Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 82591e6e authored Oct 19, 2006 by Nick Piggin Committed by Linus Torvalds Oct 20, 2006

[PATCH] mm: more commenting on lock ordering



Clarify lockorder comments now that sys_msync dropps mmap_sem before
calling do_fsync.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent b95936cb

mm/filemap.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -75,8 +75,8 @@ generic_file_direct_IO(int rw, struct kiocb iocb, const struct iovec iov,
		* ->mmap_sem
		* ->lock_page (access_process_vm)
		*
		* ->mmap_sem
		* ->i_mutex (msync)
		* ->i_mutex (generic_file_buffered_write)
		* ->mmap_sem (fault_in_pages_readable->do_page_fault)
		*
		* ->i_mutex
		* ->i_alloc_sem (various)

mm/rmap.c

+15 −21

Original line number	Diff line number	Diff line
		@@ -21,13 +21,7 @@
		* Lock ordering in mm:
		*
		* inode->i_mutex (while writing or truncating, not reading or faulting)
		* inode->i_alloc_sem
		*
		* When a page fault occurs in writing from user to file, down_read
		* of mmap_sem nests within i_mutex; in sys_msync, i_mutex nests within
		* down_read of mmap_sem; i_mutex and down_write of mmap_sem are never
		* taken together; in truncation, i_mutex is taken outermost.
		*
		* inode->i_alloc_sem (vmtruncate_range)
		* mm->mmap_sem
		* page->flags PG_locked (lock_page)
		* mapping->i_mmap_lock