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SubjectRe: [PATCH v9 2/5] genalloc:support allocating specific region
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On Mon, 2015-09-14 at 09:38 +0800, Zhao Qiang wrote:
> Add new algo for genalloc, it reserve a specific region of
> memory matching the size requirement (no alignment constraint)
>
> Signed-off-by: Zhao Qiang <qiang.zhao@freescale.com>
> ---
> Changes for v9:
> - reserve a specific region, if the return region
> - is not during the specific region, return fail.
>
> include/linux/genalloc.h | 11 +++++++++++
> lib/genalloc.c | 30 ++++++++++++++++++++++++++++++
> 2 files changed, 41 insertions(+)
>
> diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h
> index aaf3dc2..85e3b2f 100644
> --- a/include/linux/genalloc.h
> +++ b/include/linux/genalloc.h
> @@ -82,6 +82,13 @@ struct genpool_data_align {
> int align; /* alignment by bytes for starting address */
> };
>
> +/*
> + * gen_pool data descriptor for gen_pool_fixed_fit.
> + */
> +struct genpool_data_fixed {
> + unsigned long offset; /* The offset of the specific region */
> +};
> +
> extern struct gen_pool *gen_pool_create(int, int);
> extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned
> long);
> extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t,
> @@ -121,6 +128,10 @@ extern unsigned long gen_pool_first_fit(unsigned long
> *map, unsigned long size,
> unsigned long start, unsigned int nr, void *data,
> struct gen_pool *pool);
>
> +extern unsigned long gen_pool_fixed_fit(unsigned long *map,
> + unsigned long size, unsigned long start, unsigned int nr,
> + void *data, struct gen_pool *pool);
> +

"fixed fit" doesn't make much sense... How about "fixed_alloc"?

/**
> + * gen_pool_fixed_fit - reserve a specific region of
> + * matching the size requirement (no alignment constraint)
> + * @map: The address to base the search on
> + * @size: The bitmap size in bits
> + * @start: The bitnumber to start searching at
> + * @nr: The number of zeroed bits we're looking for
> + * @data: data for alignment
> + * @pool: pool to get order from
> + */
> +unsigned long gen_pool_fixed_fit(unsigned long *map, unsigned long size,
> + unsigned long start, unsigned int nr, void *data,
> + struct gen_pool *pool)
> +{
> + struct genpool_data_fixed *fixed_data;
> + int order;
> + unsigned long offset_bit;
> + unsigned long start_bit;
> +
> + fixed_data = data;
> + order = pool->min_alloc_order;
> + offset_bit = fixed_data->offset >> order;
> + start_bit = bitmap_find_next_zero_area(map, size,
> + start + offset_bit, nr, 0);
> + if (start_bit != offset_bit)
> + start_bit = size;
> + return start_bit;
> +}
> +EXPORT_SYMBOL(gen_pool_fixed_fit);

This would be simpler with bitmap_allocate_region().

-Scott



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