[PATCHv3 2/5] lib/genalloc.c: Add genpool range check function

Laura Abbott
2014-06-17T01:39:36Z

After allocating an address from a particular genpool,
there is no good way to verify if that address actually
belongs to a genpool. Introduce addr_in_gen_pool which
will return if an address plus size falls completely
within the genpool range.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
---
include/linux/genalloc.h | 3 +++
lib/genalloc.c | 29 +++++++++++++++++++++++++++++
2 files changed, 32 insertions(+)

diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h
index 3cd0934..1ccaab4 100644
--- a/include/linux/genalloc.h
+++ b/include/linux/genalloc.h
@@ -121,6 +121,9 @@ extern struct gen_pool *devm_gen_pool_create(struct device *dev,
int min_alloc_order, int nid);
extern struct gen_pool *dev_get_gen_pool(struct device *dev);

+bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start,
+ size_t size);
+
#ifdef CONFIG_OF
extern struct gen_pool *of_get_named_gen_pool(struct device_node *np,
const char *propname, int index);
diff --git a/lib/genalloc.c b/lib/genalloc.c
index 9758529..66edf93 100644
--- a/lib/genalloc.c
+++ b/lib/genalloc.c
@@ -403,6 +403,35 @@ void gen_pool_for_each_chunk(struct gen_pool *pool,
EXPORT_SYMBOL(gen_pool_for_each_chunk);

/**
+ * addr_in_gen_pool - checks if an address falls within the range of a pool
+ * @pool: the generic memory pool
+ * @start: start address
+ * @size: size of the region
+ *
+ * Check if the range of addresses falls within the specified pool. Takes
+ * the rcu_read_lock for the duration of the check.
+ */
+bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start,
+ size_t size)
+{
+ bool found = false;
+ unsigned long end = start + size;
+ struct gen_pool_chunk *chunk;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk) {
+ if (start >= chunk->start_addr && start <= chunk->end_addr) {
+ if (end <= chunk->end_addr) {
+ found = true;
+ break;
+ }
+ }
+ }
+ rcu_read_unlock();
+ return found;
+}
+
+/**
* gen_pool_avail - get available free space of the pool
* @pool: pool to get available free space
*