On 07/24/2012 11:11 PM, Kent Overstreet wrote:

> This is prep work for killing bi_destructor - previously, pktcdvd had
> its own pkt_bio_alloc which was basically duplication bio_kmalloc(),
> necessitating its own bi_destructor implementation.
> 
> Signed-off-by: Kent Overstreet <koverstr...@google.com>
> ---
>  drivers/block/pktcdvd.c |  115 
> ++++++++++++++++-------------------------------
>  1 files changed, 39 insertions(+), 76 deletions(-)
> 
> diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
> index ba66e44..6fe693a 100644
> --- a/drivers/block/pktcdvd.c
> +++ b/drivers/block/pktcdvd.c
> @@ -522,36 +522,38 @@ static void pkt_bio_finished(struct pktcdvd_device *pd)
>       }
>  }
>  
> -static void pkt_bio_destructor(struct bio *bio)
> +static void pkt_end_io_read(struct bio *bio, int err)
>  {
> -     kfree(bio->bi_io_vec);
> -     kfree(bio);
> -}


Again here, you decided to move the pkt_end_io_read && pkt_end_io_packet_write
functions from below, to above here. Which makes it impossible to find
any bugs by just reviewing the patch.

So I have not reviewed it. 

I know that you wanted so you can reference them at pkt_alloc_packet_data.
I'd use a forward reference, in this case. And a move in a next patch. But
this is just me. Perhaps the owner of this code can review it?

