From 39cd652d071184e3bab97ba92f6da30152289905 Mon Sep 17 00:00:00 2001
From: karthikeyan <karthiproffesional@gmail.com>
Date: Sun, 11 Jan 2026 08:36:25 +0200
Subject: [PATCH] usb: dwc2: add missing SLAB_CACHE_DMA flag for
 desc_hsisoc_cache

The desc_hsisoc_cache kmem_cache is used to allocate DMA descriptors
for High-Speed isochronous transfers. These descriptors are passed to
the hardware via dma_map_single() in dwc2_desc_list_alloc().

The desc_gen_cache, which serves the same purpose for other transfer
types, correctly specifies SLAB_CACHE_DMA. However, desc_hsisoc_cache
was created without this flag, despite both caches being used
identically for DMA descriptor allocation.

Add the missing SLAB_CACHE_DMA flag to desc_hsisoc_cache for
consistency and correctness on platforms with DMA zone restrictions.
This also protects against future allocations from this cache that
might omit GFP_DMA.

Fixes: 3b5fcc9ac2f4 ("usb: dwc2: host: use kmem cache to allocate descriptors")
Signed-off-by: karthikeyan <karthiproffesional@gmail.com>
---
 drivers/usb/dwc2/hcd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index 30eb8506617c..556d6ab36930 100644
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -5273,7 +5273,7 @@ int dwc2_hcd_init(struct dwc2_hsotg *hsotg)

                hsotg->desc_hsisoc_cache = kmem_cache_create("dwc2-hsisoc-desc",
                                sizeof(struct dwc2_dma_desc) *
-                               MAX_DMA_DESC_NUM_HS_ISOC, 512, 0, NULL);
+                               MAX_DMA_DESC_NUM_HS_ISOC, 512,
SLAB_CACHE_DMA, NULL);
                if (!hsotg->desc_hsisoc_cache) {
                        dev_err(hsotg->dev,
                                "unable to create dwc2 hs isoc desc cache\n");
--
2.34.1

On Sun, Jan 11, 2026 at 01:01:51PM +0530, karthikeyan K S wrote:
> >From 39cd652d071184e3bab97ba92f6da30152289905 Mon Sep 17 00:00:00 2001
> From: karthikeyan <karthiproffesional@gmail.com>
> Date: Sun, 11 Jan 2026 08:36:25 +0200
> Subject: [PATCH] usb: dwc2: add missing SLAB_CACHE_DMA flag for
>  desc_hsisoc_cache
> 
> The desc_hsisoc_cache kmem_cache is used to allocate DMA descriptors
> for High-Speed isochronous transfers. These descriptors are passed to
> the hardware via dma_map_single() in dwc2_desc_list_alloc().
> 
> The desc_gen_cache, which serves the same purpose for other transfer
> types, correctly specifies SLAB_CACHE_DMA. However, desc_hsisoc_cache
> was created without this flag, despite both caches being used
> identically for DMA descriptor allocation.
> 
> Add the missing SLAB_CACHE_DMA flag to desc_hsisoc_cache for
> consistency and correctness on platforms with DMA zone restrictions.
> This also protects against future allocations from this cache that
> might omit GFP_DMA.
> 
> Fixes: 3b5fcc9ac2f4 ("usb: dwc2: host: use kmem cache to allocate descriptors")
> Signed-off-by: karthikeyan <karthiproffesional@gmail.com>
> ---
>  drivers/usb/dwc2/hcd.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
> index 30eb8506617c..556d6ab36930 100644
> --- a/drivers/usb/dwc2/hcd.c
> +++ b/drivers/usb/dwc2/hcd.c
> @@ -5273,7 +5273,7 @@ int dwc2_hcd_init(struct dwc2_hsotg *hsotg)
> 
>                 hsotg->desc_hsisoc_cache = kmem_cache_create("dwc2-hsisoc-desc",
>                                 sizeof(struct dwc2_dma_desc) *
> -                               MAX_DMA_DESC_NUM_HS_ISOC, 512, 0, NULL);
> +                               MAX_DMA_DESC_NUM_HS_ISOC, 512,
> SLAB_CACHE_DMA, NULL);
>                 if (!hsotg->desc_hsisoc_cache) {
>                         dev_err(hsotg->dev,
>                                 "unable to create dwc2 hs isoc desc cache\n");
> --
> 2.34.1
> 


Hi,

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