On 3/21/2025 7:33 AM, Dan Carpenter wrote:
On Wed, Mar 19, 2025 at 02:32:36PM -0700, Shannon Nelson wrote:
+static struct pds_fwctl_query_data *pdsfc_get_endpoints(struct pdsfc_dev *pdsfc,
+ dma_addr_t *pa)
+{
+ struct device *dev = &pdsfc->fwctl.dev;
+ union pds_core_adminq_comp comp = {0};
+ struct pds_fwctl_query_data *data;
+ union pds_core_adminq_cmd cmd;
+ dma_addr_t data_pa;
+ int err;
+
+ data = dma_alloc_coherent(dev->parent, PAGE_SIZE, &data_pa, GFP_KERNEL);
+ err = dma_mapping_error(dev, data_pa);
+ if (err) {
+ dev_err(dev, "Failed to map endpoint list\n");
+ return ERR_PTR(err);
+ }
This doesn't work. The dma_alloc_coherent() function doesn't necessarily
initialize data_pa. I don't know very much about DMA but can't we just
check:
data = dma_alloc_coherent(dev->parent, PAGE_SIZE, &data_pa, GFP_KERNEL);
if (!data)
return ERR_PTR(-ENOMEM);
regards,
dan carpenter
Yes, you are right. This works for the dma_map_single() calls on
already allocated blocks, but not here for the alloc-and-map calls. I
think something like this would be better:
Author: Shannon Nelson <shannon.nelson@xxxxxxx>
Date: Fri Mar 21 09:37:52 2025 -0700
pds_fwctl: fix use of dma_mapping_error()
The dma_alloc_coherent() call only returns NULL if there is an
error, so checking the dma_handle with dma_mapping_error() is
not useful. Fix this by checking the returned address for NULL.
Signed-off-by: Shannon Nelson <shannon.nelson@xxxxxxx>
diff --git a/drivers/fwctl/pds/main.c b/drivers/fwctl/pds/main.c
index 6fedde2a962e..e50e1bbdff9a 100644
--- a/drivers/fwctl/pds/main.c
+++ b/drivers/fwctl/pds/main.c
@@ -76,8 +76,7 @@ static int pdsfc_identify(struct pdsfc_dev *pdsfc)
int err;
ident = dma_alloc_coherent(dev->parent, sizeof(*ident),
&ident_pa, GFP_KERNEL);
- err = dma_mapping_error(dev->parent, ident_pa);
- if (err) {
+ if (!ident) {
dev_err(dev, "Failed to map ident buffer\n");
return err;
}
@@ -151,8 +150,7 @@ static struct pds_fwctl_query_data
*pdsfc_get_endpoints(struct pdsfc_dev *pdsfc,
int err;
data = dma_alloc_coherent(dev->parent, PAGE_SIZE, &data_pa,
GFP_KERNEL);
- err = dma_mapping_error(dev, data_pa);
- if (err) {
+ if (!data) {
dev_err(dev, "Failed to map endpoint list\n");
return ERR_PTR(err);
}
@@ -221,8 +219,7 @@ static struct pds_fwctl_query_data
*pdsfc_get_operations(struct pdsfc_dev *pdsfc
/* Query the operations list for the given endpoint */
data = dma_alloc_coherent(dev->parent, PAGE_SIZE, &data_pa,
GFP_KERNEL);
- err = dma_mapping_error(dev->parent, data_pa);
- if (err) {
+ if (!data) {
dev_err(dev, "Failed to map operations list\n");
return ERR_PTR(err);
}
