mm/memory.c: share the i_mmap_rwsem

The unmap_mapping_range family of functions do the unmapping of user pages
(ultimately via zap_page_range_single) without touching the actual
interval tree, thus share the lock.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memory.c b/mm/memory.c
index 039fab6..5afdb5b 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2377,12 +2377,12 @@ void unmap_mapping_range(struct address_space *mapping,
                details.last_index = ULONG_MAX;
 
 
-       i_mmap_lock_write(mapping);
+       i_mmap_lock_read(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);
-       i_mmap_unlock_write(mapping);
+       i_mmap_unlock_read(mapping);
 }
 EXPORT_SYMBOL(unmap_mapping_range);