It causes NULL pointer error without f2fs_bug_on(), so I don't think we need to add this. Thanks, 2013-12-02 (월), 16:59 +0800, Chao Yu: > Hi Kim, > > > -----Original Message----- > > From: Jaegeuk Kim [mailto:jaegeuk.kim@xxxxxxxxxxx] > > Sent: Monday, December 02, 2013 4:15 PM > > To: Chao Yu > > Cc: linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx; 谭姝 > > Subject: RE: [f2fs-dev] [PATCH] f2fs: remove the own bi_private allocation > > > > 2013-12-02 (월), 14:14 +0800, Chao Yu: > > > Hi Kim, > > > > > > > -----Original Message----- > > > > From: Jaegeuk Kim [mailto:jaegeuk.kim@xxxxxxxxxxx] > > > > Sent: Saturday, November 30, 2013 9:48 AM > > > > Cc: linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > > > > Subject: [f2fs-dev] [PATCH] f2fs: remove the own bi_private allocation > > > > > > > > Previously f2fs allocates its own bi_private data structure all the time even > > > > though we don't use it. But, can we remove this bi_private allocation? > > > > > > > > This patch removes such the additional bi_private allocation. > > > > > > > > 1. Retrieve f2fs_sb_info from its page->mapping->host->i_sb. > > > > - This removes the usecases of bi_private in end_io. > > > > > > > > 2. Use bi_private only when we really need it. > > > > - The bi_private is used only when the checkpoint procedure is conducted. > > > > - When conducting the checkpoint, f2fs submits a META_FLUSH bio to wait its bio > > > > completion. > > > > - Since we have no dependancies to remove bi_private now, let's just use > > > > bi_private pointer as the completion pointer. > > > > > > > > Signed-off-by: Jaegeuk Kim <jaegeuk.kim@xxxxxxxxxxx> > > > > --- > > > > fs/f2fs/segment.c | 43 ++++++++++++++++--------------------------- > > > > fs/f2fs/segment.h | 7 ------- > > > > 2 files changed, 16 insertions(+), 34 deletions(-) > > > > > > > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > > > > index 0387863..0db4027 100644 > > > > --- a/fs/f2fs/segment.c > > > > +++ b/fs/f2fs/segment.c > > > > @@ -791,7 +791,7 @@ static void f2fs_end_io_write(struct bio *bio, int err) > > > > { > > > > const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); > > > > struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; > > > > - struct bio_private *p = bio->bi_private; > > f2fs_bug_on(unlikely(!bvec->bv_page->mapping)); > > > > > + struct f2fs_sb_info *sbi = F2FS_SB(bvec->bv_page->mapping->host->i_sb); > > > > > > I'm not sure whether bvec->bv_page->mapping will be set to NULL in the flow > > > where may not check WRITEBACK flag of page. Is it possible? > > > > The mapping should be not NULL cause it is a writebacking page. > > Otherwise, it's a bug. > > If so, should we add additional code as above? > > Regards, > Yu > > > Thanks, > > > > -- > > Jaegeuk Kim > > Samsung > > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Jaegeuk Kim Samsung -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
