Simplifies allocations by using a flexible array member in this struct.

Remove hsu_dma_alloc_desc. It now offers no readability advantages in
this single usage.

Add __counted_by to get extra runtime analysis.

Apply the exact same treatment to struct hsu_dma and devm_kzalloc.

Signed-off-by: Rosen Penev <[email protected]>
---
 drivers/dma/hsu/hsu.c | 37 ++++++++-----------------------------
 drivers/dma/hsu/hsu.h |  4 ++--
 2 files changed, 10 insertions(+), 31 deletions(-)

diff --git a/drivers/dma/hsu/hsu.c b/drivers/dma/hsu/hsu.c
index f62d60d7bc6b..150c6567eede 100644
--- a/drivers/dma/hsu/hsu.c
+++ b/drivers/dma/hsu/hsu.c
@@ -241,28 +241,10 @@ int hsu_dma_do_irq(struct hsu_dma_chip *chip, unsigned 
short nr, u32 status)
 }
 EXPORT_SYMBOL_GPL(hsu_dma_do_irq);
 
-static struct hsu_dma_desc *hsu_dma_alloc_desc(unsigned int nents)
-{
-       struct hsu_dma_desc *desc;
-
-       desc = kzalloc_obj(*desc, GFP_NOWAIT);
-       if (!desc)
-               return NULL;
-
-       desc->sg = kzalloc_objs(*desc->sg, nents, GFP_NOWAIT);
-       if (!desc->sg) {
-               kfree(desc);
-               return NULL;
-       }
-
-       return desc;
-}
-
 static void hsu_dma_desc_free(struct virt_dma_desc *vdesc)
 {
        struct hsu_dma_desc *desc = to_hsu_dma_desc(vdesc);
 
-       kfree(desc->sg);
        kfree(desc);
 }
 
@@ -276,10 +258,12 @@ static struct dma_async_tx_descriptor 
*hsu_dma_prep_slave_sg(
        struct scatterlist *sg;
        unsigned int i;
 
-       desc = hsu_dma_alloc_desc(sg_len);
+       desc = kzalloc_flex(*desc, sg, sg_len, GFP_NOWAIT);
        if (!desc)
                return NULL;
 
+       desc->nents = sg_len;
+
        for_each_sg(sgl, sg, sg_len, i) {
                desc->sg[i].addr = sg_dma_address(sg);
                desc->sg[i].len = sg_dma_len(sg);
@@ -287,7 +271,6 @@ static struct dma_async_tx_descriptor 
*hsu_dma_prep_slave_sg(
                desc->length += sg_dma_len(sg);
        }
 
-       desc->nents = sg_len;
        desc->direction = direction;
        /* desc->active = 0 by kzalloc */
        desc->status = DMA_IN_PROGRESS;
@@ -430,21 +413,17 @@ int hsu_dma_probe(struct hsu_dma_chip *chip)
        void __iomem *addr = chip->regs + chip->offset;
        unsigned short i;
        int ret;
+       unsigned short nr_channels;
 
-       hsu = devm_kzalloc(chip->dev, sizeof(*hsu), GFP_KERNEL);
+       /* Calculate nr_channels from the IO space length */
+       nr_channels = (chip->length - chip->offset) / HSU_DMA_CHAN_LENGTH;
+       hsu = devm_kzalloc(chip->dev, struct_size(hsu, chan, nr_channels), 
GFP_KERNEL);
        if (!hsu)
                return -ENOMEM;
 
+       hsu->nr_channels = nr_channels;
        chip->hsu = hsu;
 
-       /* Calculate nr_channels from the IO space length */
-       hsu->nr_channels = (chip->length - chip->offset) / HSU_DMA_CHAN_LENGTH;
-
-       hsu->chan = devm_kcalloc(chip->dev, hsu->nr_channels,
-                                sizeof(*hsu->chan), GFP_KERNEL);
-       if (!hsu->chan)
-               return -ENOMEM;
-
        INIT_LIST_HEAD(&hsu->dma.channels);
        for (i = 0; i < hsu->nr_channels; i++) {
                struct hsu_dma_chan *hsuc = &hsu->chan[i];
diff --git a/drivers/dma/hsu/hsu.h b/drivers/dma/hsu/hsu.h
index 3bca577b98a1..f6ca1014bccf 100644
--- a/drivers/dma/hsu/hsu.h
+++ b/drivers/dma/hsu/hsu.h
@@ -71,11 +71,11 @@ struct hsu_dma_sg {
 struct hsu_dma_desc {
        struct virt_dma_desc vdesc;
        enum dma_transfer_direction direction;
-       struct hsu_dma_sg *sg;
        unsigned int nents;
        size_t length;
        unsigned int active;
        enum dma_status status;
+       struct hsu_dma_sg sg[] __counted_by(nents);
 };
 
 static inline struct hsu_dma_desc *to_hsu_dma_desc(struct virt_dma_desc *vdesc)
@@ -115,8 +115,8 @@ struct hsu_dma {
        struct dma_device               dma;
 
        /* channels */
-       struct hsu_dma_chan             *chan;
        unsigned short                  nr_channels;
+       struct hsu_dma_chan             chan[] __counted_by(nr_channels);
 };
 
 static inline struct hsu_dma *to_hsu_dma(struct dma_device *ddev)
-- 
2.53.0


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