[openib-general] [PATCH v3 3/3] ofed_1_2 Provide generic allocator backport to 2.6.20.

[Michael S. Tsirkin]

> Quoting Steve Wise <swise at opengridcomputing.com>:
> Subject: [PATCH  v3 3/3] ofed_1_2 Provide generic allocator backport to 2.6.20.
> 
> 
> This is needed even on kernels that might have genalloc because it
> may not be configured into the running kernel.  Right now the only
> subsystem that turns on the generic allocator config option is IA64.
> So chances are good that 2.6.20 kernels will _not_ have this compiled in.
> So we just backport it to all supported kernels.
> 
> To avoid collisions with kernels that _do_ have this compiled in, 
> change the names of the exported symbols in the backport.
> 
> Changes to genalloc.c:
> 
> - Change exported symbol names by prepending ib_
>   EG: gen_pool_alloc() becomes ib_gen_pool_alloc()
> 
> Changes to genalloc.h:
> 
> - Change exported symbol names by prepending ib_
> - added #defines for original exported symbol names to new names. Thus
>   code calling the allocator doesn't need to change.
> 
>   EG: #define gen_pool_alloc ib_gen_pool alloc
> 
> Signed-off-by: Steve Wise <swise at opengridcomputing.com>
> ---
> 
>  .../backport/2.6.20/include/linux/genalloc.h       |   42 +++++
>  .../backport/2.6.20/include/src/genalloc.c         |  198 +++++++++++++++++++++++
>  .../backport/2.6.20/linux_genalloc_to_2.6.20.patch |   18 ++
>  3 files changed, 258 insertions(+), 0 deletions(-)
> 
> diff --git a/kernel_addons/backport/2.6.20/include/linux/genalloc.h b/kernel_addons/backport/2.6.20/include/linux/genalloc.h
> new file mode 100644
> index 0000000..3c23c68
> --- /dev/null
> +++ b/kernel_addons/backport/2.6.20/include/linux/genalloc.h
> @@ -0,0 +1,42 @@
> +/*
> + * Basic general purpose allocator for managing special purpose memory
> + * not managed by the regular kmalloc/kfree interface.
> + * Uses for this includes on-device special memory, uncached memory
> + * etc.
> + *
> + * This source code is licensed under the GNU General Public License,
> + * Version 2.  See the file COPYING for more details.
> + */
> +
> +
> +/*
> + *  General purpose special memory pool descriptor.
> + */
> +struct gen_pool {
> +	rwlock_t lock;
> +	struct list_head chunks;	/* list of chunks in this pool */
> +	int min_alloc_order;		/* minimum allocation order */
> +};
> +
> +/*
> + *  General purpose special memory pool chunk descriptor.
> + */
> +struct gen_pool_chunk {
> +	spinlock_t lock;
> +	struct list_head next_chunk;	/* next chunk in pool */
> +	unsigned long start_addr;	/* starting address of memory chunk */
> +	unsigned long end_addr;		/* ending address of memory chunk */
> +	unsigned long bits[0];		/* bitmap for allocating memory chunk */
> +};
> +
> +extern struct gen_pool *ib_gen_pool_create(int, int);

If you think about it, by virtue of the defines above, genalloc.c
can be included without change. Correct?

-- 
MST