[PATCH] HID: Intel-thc-hid: Intel-thc: fix dma_unmap_sg() nents value

[PATCH] HID: Intel-thc-hid: Intel-thc: fix dma_unmap_sg() nents value

[Thomas Fourier]

The `dma_unmap_sg()` functions should be called with the same nents as the
`dma_map_sg()`, not the value the map function returned.

Save the number of entries in struct thc_dma_configuration.

Fixes: a688404b2e20 ("HID: intel-thc-hid: intel-thc: Add THC DMA interfaces")
Signed-off-by: Thomas Fourier <fourier.thomas@gmail.com>
---
 drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c | 4 +++-
 drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.h | 2 ++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c
index 82b8854843e0..a0c368aa7979 100644
--- a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c
+++ b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c
@@ -232,6 +232,7 @@ static int setup_dma_buffers(struct thc_device *dev,
 		return 0;
 
 	memset(config->sgls, 0, sizeof(config->sgls));
+	memset(config->sgls_nent_pages, 0, sizeof(config->sgls_nent_pages));
 	memset(config->sgls_nent, 0, sizeof(config->sgls_nent));
 
 	cpu_addr = dma_alloc_coherent(dev->dev, prd_tbls_size,
@@ -254,6 +255,7 @@ static int setup_dma_buffers(struct thc_device *dev,
 		}
 		count = dma_map_sg(dev->dev, config->sgls[i], nent, dir);
 
+		config->sgls_nent_pages[i] = nent;
 		config->sgls_nent[i] = count;
 	}
 
@@ -299,7 +301,7 @@ static void release_dma_buffers(struct thc_device *dev,
 			continue;
 
 		dma_unmap_sg(dev->dev, config->sgls[i],
-			     config->sgls_nent[i],
+			     config->sgls_nent_pages[i],
 			     config->dir);
 
 		sgl_free(config->sgls[i]);
diff --git a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.h b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.h
index 78917400492c..541d33995baf 100644
--- a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.h
+++ b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.h
@@ -91,6 +91,7 @@ struct thc_prd_table {
  * @dir: Direction of DMA for this config
  * @prd_tbls: PRD tables for current DMA
  * @sgls: Array of pointers to scatter-gather lists
+ * @sgls_nent_pages: Number of pages per scatter-gather list
  * @sgls_nent: Actual number of entries per scatter-gather list
  * @prd_tbl_num: Actual number of PRD tables
  * @max_packet_size: Size of the buffer needed for 1 DMA message (1 PRD table)
@@ -107,6 +108,7 @@ struct thc_dma_configuration {
 
 	struct thc_prd_table *prd_tbls;
 	struct scatterlist *sgls[PRD_TABLES_NUM];
+	u8 sgls_nent_pages[PRD_TABLES_NUM];
 	u8 sgls_nent[PRD_TABLES_NUM];
 	u8 prd_tbl_num;
 
-- 
2.43.0

Re: [PATCH] HID: Intel-thc-hid: Intel-thc: fix dma_unmap_sg() nents value

[Andy Shevchenko]

On Wed, Dec 03, 2025 at 05:56:35PM +0100, Thomas Fourier wrote:
> The `dma_unmap_sg()` functions should be called with the same nents as the
> `dma_map_sg()`, not the value the map function returned.
> 
> Save the number of entries in struct thc_dma_configuration.

Your email has an empty To:. Some spamfilters may be triggered by this.
I recommend to use `b4` tool to handle the patches.

The change LGTM,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

-- 
With Best Regards,
Andy Shevchenko

RE: [PATCH] HID: Intel-thc-hid: Intel-thc: fix dma_unmap_sg() nents value

[Xu, Even]

