2018/5/6 1:09 Mauro Carvalho Chehab <mchehab+samsung@kernel.org>:

> I can't think on a single reason why this driver would be using
> GFP_DMA. The typical usage is as an USB driver. Any DMA restrictions
> should be handled inside the HCI driver, if any.
>

siano driver supports SDIO (implemented
in drivers/media/mmc/siano/smssdio.c) as well as USB.
It looks like using sdio_memcpy_toio() to DMA transfer. I think that's why
it is using GFP_DMA.


> Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
> Cc: linux-mm@kvack.org
> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
> ---
>  drivers/media/common/siano/smscoreapi.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/media/common/siano/smscoreapi.c
> b/drivers/media/common/siano/smscoreapi.c
> index 1c93258a2d47..a5f0db0810d4 100644
> --- a/drivers/media/common/siano/smscoreapi.c
> +++ b/drivers/media/common/siano/smscoreapi.c
> @@ -697,7 +697,7 @@ int smscore_register_device(struct smsdevice_params_t
> *params,
>                 buffer = dma_alloc_coherent(params->device,
>                                             dev->common_buffer_size,
>                                             &dev->common_buffer_phys,
> -                                           GFP_KERNEL | GFP_DMA);
> +                                           GFP_KERNEL);
>         if (!buffer) {
>                 smscore_unregister_device(dev);
>                 return -ENOMEM;
> @@ -792,7 +792,7 @@ static int smscore_init_ir(struct smscore_device_t
> *coredev)
>                 else {
>                         buffer = kmalloc(sizeof(struct sms_msg_data2) +
>                                                 SMS_DMA_ALIGNMENT,
> -                                               GFP_KERNEL | GFP_DMA);
> +                                               GFP_KERNEL);
>                         if (buffer) {
>                                 struct sms_msg_data2 *msg =
>                                 (struct sms_msg_data2 *)
> @@ -933,7 +933,7 @@ static int smscore_load_firmware_family2(struct
> smscore_device_t *coredev,
>         }
>
>         /* PAGE_SIZE buffer shall be enough and dma aligned */
> -       msg = kmalloc(PAGE_SIZE, GFP_KERNEL | GFP_DMA);
> +       msg = kmalloc(PAGE_SIZE, GFP_KERNEL);
>         if (!msg)
>                 return -ENOMEM;
>
> @@ -1168,7 +1168,7 @@ static int smscore_load_firmware_from_file(struct
> smscore_device_t *coredev,
>         }
>         pr_debug("read fw %s, buffer size=0x%zx\n", fw_filename, fw->size);
>         fw_buf = kmalloc(ALIGN(fw->size + sizeof(struct sms_firmware),
> -                        SMS_ALLOC_ALIGNMENT), GFP_KERNEL | GFP_DMA);
> +                        SMS_ALLOC_ALIGNMENT), GFP_KERNEL);
>         if (!fw_buf) {
>                 pr_err("failed to allocate firmware buffer\n");
>                 rc = -ENOMEM;
> @@ -1260,7 +1260,7 @@ EXPORT_SYMBOL_GPL(smscore_unregister_device);
>  static int smscore_detect_mode(struct smscore_device_t *coredev)
>  {
>         void *buffer = kmalloc(sizeof(struct sms_msg_hdr) +
> SMS_DMA_ALIGNMENT,
> -                              GFP_KERNEL | GFP_DMA);
> +                              GFP_KERNEL);
>         struct sms_msg_hdr *msg =
>                 (struct sms_msg_hdr *) SMS_ALIGN_ADDRESS(buffer);
>         int rc;
> @@ -1309,7 +1309,7 @@ static int smscore_init_device(struct
> smscore_device_t *coredev, int mode)
>         int rc = 0;
>
>         buffer = kmalloc(sizeof(struct sms_msg_data) +
> -                       SMS_DMA_ALIGNMENT, GFP_KERNEL | GFP_DMA);
> +                       SMS_DMA_ALIGNMENT, GFP_KERNEL);
>         if (!buffer)
>                 return -ENOMEM;
>
> @@ -1398,7 +1398,7 @@ int smscore_set_device_mode(struct smscore_device_t
> *coredev, int mode)
>                 coredev->device_flags &= ~SMS_DEVICE_NOT_READY;
>
>                 buffer = kmalloc(sizeof(struct sms_msg_data) +
> -                                SMS_DMA_ALIGNMENT, GFP_KERNEL | GFP_DMA);
> +                                SMS_DMA_ALIGNMENT, GFP_KERNEL);
>                 if (buffer) {
>                         struct sms_msg_data *msg = (struct sms_msg_data *)
> SMS_ALIGN_ADDRESS(buffer);
>
> @@ -1971,7 +1971,7 @@ int smscore_gpio_configure(struct smscore_device_t
> *coredev, u8 pin_num,
>         total_len = sizeof(struct sms_msg_hdr) + (sizeof(u32) * 6);
>
>         buffer = kmalloc(total_len + SMS_DMA_ALIGNMENT,
> -                       GFP_KERNEL | GFP_DMA);
> +                       GFP_KERNEL);
>         if (!buffer)
>                 return -ENOMEM;
>
> @@ -2043,7 +2043,7 @@ int smscore_gpio_set_level(struct smscore_device_t
> *coredev, u8 pin_num,
>                         (3 * sizeof(u32)); /* keep it 3 ! */
>
>         buffer = kmalloc(total_len + SMS_DMA_ALIGNMENT,
> -                       GFP_KERNEL | GFP_DMA);
> +                       GFP_KERNEL);
>         if (!buffer)
>                 return -ENOMEM;
>
> @@ -2091,7 +2091,7 @@ int smscore_gpio_get_level(struct smscore_device_t
> *coredev, u8 pin_num,
>         total_len = sizeof(struct sms_msg_hdr) + (2 * sizeof(u32));
>
>         buffer = kmalloc(total_len + SMS_DMA_ALIGNMENT,
> -                       GFP_KERNEL | GFP_DMA);
> +                       GFP_KERNEL);
>         if (!buffer)
>                 return -ENOMEM;
>
> --
> 2.17.0
>
>