[PATCH v10 2/5] genalloc:support allocating specific region

Zhao Qiang
2015-09-18T07:21:32Z

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.
Changes for v10:
- rename gen_pool_fixed_fit to gen_pool_fixed_alloc

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..56d5d96 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_alloc.
+ */
+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_alloc(unsigned long *map,
+ unsigned long size, unsigned long start, unsigned int nr,
+ void *data, struct gen_pool *pool);
+
extern unsigned long gen_pool_first_fit_align(unsigned long *map,
unsigned long size, unsigned long start, unsigned int nr,
void *data, struct gen_pool *pool);
diff --git a/lib/genalloc.c b/lib/genalloc.c
index b8762b1..1e6fde8 100644
--- a/lib/genalloc.c
+++ b/lib/genalloc.c
@@ -554,6 +554,36 @@ unsigned long gen_pool_first_fit_align(unsigned long *map, unsigned long size,
EXPORT_SYMBOL(gen_pool_first_fit_align);

/**
+ * gen_pool_fixed_alloc - 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_alloc(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_alloc);
+
+/**
* gen_pool_first_fit_order_align - find the first available region
* of memory matching the size requirement. The region will be aligned
* to the order of the size specified.
--
2.1.0.27.g96db324