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Commit 3dec0ba0 authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Linus Torvalds
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mm/rmap: share the i_mmap_rwsem 



Similarly to the anon memory counterpart, we can share the mapping's lock
ownership as the interval tree is not modified when doing doing the walk,
only the file page.

Signed-off-by: default avatarDavidlohr Bueso <dbueso@suse.de>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Acked-by: default avatar"Kirill A. Shutemov" <kirill@shutemov.name>
Acked-by: default avatarHugh Dickins <hughd@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: default avatarMel Gorman <mgorman@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c8c06efa

include/linux/fs.h

+10 −0
Original line number Diff line number Diff line
@@ -478,6 +478,16 @@ static inline void i_mmap_unlock_write(struct address_space *mapping) 
	up_write(&mapping->i_mmap_rwsem);

}



static inline void i_mmap_lock_read(struct address_space *mapping)

{

	down_read(&mapping->i_mmap_rwsem);

}



static inline void i_mmap_unlock_read(struct address_space *mapping)

{

	up_read(&mapping->i_mmap_rwsem);

}



/*

 * Might pages of this file be mapped into userspace?

 */

mm/rmap.c

+3 −3
Original line number Diff line number Diff line
@@ -1690,7 +1690,8 @@ static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc) 


	if (!mapping)

		return ret;

	i_mmap_lock_write(mapping);



	i_mmap_lock_read(mapping);

	vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {

		unsigned long address = vma_address(page, vma);
@@ -1711,9 +1712,8 @@ static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc) 
		goto done;



	ret = rwc->file_nonlinear(page, mapping, rwc->arg);



done:

	i_mmap_unlock_write(mapping);

	i_mmap_unlock_read(mapping);

	return ret;

}