One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct foo {
int stuff;
struct boo entry[];
};
size = sizeof(struct foo) + count * sizeof(struct boo);
instance = kzalloc(size, GFP_KERNEL)
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
size = struct_size(instance, entry, count);
or
instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL)
Based on the above, replace gdma_dma_alloc_desc() with kzalloc() and
use the new struct_size() helper.
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
---
drivers/staging/ralink-gdma/ralink-gdma.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/drivers/staging/ralink-gdma/ralink-gdma.c b/drivers/staging/ralink-gdma/ralink-gdma.c
index b6d484532269..3228227776dc 100644
--- a/drivers/staging/ralink-gdma/ralink-gdma.c
+++ b/drivers/staging/ralink-gdma/ralink-gdma.c
@@ -169,12 +169,6 @@ static inline void gdma_dma_write(struct gdma_dma_dev *dma_dev,
writel(val, dma_dev->base + reg);
}
-static struct gdma_dma_desc *gdma_dma_alloc_desc(unsigned int num_sgs)
-{
- return kzalloc(sizeof(struct gdma_dma_desc) +
- sizeof(struct gdma_dma_sg) * num_sgs, GFP_ATOMIC);
-}
-
static enum gdma_dma_transfer_size gdma_dma_maxburst(u32 maxburst)
{
if (maxburst < 2)
@@ -531,7 +525,7 @@ static struct dma_async_tx_descriptor *gdma_dma_prep_slave_sg(
struct scatterlist *sg;
unsigned int i;
- desc = gdma_dma_alloc_desc(sg_len);
+ desc = kzalloc(struct_size(desc, sg, sg_len), GFP_ATOMIC);
if (!desc) {
dev_err(c->device->dev, "alloc sg decs error\n");
return NULL;
@@ -586,7 +580,7 @@ static struct dma_async_tx_descriptor *gdma_dma_prep_dma_memcpy(
xfer_count = GDMA_REG_CTRL0_TX_MASK;
num_periods = DIV_ROUND_UP(len, xfer_count);
- desc = gdma_dma_alloc_desc(num_periods);
+ desc = kzalloc(struct_size(desc, sg, num_periods), GFP_ATOMIC);
if (!desc) {
dev_err(c->device->dev, "alloc memcpy decs error\n");
return NULL;
@@ -631,7 +625,7 @@ static struct dma_async_tx_descriptor *gdma_dma_prep_dma_cyclic(
}
num_periods = buf_len / period_len;
- desc = gdma_dma_alloc_desc(num_periods);
+ desc = kzalloc(struct_size(desc, sg, num_periods), GFP_ATOMIC);
if (!desc) {
dev_err(c->device->dev, "alloc cyclic decs error\n");
return NULL;
--
2.21.0
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