[PATCH 1/1] UBUNTU: ubuntu: Add dm-raid4-5 driver -- port to 2.6.28

[Jim Lieb]

How does this fit in with the lockless changes in .27?  Are we re-introducing
some locking where it is not used elsewhere?

On Wednesday 24 December 2008 02:53:36 Andy Whitcroft wrote:
> Bug: #309378
>
> The dm-raid4-5 driver was disabled as it did not cleanly compile when
> rebased to 2.6.28.  This was due to two errors:
>
> 1) the removal of {set,clear}_page_locked() as the atomic versions were
>    no longer used elsewhere in the kernel, and
> 2) the array_too_big() function was renamed to dm_array_too_big() to
>    allow it to be exported.
>
> As raid is a highly critical subsystem I have taken the safest possible
> approach and assumed that RAID does require the atomic flag modifiers.
> This patch therefore reinstates {set,clear}_page_locked() and moves the
> code to using the new dm_array_too_big() interface.  Finally it reenabled
> the raid support.
>
> I have deliberatly re-introduced {set,clear}_page_locked() into the
> original headers next to their corresponding unlocked form such that
> should those change again we will conflict and detect the change.
>
> Signed-off-by: Andy Whitcroft <apw at canonical.com>
> ---
>  include/linux/pagemap.h        |    8 ++++++++
>  ubuntu/dm-raid4-5/Makefile     |    2 +-
>  ubuntu/dm-raid4-5/dm-raid4-5.c |    2 +-
>  3 files changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index 709742b..f09e3b2 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -303,11 +303,19 @@ static inline void __set_page_locked(struct page
> *page) {
>  	__set_bit(PG_locked, &page->flags);
>  }
> +static inline void set_page_locked(struct page *page)
> +{
> +	set_bit(PG_locked, &page->flags);
> +}
>
>  static inline void __clear_page_locked(struct page *page)
>  {
>  	__clear_bit(PG_locked, &page->flags);
>  }
> +static inline void clear_page_locked(struct page *page)
> +{
> +	clear_bit(PG_locked, &page->flags);
> +}
>
>  static inline int trylock_page(struct page *page)
>  {
> diff --git a/ubuntu/dm-raid4-5/Makefile b/ubuntu/dm-raid4-5/Makefile
> index b33ce8d..3a7e2fb 100644
> --- a/ubuntu/dm-raid4-5/Makefile
> +++ b/ubuntu/dm-raid4-5/Makefile
> @@ -1,3 +1,3 @@
>  EXTRA_CFLAGS += -I$(srctree)/drivers/md
>
> -#obj-$(CONFIG_DM_RAID45) += dm-raid4-5.o dm-mem-cache.o dm-region_hash.o
> dm-message.o +obj-$(CONFIG_DM_RAID45) += dm-raid4-5.o dm-mem-cache.o
> dm-region_hash.o dm-message.o diff --git a/ubuntu/dm-raid4-5/dm-raid4-5.c
> b/ubuntu/dm-raid4-5/dm-raid4-5.c index 156a219..73dc5e2 100644
> --- a/ubuntu/dm-raid4-5/dm-raid4-5.c
> +++ b/ubuntu/dm-raid4-5/dm-raid4-5.c
> @@ -3296,7 +3296,7 @@ context_alloc(struct raid_set **raid_set, struct
> raid_type *raid_type,
>
>  	/* Size and allocate the RAID set structure. */
>  	len = sizeof(*rs->data) + sizeof(*rs->dev);
> -	if (array_too_big(sizeof(*rs), len, raid_devs))
> +	if (dm_array_too_big(sizeof(*rs), len, raid_devs))
>  		goto bad_array;
>
>  	len = sizeof(*rs) + raid_devs * len;
> --
> 1.6.0.4.911.gc990

-- 
Jim Lieb
Ubuntu Kernel Team
Canonical Ltd.