Re: [f2fs-dev] [PATCH] f2fs: add a way to turn off ipu bio cache

[Jaegeuk Kim]

On 01/08, Chao Yu wrote:
> On 2020/1/8 20:04, Jaegeuk Kim wrote:
> > On 01/08, Chao Yu wrote:
> >> On 2020/1/7 10:07, Jaegeuk Kim wrote:
> >>> Setting 0x40 in /sys/fs/f2fs/dev/ipu_policy gives a way to turn off
> >>> bio cache, which is useufl to check whether block layer using hardware
> >>> encryption engine merges IOs correctly.
> >>>
> >>> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> >>> ---
> >>>  Documentation/filesystems/f2fs.txt | 1 +
> >>>  fs/f2fs/segment.c                  | 2 +-
> >>>  fs/f2fs/segment.h                  | 1 +
> >>>  3 files changed, 3 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
> >>> index 41b5aa94b30f..cd93bcc34726 100644
> >>> --- a/Documentation/filesystems/f2fs.txt
> >>> +++ b/Documentation/filesystems/f2fs.txt
> >>> @@ -335,6 +335,7 @@ Files in /sys/fs/f2fs/<devname>
> >>>                                 0x01: F2FS_IPU_FORCE, 0x02: F2FS_IPU_SSR,
> >>>                                 0x04: F2FS_IPU_UTIL,  0x08: F2FS_IPU_SSR_UTIL,
> >>>                                 0x10: F2FS_IPU_FSYNC.
> >>
> >> . -> ,
> > 
> > Actually, we can't do it. I revised it a bit instead.
> 
> One more question, why skipping 0x20 bit position?

It seems original patch missed to add comment.