On Mon, 25 Jun 2012 15:24:54 +0800 Shaohua Li <shli@xxxxxxxxxx> wrote:
> Allow personality providing unplug private data. Next patch will use it.
Thanks. I've applied this with a couple of minor changes.
In particular I change the 'size' arg to be size total size of the
plug structure, not the amount to add to the end. I also change it
to use kzalloc rather then an extra memset.
Thanks,
NeilBrown
>
> Signed-off-by: Shaohua Li <shli@xxxxxxxxxxxx>
> ---
> drivers/md/md.c | 31 +++++++++++++------------------
> drivers/md/md.h | 20 +++++++++++++++++++-
> drivers/md/raid1.c | 2 +-
> drivers/md/raid10.c | 2 +-
> drivers/md/raid5.c | 2 +-
> 5 files changed, 35 insertions(+), 22 deletions(-)
>
> Index: linux/drivers/md/md.c
> ===================================================================
> --- linux.orig/drivers/md/md.c 2012-06-25 14:36:13.668642048 +0800
> +++ linux/drivers/md/md.c 2012-06-25 14:38:33.106889041 +0800
> @@ -498,22 +498,13 @@ void md_flush_request(struct mddev *mdde
> }
> EXPORT_SYMBOL(md_flush_request);
>
> -/* Support for plugging.
> - * This mirrors the plugging support in request_queue, but does not
> - * require having a whole queue or request structures.
> - * We allocate an md_plug_cb for each md device and each thread it gets
> - * plugged on. This links tot the private plug_handle structure in the
> - * personality data where we keep a count of the number of outstanding
> - * plugs so other code can see if a plug is active.
> - */
> -struct md_plug_cb {
> - struct blk_plug_cb cb;
> - struct mddev *mddev;
> -};
>
> static void plugger_unplug(struct blk_plug_cb *cb)
> {
> struct md_plug_cb *mdcb = container_of(cb, struct md_plug_cb, cb);
> +
> + if (mdcb->unplug)
> + mdcb->unplug(mdcb);
> if (atomic_dec_and_test(&mdcb->mddev->plug_cnt))
> md_wakeup_thread(mdcb->mddev->thread);
> kfree(mdcb);
> @@ -522,13 +513,14 @@ static void plugger_unplug(struct blk_pl
> /* Check that an unplug wakeup will come shortly.
> * If not, wakeup the md thread immediately
> */
> -int mddev_check_plugged(struct mddev *mddev)
> +struct md_plug_cb *mddev_check_plugged(struct mddev *mddev,
> + md_unplug_func_t unplug, size_t size)
> {
> struct blk_plug *plug = current->plug;
> struct md_plug_cb *mdcb;
>
> if (!plug)
> - return 0;
> + return NULL;
>
> list_for_each_entry(mdcb, &plug->cb_list, cb.list) {
> if (mdcb->cb.callback == plugger_unplug &&
> @@ -538,19 +530,22 @@ int mddev_check_plugged(struct mddev *md
> struct md_plug_cb,
> cb.list))
> list_move(&mdcb->cb.list, &plug->cb_list);
> - return 1;
> + return mdcb;
> }
> }
> /* Not currently on the callback list */
> - mdcb = kmalloc(sizeof(*mdcb), GFP_ATOMIC);
> + mdcb = kmalloc(sizeof(*mdcb) + size, GFP_ATOMIC);
> if (!mdcb)
> - return 0;
> + return NULL;
>
> mdcb->mddev = mddev;
> mdcb->cb.callback = plugger_unplug;
> atomic_inc(&mddev->plug_cnt);
> list_add(&mdcb->cb.list, &plug->cb_list);
> - return 1;
> + mdcb->unplug = unplug;
> + if (size)
> + memset((void *)(mdcb + 1), 0, size);
> + return mdcb;
> }
> EXPORT_SYMBOL_GPL(mddev_check_plugged);
>
> Index: linux/drivers/md/md.h
> ===================================================================
> --- linux.orig/drivers/md/md.h 2012-06-25 14:36:13.676641948 +0800
> +++ linux/drivers/md/md.h 2012-06-25 14:38:33.106889041 +0800
> @@ -630,6 +630,24 @@ extern struct bio *bio_clone_mddev(struc
> struct mddev *mddev);
> extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
> struct mddev *mddev);
> -extern int mddev_check_plugged(struct mddev *mddev);
> +
> +/* Support for plugging.
> + * This mirrors the plugging support in request_queue, but does not
> + * require having a whole queue or request structures.
> + * We allocate an md_plug_cb for each md device and each thread it gets
> + * plugged on. This links tot the private plug_handle structure in the
> + * personality data where we keep a count of the number of outstanding
> + * plugs so other code can see if a plug is active.
> + */
> +struct md_plug_cb;
> +typedef void (*md_unplug_func_t)(struct md_plug_cb *mdcb);
> +struct md_plug_cb {
> + struct blk_plug_cb cb;
> + struct mddev *mddev;
> + md_unplug_func_t unplug;
> +};
> +
> +extern struct md_plug_cb *mddev_check_plugged(struct mddev *mddev,
> + md_unplug_func_t unplug, size_t size);
> extern void md_trim_bio(struct bio *bio, int offset, int size);
> #endif /* _MD_MD_H */
> Index: linux/drivers/md/raid1.c
> ===================================================================
> --- linux.orig/drivers/md/raid1.c 2012-06-25 14:36:13.696641695 +0800
> +++ linux/drivers/md/raid1.c 2012-06-25 14:38:33.110889008 +0800
> @@ -1034,7 +1034,7 @@ read_again:
> * the bad blocks. Each set of writes gets it's own r1bio
> * with a set of bios attached.
> */
> - plugged = mddev_check_plugged(mddev);
> + plugged = !!mddev_check_plugged(mddev, NULL, 0);
>
> disks = conf->raid_disks * 2;
> retry_write:
> Index: linux/drivers/md/raid10.c
> ===================================================================
> --- linux.orig/drivers/md/raid10.c 2012-06-25 14:36:13.684641847 +0800
> +++ linux/drivers/md/raid10.c 2012-06-25 14:38:33.110889008 +0800
> @@ -1239,7 +1239,7 @@ read_again:
> * of r10_bios is recored in bio->bi_phys_segments just as with
> * the read case.
> */
> - plugged = mddev_check_plugged(mddev);
> + plugged = !!mddev_check_plugged(mddev, NULL, 0);
>
> r10_bio->read_slot = -1; /* make sure repl_bio gets freed */
> raid10_find_phys(conf, r10_bio);
> Index: linux/drivers/md/raid5.c
> ===================================================================
> --- linux.orig/drivers/md/raid5.c 2012-06-25 14:38:13.899130571 +0800
> +++ linux/drivers/md/raid5.c 2012-06-25 14:38:33.110889008 +0800
> @@ -4012,7 +4012,7 @@ static void make_request(struct mddev *m
> bi->bi_next = NULL;
> bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
>
> - plugged = mddev_check_plugged(mddev);
> + plugged = !!mddev_check_plugged(mddev, NULL, 0);
> for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
> DEFINE_WAIT(w);
> int previous;
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