out;
diff --git a/kernel/fork.c b/kernel/fork.c
index 086fe73..36971d7 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -415,7 +415,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
get_file(file);
if (tmp->vm_flags & VM_DENYWRITE)
atomic_dec(&inode->i_writecount);
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
if (tmp->vm_flags & VM_SHARED)
mapping->i_mmap_writable++;
flush_dcache_mmap_lock(mapping);
@@ -427,7 +427,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
vma_interval_tree_insert_after(tmp, mpnt,
&mapping->i_mmap);
flush_dcache_mmap_unlock(mapping);
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
}
/*
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index 28fe26b..c851586 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -182,7 +182,7 @@ __xip_unmap (struct address_space * mapping,
return;
retry:
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
mm = vma->vm_mm;
address = vma->vm_start +
@@ -202,7 +202,7 @@ retry:
page_cache_release(page);
}
}
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
if (locked) {
mutex_unlock(&xip_sparse_mutex);
diff --git a/mm/fremap.c b/mm/fremap.c
index 5bff081..7d28bcf 100644
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -220,13 +220,13 @@ get_write_lock:
}
goto out;
}
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
flush_dcache_mmap_lock(mapping);
vma->vm_flags |= VM_NONLINEAR;
vma_interval_tree_remove(vma, &mapping->i_mmap);
vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
flush_dcache_mmap_unlock(mapping);
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
}
if (vma->vm_flags & VM_LOCKED) {
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index b49579c..22a673d 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2568,7 +2568,7 @@ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
* this mapping should be shared between all the VMAs,
* __unmap_hugepage_range() is called as the lock is already held
*/
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
/* Do not unmap the current VMA */
if (iter_vma == vma)
@@ -2585,7 +2585,7 @@ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
unmap_hugepage_range(iter_vma, address,
address + huge_page_size(h), page);
}
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
return 1;
}
@@ -3102,7 +3102,7 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
BUG_ON(address >= end);
flush_cache_range(vma, address, end);
- mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
+ i_mmap_lock_write(vma->vm_file->f_mapping);
spin_lock(&mm->page_table_lock);
for (; address < end; address += huge_page_size(h)) {
ptep = huge_pte_offset(mm, address);
@@ -3128,7 +3128,7 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
* and that page table be reused and filled with junk.
*/
flush_tlb_range(vma, start, end);
- mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
+ i_mmap_unlock_write(vma->vm_file->f_mapping);
return pages << h->order;
}
@@ -3287,7 +3287,7 @@ pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
if (!vma_shareable(vma, addr))
return (pte_t *)pmd_alloc(mm, pud, addr);
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
if (svma == vma)
continue;
@@ -3314,7 +3314,7 @@ pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
spin_unlock(&mm->page_table_lock);
out:
pte = (pte_t *)pmd_alloc(mm, pud, addr);
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
return pte;
}
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index bf3351b..7ba8819 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -438,7 +438,7 @@ static void collect_procs_file(struct page *page, struct list_head *to_kill,
struct task_struct *tsk;
struct address_space *mapping = page->mapping;
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
read_lock(&tasklist_lock);
for_each_process(tsk) {
pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
@@ -460,7 +460,7 @@ static void collect_procs_file(struct page *page, struct list_head *to_kill,
}
}
read_unlock(&tasklist_lock);
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
}
/*
diff --git a/mm/memory.c b/mm/memory.c
index ca00039..9f54a90 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1326,9 +1326,9 @@ static void unmap_single_vma(struct mmu_gather *tlb,
* safe to do nothing in this case.
*/
if (vma->vm_file) {
- mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
+ i_mmap_lock_write(vma->vm_file->f_mapping);
__unmap_hugepage_range_final(tlb, vma, start, end, NULL);
- mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
+ i_mmap_unlock_write(vma->vm_file->f_mapping);
}
} else
unmap_page_range(tlb, vma, start, end, details);
@@ -2973,12 +2973,12 @@ void unmap_mapping_range(struct address_space *mapping,
details.last_index = ULONG_MAX;
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap)))
unmap_mapping_range_tree(&mapping->i_mmap, &details);
if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
}
EXPORT_SYMBOL(unmap_mapping_range);
diff --git a/mm/mmap.c b/mm/mmap.c
index 9d54851..e727a3a 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -233,9 +233,9 @@ void unlink_file_vma(struct vm_area_struct *vma)
if (file) {
struct address_space *mapping = file->f_mapping;
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
__remove_shared_vm_struct(vma, file, mapping);
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
}
}
@@ -644,13 +644,13 @@ static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
mapping = vma->vm_file->f_mapping;
if (mapping)
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
__vma_link(mm, vma, prev, rb_link, rb_parent);
__vma_link_file(vma);
if (mapping)
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
mm->map_count++;
validate_mm(mm);
@@ -761,7 +761,7 @@ again: remove_next = 1 + (end > next->vm_end);
next->vm_end);
}
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
if (insert) {
/*
* Put into interval tree now, so instantiated pages
@@ -848,7 +848,7 @@ again: remove_next = 1 + (end > next->vm_end);
anon_vma_unlock_write(anon_vma);
}
if (mapping)
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
if (root) {
uprobe_mmap(vma);
@@ -3081,7 +3081,7 @@ static void vm_unlock_mapping(struct address_space *mapping)
* AS_MM_ALL_LOCKS can't change to 0 from under us
* because we hold the mm_all_locks_mutex.
