* [PATCH] dmaengine: Constify struct dma_descriptor_metadata_ops
@ 2026-07-14 14:06 Christophe JAILLET
2026-07-14 14:23 ` Frank Li
2026-07-14 14:29 ` Sai Sree Kartheek Adivi
0 siblings, 2 replies; 3+ messages in thread
From: Christophe JAILLET @ 2026-07-14 14:06 UTC (permalink / raw)
To: Vignesh Raghavendra, Vinod Koul, Frank Li, Michal Simek
Cc: linux-kernel, kernel-janitors, Christophe JAILLET, dmaengine,
linux-arm-kernel
'struct dma_descriptor_metadata_ops' in not modified in these drivers.
Constifying these structures moves some data to a read-only section, so
increases overall security, especially when the structure holds some
function pointers.
On a x86_64, with allmodconfig, as an example:
Before:
======
text data bss dec hex filename
120635 21584 64 142283 22bcb drivers/dma/xilinx/xilinx_dma.o
After:
=====
text data bss dec hex filename
120699 21520 64 142283 22bcb drivers/dma/xilinx/xilinx_dma.o
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
Compile tested only.
---
drivers/dma/ti/k3-udma.c | 2 +-
drivers/dma/xilinx/xilinx_dma.c | 2 +-
include/linux/dmaengine.h | 2 +-
3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
index 1cf158eb7bdb..fb21e0df5ab7 100644
--- a/drivers/dma/ti/k3-udma.c
+++ b/drivers/dma/ti/k3-udma.c
@@ -3408,7 +3408,7 @@ static int udma_set_metadata_len(struct dma_async_tx_descriptor *desc,
return 0;
}
-static struct dma_descriptor_metadata_ops metadata_ops = {
+static const struct dma_descriptor_metadata_ops metadata_ops = {
.attach = udma_attach_metadata,
.get_ptr = udma_get_metadata_ptr,
.set_len = udma_set_metadata_len,
diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c
index 98b41b8f8915..bef2b031dba1 100644
--- a/drivers/dma/xilinx/xilinx_dma.c
+++ b/drivers/dma/xilinx/xilinx_dma.c
@@ -655,7 +655,7 @@ static void *xilinx_dma_get_metadata_ptr(struct dma_async_tx_descriptor *tx,
return seg->hw.app;
}
-static struct dma_descriptor_metadata_ops xilinx_dma_metadata_ops = {
+static const struct dma_descriptor_metadata_ops xilinx_dma_metadata_ops = {
.get_ptr = xilinx_dma_get_metadata_ptr,
};
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 6fe46c0c9452..fe33a20abc61 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -631,7 +631,7 @@ struct dma_async_tx_descriptor {
void *callback_param;
struct dmaengine_unmap_data *unmap;
enum dma_desc_metadata_mode desc_metadata_mode;
- struct dma_descriptor_metadata_ops *metadata_ops;
+ const struct dma_descriptor_metadata_ops *metadata_ops;
#ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
struct dma_async_tx_descriptor *next;
struct dma_async_tx_descriptor *parent;
--
2.55.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] dmaengine: Constify struct dma_descriptor_metadata_ops
2026-07-14 14:06 [PATCH] dmaengine: Constify struct dma_descriptor_metadata_ops Christophe JAILLET
@ 2026-07-14 14:23 ` Frank Li
2026-07-14 14:29 ` Sai Sree Kartheek Adivi
1 sibling, 0 replies; 3+ messages in thread
From: Frank Li @ 2026-07-14 14:23 UTC (permalink / raw)
To: Christophe JAILLET
Cc: Vignesh Raghavendra, Vinod Koul, Frank Li, Michal Simek,
linux-kernel, kernel-janitors, dmaengine, linux-arm-kernel
On Tue, Jul 14, 2026 at 04:06:33PM +0200, Christophe JAILLET wrote:
> 'struct dma_descriptor_metadata_ops' in not modified in these drivers.
>
> Constifying these structures moves some data to a read-only section, so
> increases overall security, especially when the structure holds some
> function pointers.
>
> On a x86_64, with allmodconfig, as an example:
> Before:
> ======
> text data bss dec hex filename
> 120635 21584 64 142283 22bcb drivers/dma/xilinx/xilinx_dma.o
>
> After:
> =====
> text data bss dec hex filename
> 120699 21520 64 142283 22bcb drivers/dma/xilinx/xilinx_dma.o
>
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
> ---
> Compile tested only.
