diff options
| -rw-r--r-- | Documentation/sound/kernel-api/writing-an-alsa-driver.rst | 14 | ||||
| -rw-r--r-- | sound/core/memalloc.c | 11 |
2 files changed, 16 insertions, 9 deletions
diff --git a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst b/Documentation/sound/kernel-api/writing-an-alsa-driver.rst index 132f5eb9b530..5385618fd881 100644 --- a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst +++ b/Documentation/sound/kernel-api/writing-an-alsa-driver.rst @@ -3523,12 +3523,14 @@ The second argument (type) and the third argument (device pointer) are dependent on the bus. For normal devices, pass the device pointer (typically identical as ``card->dev``) to the third argument with ``SNDRV_DMA_TYPE_DEV`` type. For the continuous buffer unrelated to the -bus can be pre-allocated with ``SNDRV_DMA_TYPE_CONTINUOUS`` type and the -``snd_dma_continuous_data(GFP_KERNEL)`` device pointer, where -``GFP_KERNEL`` is the kernel allocation flag to use. For the -scatter-gather buffers, use ``SNDRV_DMA_TYPE_DEV_SG`` with the device -pointer (see the `Non-Contiguous Buffers`_ -section). +bus can be pre-allocated with ``SNDRV_DMA_TYPE_CONTINUOUS`` type. +You can pass NULL to the device pointer in that case, which is the +default mode implying to allocate with ``GFP_KRENEL`` flag. +If you need a different GFP flag, you can pass it by encoding the flag +into the device pointer via a special macro +:c:func:`snd_dma_continuous_data()`. +For the scatter-gather buffers, use ``SNDRV_DMA_TYPE_DEV_SG`` with the +device pointer (see the `Non-Contiguous Buffers`_ section). Once the buffer is pre-allocated, you can use the allocator in the ``hw_params`` callback: diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c index 6850d13aa98c..1b1c7620cbda 100644 --- a/sound/core/memalloc.c +++ b/sound/core/memalloc.c @@ -99,6 +99,13 @@ static void snd_free_dev_iram(struct snd_dma_buffer *dmab) * */ +static inline gfp_t snd_mem_get_gfp_flags(const struct device *dev) +{ + if (!dev) + return GFP_KERNEL; + else + return (__force gfp_t)(unsigned long)dev; +} /** * snd_dma_alloc_pages - allocate the buffer area according to the given type @@ -120,8 +127,6 @@ int snd_dma_alloc_pages(int type, struct device *device, size_t size, return -ENXIO; if (WARN_ON(!dmab)) return -ENXIO; - if (WARN_ON(!device)) - return -EINVAL; dmab->dev.type = type; dmab->dev.dev = device; @@ -129,7 +134,7 @@ int snd_dma_alloc_pages(int type, struct device *device, size_t size, switch (type) { case SNDRV_DMA_TYPE_CONTINUOUS: dmab->area = alloc_pages_exact(size, - (__force gfp_t)(unsigned long)device); + snd_mem_get_gfp_flags(device)); dmab->addr = 0; break; #ifdef CONFIG_HAS_DMA |