*/
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
if (!test_and_clear_bit(AS_MM_ALL_LOCKS,
&mapping->flags))
BUG();
diff --git a/mm/mremap.c b/mm/mremap.c
index 91b13d6..e8de648 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -122,7 +122,7 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
if (need_rmap_locks) {
if (vma->vm_file) {
mapping = vma->vm_file->f_mapping;
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
}
if (vma->anon_vma) {
anon_vma = vma->anon_vma;
@@ -159,7 +159,7 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
if (anon_vma)
anon_vma_unlock_write(anon_vma);
if (mapping)
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
}
#define LATENCY_LIMIT (64 * PAGE_SIZE)
diff --git a/mm/nommu.c b/mm/nommu.c
index ecd1f15..28361cf 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -716,11 +716,11 @@ static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
if (vma->vm_file) {
mapping = vma->vm_file->f_mapping;
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
flush_dcache_mmap_lock(mapping);
vma_interval_tree_insert(vma, &mapping->i_mmap);
flush_dcache_mmap_unlock(mapping);
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
}
/* add the VMA to the tree */
@@ -782,11 +782,11 @@ static void delete_vma_from_mm(struct vm_area_struct *vma)
if (vma->vm_file) {
mapping = vma->vm_file->f_mapping;
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
flush_dcache_mmap_lock(mapping);
vma_interval_tree_remove(vma, &mapping->i_mmap);
flush_dcache_mmap_unlock(mapping);
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
}
/* remove from the MM's tree and list */
@@ -2085,14 +2085,14 @@ int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
down_write(&nommu_region_sem);
- mutex_lock(&inode->i_mapping->i_mmap_mutex);
+ i_mmap_lock_write(inode->i_mapping);
/* search for VMAs that fall within the dead zone */
vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) {
/* found one - only interested if it's shared out of the page
* cache */
if (vma->vm_flags & VM_SHARED) {
- mutex_unlock(&inode->i_mapping->i_mmap_mutex);
+ i_mmap_unlock_write(inode->i_mapping);
up_write(&nommu_region_sem);
return -ETXTBSY; /* not quite true, but near enough */
}
@@ -2120,7 +2120,7 @@ int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
}
}
- mutex_unlock(&inode->i_mapping->i_mmap_mutex);
+ i_mmap_unlock_write(inode->i_mapping);
up_write(&nommu_region_sem);
return 0;
}
diff --git a/mm/rmap.c b/mm/rmap.c
index fd3ee7a..29548e5 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -808,7 +808,7 @@ static int page_referenced_file(struct page *page,
*/
BUG_ON(!PageLocked(page));
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
/*
* i_mmap_mutex does not stabilize mapcount at all, but mapcount
@@ -831,7 +831,7 @@ static int page_referenced_file(struct page *page,
break;
}
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
return referenced;
}
@@ -917,14 +917,14 @@ static int page_mkclean_file(struct address_space *mapping, struct page *page)
BUG_ON(PageAnon(page));
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
if (vma->vm_flags & VM_SHARED) {
unsigned long address = vma_address(page, vma);
ret += page_mkclean_one(page, vma, address);
}
}
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
return ret;
}
@@ -1522,7 +1522,7 @@ static int try_to_unmap_file(struct page *page, enum ttu_flags flags)
if (PageHuge(page))
pgoff = page->index << compound_order(page);
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
unsigned long address = vma_address(page, vma);
ret = try_to_unmap_one(page, vma, address, flags);
@@ -1600,7 +1600,7 @@ static int try_to_unmap_file(struct page *page, enum ttu_flags flags)
list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.nonlinear)
vma->vm_private_data = NULL;
out:
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
return ret;
}
@@ -1717,7 +1717,7 @@ static int rmap_walk_file(struct page *page, int (*rmap_one)(struct page *,
if (!mapping)
return ret;
- mutex_lock(&mapping->i_mmap_mutex);
+ i_mmap_lock_write(mapping);
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
unsigned long address = vma_address(page, vma);
ret = rmap_one(page, vma, address, arg);
@@ -1729,7 +1729,7 @@ static int rmap_walk_file(struct page *page, int (*rmap_one)(struct page *,
* never contain migration ptes. Decide what to do about this
* limitation to linear when we need rmap_walk() on nonlinear.
