2017-09-15 15:08:48

by Arnd Bergmann

Subject: [PATCH] dma-coherent: fix rmem_dma_device_init regression

My recent bug fix introduced another bug, which caused rmem_dma_device_init
to always fail, as rmem->priv is never set to anything.

This restores the previous behavior, calling dma_init_coherent_memory()
whenever ->priv is NULL.

Fixes: d35b0996fef3 ("dma-coherent: fix dma_declare_coherent_memory() logic error")
Reported-by: Roy Pledge <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
---
Roy, can you test this new fix?
---
drivers/base/dma-coherent.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c
index a39b2166b145..744f64f43454 100644
--- a/drivers/base/dma-coherent.c
+++ b/drivers/base/dma-coherent.c
@@ -348,16 +348,15 @@ static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
struct dma_coherent_mem *mem = rmem->priv;
int ret;

- if (!mem)
- return -ENODEV;
-
- ret = dma_init_coherent_memory(rmem->base, rmem->base, rmem->size,
- DMA_MEMORY_EXCLUSIVE, &mem);
-
- if (ret) {
- pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
- &rmem->base, (unsigned long)rmem->size / SZ_1M);
- return ret;
+ if (!mem) {
+ ret = dma_init_coherent_memory(rmem->base, rmem->base,
+ rmem->size,
+ DMA_MEMORY_EXCLUSIVE, &mem);
+ if (ret) {
+ pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
+ &rmem->base, (unsigned long)rmem->size / SZ_1M);
+ return ret;
+ }
}
mem->use_dev_dma_pfn_offset = true;
rmem->priv = mem;
--
2.9.0

2017-09-17 12:35:06

by Roy Pledge

Subject: Re: [PATCH] dma-coherent: fix rmem_dma_device_init regression

On 9/15/2017 11:08 AM, Arnd Bergmann wrote:
> My recent bug fix introduced another bug, which caused rmem_dma_device_init
> to always fail, as rmem->priv is never set to anything.
>
> This restores the previous behavior, calling dma_init_coherent_memory()
> whenever ->priv is NULL.
>
> Fixes: d35b0996fef3 ("dma-coherent: fix dma_declare_coherent_memory() logic error")
> Reported-by: Roy Pledge <[email protected]>
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> Roy, can you test this new fix?
> ---
> drivers/base/dma-coherent.c | 19 +++++++++----------
> 1 file changed, 9 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c
> index a39b2166b145..744f64f43454 100644
> --- a/drivers/base/dma-coherent.c
> +++ b/drivers/base/dma-coherent.c
> @@ -348,16 +348,15 @@ static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
> struct dma_coherent_mem *mem = rmem->priv;
> int ret;
>
> - if (!mem)
> - return -ENODEV;
> -
> - ret = dma_init_coherent_memory(rmem->base, rmem->base, rmem->size,
> - DMA_MEMORY_EXCLUSIVE, &mem);
> -
> - if (ret) {
> - pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
> - &rmem->base, (unsigned long)rmem->size / SZ_1M);
> - return ret;
> + if (!mem) {
> + ret = dma_init_coherent_memory(rmem->base, rmem->base,
> + rmem->size,
> + DMA_MEMORY_EXCLUSIVE, &mem);
> + if (ret) {
> + pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
> + &rmem->base, (unsigned long)rmem->size / SZ_1M);
> + return ret;
> + }
> }
> mem->use_dev_dma_pfn_offset = true;
> rmem->priv = mem;
>
I tried this and it solves the issue I was seeing. Thanks for the quick fix.

Tested-by: Roy Pledge <[email protected]>

2017-09-17 15:20:23

by Christoph Hellwig

Subject: Re: [PATCH] dma-coherent: fix rmem_dma_device_init regression

Thanks a lot Arnd,

applied to the dma-mapping tree for 4.14.