Messages in this thread Patch in this message | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH -mm] swsusp: Freeze filesystems during suspend (rev. 2) | Date | Wed, 1 Nov 2006 21:22:41 +0100 |
| |
On Wednesday, 1 November 2006 20:54, Andrew Morton wrote: > On Wed, 1 Nov 2006 18:53:07 +0100 > "Rafael J. Wysocki" <rjw@sisk.pl> wrote: > > > +void freeze_filesystems(void) > > +{ > > + struct super_block *sb; > > + > > + lockdep_off(); > > + /* > > + * Freeze in reverse order so filesystems dependant upon others are > > + * frozen in the right order (eg. loopback on ext3). > > + */ > > + list_for_each_entry_reverse(sb, &super_blocks, s_list) { > > + if (!sb->s_root || !sb->s_bdev || > > + (sb->s_frozen == SB_FREEZE_TRANS) || > > + (sb->s_flags & MS_RDONLY) || > > + (sb->s_flags & MS_FROZEN)) > > + continue; > > + > > + freeze_bdev(sb->s_bdev); > > + sb->s_flags |= MS_FROZEN; > > + } > > + lockdep_on(); > > +} > > + > > +/** > > + * thaw_filesystems - unlock all filesystems > > + */ > > +void thaw_filesystems(void) > > +{ > > + struct super_block *sb; > > + > > + lockdep_off(); > > + > > + list_for_each_entry(sb, &super_blocks, s_list) > > + if (sb->s_flags & MS_FROZEN) { > > + sb->s_flags &= ~MS_FROZEN; > > + thaw_bdev(sb->s_bdev, sb); > > + } > > + > > + lockdep_on(); > > +} > > argh. > > The uncommented, unchangelogged lockdep_off() calls are completely > mysterious right now, even before the patch is merged. They will not > become less mysterious over time.
Of course. Sorry.
> Please, take pity upon the readers of your code. Add a comment.
OK (on top of the previous patch)
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> --- fs/buffer.c | 9 +++++++++ 1 file changed, 9 insertions(+)
Index: linux-2.6.19-rc4-mm1/fs/buffer.c =================================================================== --- linux-2.6.19-rc4-mm1.orig/fs/buffer.c +++ linux-2.6.19-rc4-mm1/fs/buffer.c @@ -252,6 +252,11 @@ void freeze_filesystems(void) { struct super_block *sb; + /* + * We are going to take several locks of the same class in a row + * without releasing them until thaw_filesystems() is called and + * lockdep won't know this is all OK. + */ lockdep_off(); /* * Freeze in reverse order so filesystems dependant upon others are @@ -277,6 +282,10 @@ void thaw_filesystems(void) { struct super_block *sb; + /* + * We are going to release several locks of the same class in a row + * and lockdep would complain about it, unnecessarily. + */ lockdep_off(); list_for_each_entry(sb, &super_blocks, s_list) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |