[RFC PATCH v2 02/10] dma/pool: Add an API to check if DMA allocation is from pool

DMA allocations can be done through DMA pools, add an API that can be
used to check if an allocation is done from a pool. This will be used in
the later commit during preservation of DMA allocation.

Signed-off-by: Samiullah Khawaja <[email protected]>
---
 include/linux/dma-map-ops.h |  1 +
 kernel/dma/pool.c           | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 6a1832a73cad..9382785a2faa 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -216,6 +216,7 @@ struct page *dma_alloc_from_pool(struct device *dev, size_t size,
 		bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t));
 bool dma_free_from_pool(struct device *dev, void *start, size_t size);
 
+bool dma_is_from_pool(void *start, size_t size);
 int dma_direct_set_offset(struct device *dev, phys_addr_t cpu_start,
 		dma_addr_t dma_start, u64 size);
 
diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index 2b2fbb709242..d1a0bb03e478 100644
--- a/kernel/dma/pool.c
+++ b/kernel/dma/pool.c
@@ -307,3 +307,16 @@ bool dma_free_from_pool(struct device *dev, void *start, size_t size)
 
 	return false;
 }
+
+bool dma_is_from_pool(void *start, size_t size)
+{
+	struct gen_pool *pool = NULL;
+
+	while ((pool = dma_guess_pool(pool, 0))) {
+		if (!gen_pool_has_addr(pool, (unsigned long)start, size))
+			continue;
+		return true;
+	}
+
+	return false;
+}
-- 
2.55.0.795.g602f6c329a-goog