> -----Original Message-----
> From: Thomas Fourier <fourier.thomas@gmail.com>
> Sent: Thursday, December 4, 2025 12:57 AM
> Cc: Thomas Fourier <fourier.thomas@gmail.com>; Xu, Even
> <even.xu@intel.com>; Sun, Xinpeng <xinpeng.sun@intel.com>; Jiri Kosina
> <jikos@kernel.org>; Benjamin Tissoires <bentiss@kernel.org>; Andy Shevchenko
> <andriy.shevchenko@linux.intel.com>; Mark Pearson <mpearson-
> lenovo@squebb.ca>; Srinivas Pandruvada
> <srinivas.pandruvada@linux.intel.com>; linux-input@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Subject: [PATCH] HID: Intel-thc-hid: Intel-thc: fix dma_unmap_sg() nents value
> 
> The `dma_unmap_sg()` functions should be called with the same nents as the
> `dma_map_sg()`, not the value the map function returned.
> 
> Save the number of entries in struct thc_dma_configuration.
> 
> Fixes: a688404b2e20 ("HID: intel-thc-hid: intel-thc: Add THC DMA interfaces")
> Signed-off-by: Thomas Fourier <fourier.thomas@gmail.com>

Thanks for the fix!
Looks good to me.

Reviewed-by: Even Xu <even.xu@intel.com>

> ---
>  drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c | 4 +++-  drivers/hid/intel-thc-
> hid/intel-thc/intel-thc-dma.h | 2 ++
>  2 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c b/drivers/hid/intel-
> thc-hid/intel-thc/intel-thc-dma.c
> index 82b8854843e0..a0c368aa7979 100644
> --- a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c
> +++ b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c
> @@ -232,6 +232,7 @@ static int setup_dma_buffers(struct thc_device *dev,
>  		return 0;
> 
>  	memset(config->sgls, 0, sizeof(config->sgls));
> +	memset(config->sgls_nent_pages, 0, sizeof(config->sgls_nent_pages));
>  	memset(config->sgls_nent, 0, sizeof(config->sgls_nent));
> 
>  	cpu_addr = dma_alloc_coherent(dev->dev, prd_tbls_size, @@ -254,6
> +255,7 @@ static int setup_dma_buffers(struct thc_device *dev,
>  		}
>  		count = dma_map_sg(dev->dev, config->sgls[i], nent, dir);
> 
> +		config->sgls_nent_pages[i] = nent;
>  		config->sgls_nent[i] = count;
>  	}
> 
> @@ -299,7 +301,7 @@ static void release_dma_buffers(struct thc_device *dev,
>  			continue;
> 
>  		dma_unmap_sg(dev->dev, config->sgls[i],
> -			     config->sgls_nent[i],
> +			     config->sgls_nent_pages[i],
>  			     config->dir);
> 
>  		sgl_free(config->sgls[i]);
> diff --git a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.h b/drivers/hid/intel-
> thc-hid/intel-thc/intel-thc-dma.h
> index 78917400492c..541d33995baf 100644
> --- a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.h
> +++ b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.h
> @@ -91,6 +91,7 @@ struct thc_prd_table {
>   * @dir: Direction of DMA for this config
>   * @prd_tbls: PRD tables for current DMA
>   * @sgls: Array of pointers to scatter-gather lists
> + * @sgls_nent_pages: Number of pages per scatter-gather list
>   * @sgls_nent: Actual number of entries per scatter-gather list
>   * @prd_tbl_num: Actual number of PRD tables
>   * @max_packet_size: Size of the buffer needed for 1 DMA message (1 PRD
> table) @@ -107,6 +108,7 @@ struct thc_dma_configuration {
> 
>  	struct thc_prd_table *prd_tbls;
>  	struct scatterlist *sgls[PRD_TABLES_NUM];
> +	u8 sgls_nent_pages[PRD_TABLES_NUM];
>  	u8 sgls_nent[PRD_TABLES_NUM];
>  	u8 prd_tbl_num;
> 
> --
> 2.43.0

Re: [PATCH] HID: Intel-thc-hid: Intel-thc: fix dma_unmap_sg() nents value

[Benjamin Tissoires]

On Wed, 03 Dec 2025 17:56:35 +0100, Thomas Fourier wrote:
> The `dma_unmap_sg()` functions should be called with the same nents as the
> `dma_map_sg()`, not the value the map function returned.
> 
> Save the number of entries in struct thc_dma_configuration.
> 
> 

Applied to hid/hid.git (for-6.19/upstream-fixes), thanks!

[1/1] HID: Intel-thc-hid: Intel-thc: fix dma_unmap_sg() nents value
      https://git.kernel.org/hid/hid/c/0e13150c1a13

Cheers,
-- 
Benjamin Tissoires <bentiss@kernel.org>