[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@xxxxxxxxx>
---
 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