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authorDavidlohr Bueso <dave@stgolabs.net>2014-12-12 16:54:24 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-13 12:42:45 -0800
commitc8c06efa8b552608493b7066c234cfa82c47fcea (patch)
tree7e206c669149766fb5a77a3ef85cdd4fac63be78 /include
parent83cde9e8ba95d180eaefefe834958fbf7008cf39 (diff)
mm: convert i_mmap_mutex to rwsem
The i_mmap_mutex is a close cousin of the anon vma lock, both protecting similar data, one for file backed pages and the other for anon memory. To this end, this lock can also be a rwsem. In addition, there are some important opportunities to share the lock when there are no tree modifications. This conversion is straightforward. For now, all users take the write lock. [sfr@canb.auug.org.au: update fremap.c] Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name> Acked-by: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/fs.h7
-rw-r--r--include/linux/mmu_notifier.h2
2 files changed, 5 insertions, 4 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h
index bd0a1b2f3c02..6abcd0b72ae0 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -18,6 +18,7 @@
#include <linux/pid.h>
#include <linux/bug.h>
#include <linux/mutex.h>
+#include <linux/rwsem.h>
#include <linux/capability.h>
#include <linux/semaphore.h>
#include <linux/fiemap.h>
@@ -401,7 +402,7 @@ struct address_space {
atomic_t i_mmap_writable;/* count VM_SHARED mappings */
struct rb_root i_mmap; /* tree of private and shared mappings */
struct list_head i_mmap_nonlinear;/*list VM_NONLINEAR mappings */
- struct mutex i_mmap_mutex; /* protect tree, count, list */
+ struct rw_semaphore i_mmap_rwsem; /* protect tree, count, list */
/* Protected by tree_lock together with the radix tree */
unsigned long nrpages; /* number of total pages */
unsigned long nrshadows; /* number of shadow entries */
@@ -469,12 +470,12 @@ 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);
+ down_write(&mapping->i_mmap_rwsem);
}
static inline void i_mmap_unlock_write(struct address_space *mapping)
{
- mutex_unlock(&mapping->i_mmap_mutex);
+ up_write(&mapping->i_mmap_rwsem);
}
/*
diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
index 88787bb4b3b9..ab8564b03468 100644
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -154,7 +154,7 @@ 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 {