> ---
> drivers/dma/ti/k3-udma.c | 2 +-
> drivers/dma/xilinx/xilinx_dma.c | 2 +-
> include/linux/dmaengine.h | 2 +-
> 3 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
> index 1cf158eb7bdb..fb21e0df5ab7 100644
> --- a/drivers/dma/ti/k3-udma.c
> +++ b/drivers/dma/ti/k3-udma.c
> @@ -3408,7 +3408,7 @@ static int udma_set_metadata_len(struct dma_async_tx_descriptor *desc,
> return 0;
> }
>
> -static struct dma_descriptor_metadata_ops metadata_ops = {
> +static const struct dma_descriptor_metadata_ops metadata_ops = {
> .attach = udma_attach_metadata,
> .get_ptr = udma_get_metadata_ptr,
> .set_len = udma_set_metadata_len,
> diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c
> index 98b41b8f8915..bef2b031dba1 100644
> --- a/drivers/dma/xilinx/xilinx_dma.c
> +++ b/drivers/dma/xilinx/xilinx_dma.c
> @@ -655,7 +655,7 @@ static void *xilinx_dma_get_metadata_ptr(struct dma_async_tx_descriptor *tx,
> return seg->hw.app;
> }
>
> -static struct dma_descriptor_metadata_ops xilinx_dma_metadata_ops = {
> +static const struct dma_descriptor_metadata_ops xilinx_dma_metadata_ops = {
> .get_ptr = xilinx_dma_get_metadata_ptr,
> };
>
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index 6fe46c0c9452..fe33a20abc61 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -631,7 +631,7 @@ struct dma_async_tx_descriptor {
> void *callback_param;
> struct dmaengine_unmap_data *unmap;
> enum dma_desc_metadata_mode desc_metadata_mode;
> - struct dma_descriptor_metadata_ops *metadata_ops;
> + const struct dma_descriptor_metadata_ops *metadata_ops;
> #ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
> struct dma_async_tx_descriptor *next;
> struct dma_async_tx_descriptor *parent;
> --
> 2.55.0
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] dmaengine: Constify struct dma_descriptor_metadata_ops
2026-07-14 14:06 [PATCH] dmaengine: Constify struct dma_descriptor_metadata_ops Christophe JAILLET
2026-07-14 14:23 ` Frank Li
@ 2026-07-14 14:29 ` Sai Sree Kartheek Adivi
1 sibling, 0 replies; 3+ messages in thread
From: Sai Sree Kartheek Adivi @ 2026-07-14 14:29 UTC (permalink / raw)
To: Christophe JAILLET
Cc: Vignesh Raghavendra, Vinod Koul, Frank Li, Michal Simek,
linux-kernel, kernel-janitors, dmaengine, linux-arm-kernel
On Tue, 14 Jul 2026 at 19:45, Christophe JAILLET
<christophe.jaillet@wanadoo.fr> wrote:
>
> 'struct dma_descriptor_metadata_ops' in not modified in these drivers.
>
> Constifying these structures moves some data to a read-only section, so
> increases overall security, especially when the structure holds some
> function pointers.
>
> On a x86_64, with allmodconfig, as an example:
> Before:
> ======
> text data bss dec hex filename
> 120635 21584 64 142283 22bcb drivers/dma/xilinx/xilinx_dma.o
>
> After:
> =====
> text data bss dec hex filename
> 120699 21520 64 142283 22bcb drivers/dma/xilinx/xilinx_dma.o
>
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Sai Sree Kartheek Adivi <s-adivi@ti.com>
> ---
> Compile tested only.
> ---
> drivers/dma/ti/k3-udma.c | 2 +-
> drivers/dma/xilinx/xilinx_dma.c | 2 +-
> include/linux/dmaengine.h | 2 +-
> 3 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
> index 1cf158eb7bdb..fb21e0df5ab7 100644
> --- a/drivers/dma/ti/k3-udma.c
> +++ b/drivers/dma/ti/k3-udma.c
> @@ -3408,7 +3408,7 @@ static int udma_set_metadata_len(struct dma_async_tx_descriptor *desc,
> return 0;
> }
>
> -static struct dma_descriptor_metadata_ops metadata_ops = {
> +static const struct dma_descriptor_metadata_ops metadata_ops = {
> .attach = udma_attach_metadata,
> .get_ptr = udma_get_metadata_ptr,
> .set_len = udma_set_metadata_len,
> diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c
> index 98b41b8f8915..bef2b031dba1 100644
> --- a/drivers/dma/xilinx/xilinx_dma.c
> +++ b/drivers/dma/xilinx/xilinx_dma.c
> @@ -655,7 +655,7 @@ static void *xilinx_dma_get_metadata_ptr(struct dma_async_tx_descriptor *tx,
> return seg->hw.app;
> }
>
> -static struct dma_descriptor_metadata_ops xilinx_dma_metadata_ops = {
> +static const struct dma_descriptor_metadata_ops xilinx_dma_metadata_ops = {
> .get_ptr = xilinx_dma_get_metadata_ptr,
> };
>
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index 6fe46c0c9452..fe33a20abc61 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -631,7 +631,7 @@ struct dma_async_tx_descriptor {
> void *callback_param;
> struct dmaengine_unmap_data *unmap;
> enum dma_desc_metadata_mode desc_metadata_mode;
> - struct dma_descriptor_metadata_ops *metadata_ops;
> + const struct dma_descriptor_metadata_ops *metadata_ops;
> #ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
> struct dma_async_tx_descriptor *next;
> struct dma_async_tx_descriptor *parent;
> --
> 2.55.0
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-07-14 14:06 [PATCH] dmaengine: Constify struct dma_descriptor_metadata_ops Christophe JAILLET
2026-07-14 14:23 ` Frank Li
2026-07-14 14:29 ` Sai Sree Kartheek Adivi
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