[PATCHv2] dmaengine: dw-axi-dmac: simplify allocation

Rosen Penev
2026-04-06T19:44:44Z

Use a flexible array member with kzalloc_flex() to combine allocations.

Add __counted_by for extra runtime analysis.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
v2: use () for kzalloc_flex in description.
drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c | 8 +-------
drivers/dma/dw-axi-dmac/dw-axi-dmac.h | 4 ++--
2 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
index 4d53f077e9d2..d3ca202dc478 100644
--- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
+++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
@@ -294,15 +294,10 @@ static struct axi_dma_desc *axi_desc_alloc(u32 num)
{
struct axi_dma_desc *desc;

- desc = kzalloc_obj(*desc, GFP_NOWAIT);
+ desc = kzalloc_flex(*desc, hw_desc, num, GFP_NOWAIT);
if (!desc)
return NULL;

- desc->hw_desc = kzalloc_objs(*desc->hw_desc, num, GFP_NOWAIT);
- if (!desc->hw_desc) {
- kfree(desc);
- return NULL;
- }
desc->nr_hw_descs = num;

return desc;
@@ -339,7 +334,6 @@ static void axi_desc_put(struct axi_dma_desc *desc)
dma_pool_free(chan->desc_pool, hw_desc->lli, hw_desc->llp);
}

- kfree(desc->hw_desc);
kfree(desc);
atomic_sub(descs_put, &chan->descs_allocated);
dev_vdbg(chan2dev(chan), "%s: %d descs put, %d still allocated\n",
diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
index 67cc199e24d1..a04a4e03eb3d 100644
--- a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
+++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
@@ -98,14 +98,14 @@ struct axi_dma_hw_desc {
};

struct axi_dma_desc {
- struct axi_dma_hw_desc *hw_desc;
-
struct virt_dma_desc vd;
struct axi_dma_chan *chan;
u32 completed_blocks;
u32 length;
u32 period_len;
u32 nr_hw_descs;
+
+ struct axi_dma_hw_desc hw_desc[] __counted_by(nr_hw_descs);
};

struct axi_dma_chan_config {
--
2.53.0