Cheers
Boaz

> +     struct packet_data *pkt = bio->bi_private;
> +     struct pktcdvd_device *pd = pkt->pd;
> +     BUG_ON(!pd);
>  
> -static struct bio *pkt_bio_alloc(int nr_iovecs)
> -{
> -     struct bio_vec *bvl = NULL;
> -     struct bio *bio;
> +     VPRINTK("pkt_end_io_read: bio=%p sec0=%llx sec=%llx err=%d\n", bio,
> +             (unsigned long long)pkt->sector, (unsigned long 
> long)bio->bi_sector, err);
>  
> -     bio = kmalloc(sizeof(struct bio), GFP_KERNEL);
> -     if (!bio)
> -             goto no_bio;
> -     bio_init(bio);
> +     if (err)
> +             atomic_inc(&pkt->io_errors);
> +     if (atomic_dec_and_test(&pkt->io_wait)) {
> +             atomic_inc(&pkt->run_sm);
> +             wake_up(&pd->wqueue);
> +     }
> +     pkt_bio_finished(pd);
> +}
>  
> -     bvl = kcalloc(nr_iovecs, sizeof(struct bio_vec), GFP_KERNEL);
> -     if (!bvl)
> -             goto no_bvl;
> +static void pkt_end_io_packet_write(struct bio *bio, int err)
> +{
> +     struct packet_data *pkt = bio->bi_private;
> +     struct pktcdvd_device *pd = pkt->pd;
> +     BUG_ON(!pd);
>  
> -     bio->bi_max_vecs = nr_iovecs;
> -     bio->bi_io_vec = bvl;
> -     bio->bi_destructor = pkt_bio_destructor;
> +     VPRINTK("pkt_end_io_packet_write: id=%d, err=%d\n", pkt->id, err);
>  
> -     return bio;
> +     pd->stats.pkt_ended++;
>  
> - no_bvl:
> -     kfree(bio);
> - no_bio:
> -     return NULL;
> +     pkt_bio_finished(pd);
> +     atomic_dec(&pkt->io_wait);
> +     atomic_inc(&pkt->run_sm);
> +     wake_up(&pd->wqueue);
>  }
>  
>  /*
> @@ -567,10 +569,13 @@ static struct packet_data *pkt_alloc_packet_data(int 
> frames)
>               goto no_pkt;
>  
>       pkt->frames = frames;
> -     pkt->w_bio = pkt_bio_alloc(frames);
> +     pkt->w_bio = bio_kmalloc(GFP_KERNEL, frames);
>       if (!pkt->w_bio)
>               goto no_bio;
>  
> +     pkt->w_bio->bi_end_io = pkt_end_io_packet_write;
> +     pkt->w_bio->bi_private = pkt;
> +
>       for (i = 0; i < frames / FRAMES_PER_PAGE; i++) {
>               pkt->pages[i] = alloc_page(GFP_KERNEL|__GFP_ZERO);
>               if (!pkt->pages[i])
> @@ -581,9 +586,12 @@ static struct packet_data *pkt_alloc_packet_data(int 
> frames)
>       bio_list_init(&pkt->orig_bios);
>  
>       for (i = 0; i < frames; i++) {
> -             struct bio *bio = pkt_bio_alloc(1);
> +             struct bio *bio = bio_kmalloc(GFP_KERNEL, 1);
>               if (!bio)
>                       goto no_rd_bio;
> +
> +             bio->bi_end_io = pkt_end_io_read;
> +             bio->bi_private = pkt;
>               pkt->r_bios[i] = bio;
>       }
>  
> @@ -1036,40 +1044,6 @@ static void pkt_make_local_copy(struct packet_data 
> *pkt, struct bio_vec *bvec)
>       }
>  }
>  
> -static void pkt_end_io_read(struct bio *bio, int err)
> -{
> -     struct packet_data *pkt = bio->bi_private;
> -     struct pktcdvd_device *pd = pkt->pd;
> -     BUG_ON(!pd);
> -
> -     VPRINTK("pkt_end_io_read: bio=%p sec0=%llx sec=%llx err=%d\n", bio,
> -             (unsigned long long)pkt->sector, (unsigned long 
> long)bio->bi_sector, err);
> -
> -     if (err)
> -             atomic_inc(&pkt->io_errors);
> -     if (atomic_dec_and_test(&pkt->io_wait)) {
> -             atomic_inc(&pkt->run_sm);
> -             wake_up(&pd->wqueue);
> -     }
> -     pkt_bio_finished(pd);
> -}
> -
> -static void pkt_end_io_packet_write(struct bio *bio, int err)
> -{
> -     struct packet_data *pkt = bio->bi_private;
> -     struct pktcdvd_device *pd = pkt->pd;
> -     BUG_ON(!pd);
> -
> -     VPRINTK("pkt_end_io_packet_write: id=%d, err=%d\n", pkt->id, err);
> -
> -     pd->stats.pkt_ended++;
> -
> -     pkt_bio_finished(pd);
> -     atomic_dec(&pkt->io_wait);
> -     atomic_inc(&pkt->run_sm);
> -     wake_up(&pd->wqueue);
> -}
> -
>  /*
>   * Schedule reads for the holes in a packet
>   */
> @@ -1111,21 +1085,15 @@ static void pkt_gather_data(struct pktcdvd_device 
> *pd, struct packet_data *pkt)
>        * Schedule reads for missing parts of the packet.
>        */
>       for (f = 0; f < pkt->frames; f++) {
> -             struct bio_vec *vec;
> -
>               int p, offset;
> +
>               if (written[f])
>                       continue;
> +
>               bio = pkt->r_bios[f];
> -             vec = bio->bi_io_vec;
> -             bio_init(bio);
> -             bio->bi_max_vecs = 1;
> -             bio->bi_sector = pkt->sector + f * (CD_FRAMESIZE >> 9);
> -             bio->bi_bdev = pd->bdev;
> -             bio->bi_end_io = pkt_end_io_read;
> -             bio->bi_private = pkt;
> -             bio->bi_io_vec = vec;
> -             bio->bi_destructor = pkt_bio_destructor;
> +             bio_reset(bio);
> +             bio->bi_sector  = pkt->sector + f * (CD_FRAMESIZE >> 9);
> +             bio->bi_bdev    = pd->bdev;
>  
>               p = (f * CD_FRAMESIZE) / PAGE_SIZE;
>               offset = (f * CD_FRAMESIZE) % PAGE_SIZE;
> @@ -1418,14 +1386,9 @@ static void pkt_start_write(struct pktcdvd_device *pd, 
> struct packet_data *pkt)
>       }
>  
>       /* Start the write request */
> -     bio_init(pkt->w_bio);
> -     pkt->w_bio->bi_max_vecs = PACKET_MAX_SIZE;
> +     bio_reset(pkt->w_bio);
>       pkt->w_bio->bi_sector = pkt->sector;
>       pkt->w_bio->bi_bdev = pd->bdev;
> -     pkt->w_bio->bi_end_io = pkt_end_io_packet_write;
> -     pkt->w_bio->bi_private = pkt;
> -     pkt->w_bio->bi_io_vec = bvec;
> -     pkt->w_bio->bi_destructor = pkt_bio_destructor;
>       for (f = 0; f < pkt->frames; f++)
>               if (!bio_add_page(pkt->w_bio, bvec[f].bv_page, CD_FRAMESIZE, 
> bvec[f].bv_offset))
>                       BUG();


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