*/
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_write(mapping);
return ret;
}
--
1.8.1.4
On Wed, 2 Oct 2013 13:17:45 -0700 Davidlohr Bueso <[email protected]> wrote:
> Various parts of the kernel acquire and release this mutex,
> so add i_mmap_lock_write() and immap_unlock_write() helper
> functions that will encapsulate this logic. The next patch
> will make use of these.
>
> ...
>
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -478,6 +478,16 @@ struct block_device {
>
> int mapping_tagged(struct address_space *mapping, int tag);
>
> +static inline void i_mmap_lock_write(struct address_space *mapping)
> +{
> + mutex_lock(&mapping->i_mmap_mutex);
> +}
I don't understand the thinking behind the "_write". There is no
"_read" and all callsites use "_write", so why not call it
i_mmap_lock()?
I *assume* the answer is "so we can later convert some sites to a new
i_mmap_lock_read()". If so, the changelog should have discussed this.
If not, still confused.
On Thu, 2013-10-03 at 13:58 -0700, Andrew Morton wrote:
> On Wed, 2 Oct 2013 13:17:45 -0700 Davidlohr Bueso <[email protected]> wrote:
>
> > Various parts of the kernel acquire and release this mutex,
> > so add i_mmap_lock_write() and immap_unlock_write() helper
> > functions that will encapsulate this logic. The next patch
> > will make use of these.
> >
> > ...
> >
> > --- a/include/linux/fs.h
> > +++ b/include/linux/fs.h
> > @@ -478,6 +478,16 @@ struct block_device {
> >
> > int mapping_tagged(struct address_space *mapping, int tag);
> >
> > +static inline void i_mmap_lock_write(struct address_space *mapping)
> > +{
> > + mutex_lock(&mapping->i_mmap_mutex);
> > +}
>
> I don't understand the thinking behind the "_write". There is no
> "_read" and all callsites use "_write", so why not call it
> i_mmap_lock()?
>
> I *assume* the answer is "so we can later convert some sites to a new
> i_mmap_lock_read()". If so, the changelog should have discussed this.
> If not, still confused.
>
Yes, that's exactly right. I'll resend with an updated changelog.
Thanks,
Davidlohr
On Thu, 2013-10-03 at 14:00 -0700, Davidlohr Bueso wrote:
> On Thu, 2013-10-03 at 13:58 -0700, Andrew Morton wrote:
> > On Wed, 2 Oct 2013 13:17:45 -0700 Davidlohr Bueso <[email protected]> wrote:
> >
> > > Various parts of the kernel acquire and release this mutex,
> > > so add i_mmap_lock_write() and immap_unlock_write() helper
> > > functions that will encapsulate this logic. The next patch
> > > will make use of these.
> > >
> > > ...
> > >
> > > --- a/include/linux/fs.h
> > > +++ b/include/linux/fs.h
> > > @@ -478,6 +478,16 @@ struct block_device {
> > >
> > > int mapping_tagged(struct address_space *mapping, int tag);
> > >
> > > +static inline void i_mmap_lock_write(struct address_space *mapping)
> > > +{
> > > + mutex_lock(&mapping->i_mmap_mutex);
> > > +}
> >
> > I don't understand the thinking behind the "_write". There is no
> > "_read" and all callsites use "_write", so why not call it
> > i_mmap_lock()?
> >
> > I *assume* the answer is "so we can later convert some sites to a new
> > i_mmap_lock_read()". If so, the changelog should have discussed this.
> > If not, still confused.
> >
>
> Yes, that's exactly right. I'll resend with an updated changelog.
So here's an updated changelog, I left it generic enough for us not to
rely on the lock type characteristics, since if/when changed, it can
remain a sleeping lock (rwsem) or not, for rwlock_t.
8<-----------------------------------------
From: Davidlohr Bueso <[email protected]>
Subject: [PATCH 1/2] mm,fs: introduce helpers around i_mmap_mutex
Various parts of the kernel acquire and release this mutex,
so add i_mmap_lock_write() and immap_unlock_write() helper
functions that will encapsulate this logic. The next patch
will make use of these.
Note that since this lock is currently a mutex, only introduce
write related functions. In the future, the lock type can be
changed and reading semantics can be added such that the lock
can be shared when allowed.
Signed-off-by: Davidlohr Bueso <[email protected]>
---
include/linux/fs.h | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3f40547..b32e64f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -478,6 +478,16 @@ struct block_device {
int mapping_tagged(struct address_space *mapping, int tag);
+static inline void i_mmap_lock_write(struct address_space *mapping)
+{
+ mutex_lock(&mapping->i_mmap_mutex);
+}
+
+static inline void i_mmap_unlock_write(struct address_space *mapping)
+{
+ mutex_unlock(&mapping->i_mmap_mutex);
+}
+
/*
* Might pages of this file be mapped into userspace?
*/
--
1.8.1.4