Re: [f2fs-dev] [PATCH] f2fs: cleanup the f2fs_bio_alloc routine

[Jaegeuk Kim <jaegeuk.kim@samsung.com>]

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2012-12-10 (월), 09:01 -0300, Ezequiel Garcia:
> On Mon, Dec 10, 2012 at 4:04 AM, Jaegeuk Kim <jaegeuk.kim@samsung.com> wrote:
> > Do cleanup more for better code readability.
> >
> > - Change the parameter set of f2fs_bio_alloc()
> >   This function should allocate a bio only since it is not something like
> >   f2fs_bio_init(). Instead, the caller should initialize the allocated bio.
> >
> > - Introduce SECTOR_FROM_BLOCK
> >   This macro translates a block address to its sector address.
> >
> > Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
> > ---
> >  fs/f2fs/data.c    |  5 +++--
> >  fs/f2fs/f2fs.h    |  2 +-
> >  fs/f2fs/segment.c | 33 ++++++++++++++++++---------------
> >  fs/f2fs/segment.h |  3 +++
> >  4 files changed, 25 insertions(+), 18 deletions(-)
> >
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index 444c2a6..655aeab 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -343,11 +343,12 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
> >         down_read(&sbi->bio_sem);
> >
> >         /* Allocate a new bio */
> > -       bio = f2fs_bio_alloc(bdev, blk_addr << (sbi->log_blocksize - 9),
> > -                               1, GFP_NOFS | __GFP_HIGH);
> > +       bio = f2fs_bio_alloc(bdev, 1);
> >
> >         /* Initialize the bio */
> > +       bio->bi_sector = SECTOR_FROM_BLOCK(sbi, blk_addr);
> >         bio->bi_end_io = read_end_io;
> > +
> >         if (bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < PAGE_CACHE_SIZE) {
> >                 kfree(bio->bi_private);
> >                 bio_put(bio);
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index 8c3f1ef..2bce3a6 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -924,7 +924,7 @@ void clear_prefree_segments(struct f2fs_sb_info *);
> >  int npages_for_summary_flush(struct f2fs_sb_info *);
> >  void allocate_new_segments(struct f2fs_sb_info *);
> >  struct page *get_sum_page(struct f2fs_sb_info *, unsigned int);
> > -struct bio *f2fs_bio_alloc(struct block_device *, sector_t, int, gfp_t);
> > +struct bio *f2fs_bio_alloc(struct block_device *, int);
> >  void f2fs_submit_bio(struct f2fs_sb_info *, enum page_type, bool sync);
> >  int write_meta_page(struct f2fs_sb_info *, struct page *,
> >                                         struct writeback_control *);
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index 8894b39..1b26e4e 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -643,23 +643,21 @@ static void f2fs_end_io_write(struct bio *bio, int err)
> >         bio_put(bio);
> >  }
> >
> > -struct bio *f2fs_bio_alloc(struct block_device *bdev, sector_t first_sector,
> > -                                       int nr_vecs, gfp_t gfp_flags)
> > +struct bio *f2fs_bio_alloc(struct block_device *bdev, int npages)
> >  {
> >         struct bio *bio;
> > -
> > -       /* allocate new bio */
> > -       bio = bio_alloc(gfp_flags, nr_vecs);
> > -
> > -       bio->bi_bdev = bdev;
> > -       bio->bi_sector = first_sector;
> > +       struct bio_private *priv;
> >  retry:
> > -       bio->bi_private = kmalloc(sizeof(struct bio_private),
> > -                                       GFP_NOFS | __GFP_HIGH);
> > -       if (!bio->bi_private) {
> > +       priv = kmalloc(sizeof(struct bio_private), GFP_NOFS);
> 
> Suggestion:
> 
> Given you're writing a f2fs specific allocator wrapper for kmalloc,
> you might want to use kmalloc_track_caller and friends.
> 
> This way, if you use ftrace kmem events you'll be able to track
> the real caller, instead of f2fs_bio_alloc.

Ok, I'll keep in mind.
But, well, currently it seems there is no need to use that.
Thanks,

> 
> Thanks,
> 
>     Ezequiel
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-- 
Jaegeuk Kim
Samsung

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