* Re: [PATCH 5/6] staging: sm750fb: sw_i2c_write_byte: return -ETIMEDOUT on timeout
From: Dan Carpenter @ 2026-03-04 14:29 UTC (permalink / raw)
To: Soham Kute
Cc: sudipm.mukherjee, teddy.wang, gregkh, linux-fbdev, linux-staging,
linux-kernel
In-Reply-To: <20260304084545.156170-6-officialsohamkute@gmail.com>
On Wed, Mar 04, 2026 at 02:15:44PM +0530, Soham Kute wrote:
> Return -ETIMEDOUT instead of -1 when the I2C byte write times out.
> The callers check for non-zero return value and treat it as failure.
>
"The callers either ignore errors or treat all non-zero returns as
failure and return -1."
> Signed-off-by: Soham Kute <officialsohamkute@gmail.com>
> ---
> drivers/staging/sm750fb/ddk750_swi2c.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/sm750fb/ddk750_swi2c.c b/drivers/staging/sm750fb/ddk750_swi2c.c
> index 0ef8d4ff2ef9..a17f758dda6c 100644
> --- a/drivers/staging/sm750fb/ddk750_swi2c.c
> +++ b/drivers/staging/sm750fb/ddk750_swi2c.c
> @@ -294,7 +294,7 @@ static long sw_i2c_write_byte(unsigned char data)
Need to update the comments at the start of the function as well.
234 /*
235 * This function writes one byte to the slave device
236 *
237 * Parameters:
238 * data - Data to be write to the slave device
239 *
240 * Return Value:
241 * 0 - Success
242 * -1 - Fail to write byte
^^^^^^^^^^^^^^^^^^^^^^^^^
243 */
244 static long sw_i2c_write_byte(unsigned char data)
> if (i < 0xff)
> return 0;
> else
> - return -1;
> + return -ETIMEDOUT;
I don't think -ETIMEDOUT is the correct error code. Maybe -EIO or
-EINVAL.
regards,
dan carpenter
^ permalink raw reply
* Re: [PATCH 6/6] staging: sm750fb: sm750_sw_i2c_init: return -EINVAL for invalid GPIO
From: Dan Carpenter @ 2026-03-04 14:30 UTC (permalink / raw)
To: Soham Kute
Cc: sudipm.mukherjee, teddy.wang, gregkh, linux-fbdev, linux-staging,
linux-kernel
In-Reply-To: <20260304084545.156170-7-officialsohamkute@gmail.com>
On Wed, Mar 04, 2026 at 02:15:45PM +0530, Soham Kute wrote:
> Return -EINVAL instead of -1 when the GPIO pin number is out of
> range. The caller checks for non-zero return value as failure.
>
The caller ignores errors.
> Signed-off-by: Soham Kute <officialsohamkute@gmail.com>
> ---
> drivers/staging/sm750fb/ddk750_swi2c.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/sm750fb/ddk750_swi2c.c b/drivers/staging/sm750fb/ddk750_swi2c.c
> index a17f758dda6c..d90a93ab8fdc 100644
> --- a/drivers/staging/sm750fb/ddk750_swi2c.c
> +++ b/drivers/staging/sm750fb/ddk750_swi2c.c
> @@ -394,7 +394,7 @@ long sm750_sw_i2c_init(unsigned char clk_gpio, unsigned char data_gpio)
> * range is only from [0..63]
> */
> if ((clk_gpio > 31) || (data_gpio > 31))
> - return -1;
> + return -EINVAL;
Need to update the comments for the function.
regards,
dan carpenter
>
> if (sm750_get_chip_type() == SM750LE)
> return sm750le_i2c_init(clk_gpio, data_gpio);
> --
> 2.34.1
^ permalink raw reply
* [PATCH] fbdev: wmt_ge_rops: use devm_platform_ioremap_resource()
From: Amin GATTOUT @ 2026-03-04 17:10 UTC (permalink / raw)
To: Alexey Charkov, Krzysztof Kozlowski, Helge Deller
Cc: linux-arm-kernel, linux-fbdev, dri-devel, linux-kernel,
Thomas Zimmermann, Amin GATTOUT
Replace the open-coded platform_get_resource() + ioremap() pair with
devm_platform_ioremap_resource(), which requests the memory region and
maps it in a single call, with automatic cleanup on device removal.
Also reset regbase to NULL in remove() so that the single-instance
guard in probe() works correctly if the device is re-probed.
Signed-off-by: Amin GATTOUT <amin.gattout@gmail.com>
---
drivers/video/fbdev/wmt_ge_rops.c | 18 ++++--------------
1 file changed, 4 insertions(+), 14 deletions(-)
diff --git a/drivers/video/fbdev/wmt_ge_rops.c b/drivers/video/fbdev/wmt_ge_rops.c
index 2bd26bfb2b46..0cf78bcadfa6 100644
--- a/drivers/video/fbdev/wmt_ge_rops.c
+++ b/drivers/video/fbdev/wmt_ge_rops.c
@@ -148,25 +148,15 @@ EXPORT_SYMBOL_GPL(wmt_ge_sync);
static int wmt_ge_rops_probe(struct platform_device *pdev)
{
- struct resource *res;
-
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (res == NULL) {
- dev_err(&pdev->dev, "no I/O memory resource defined\n");
- return -ENODEV;
- }
-
/* Only one ROP engine is presently supported. */
if (unlikely(regbase)) {
WARN_ON(1);
return -EBUSY;
}
- regbase = ioremap(res->start, resource_size(res));
- if (regbase == NULL) {
- dev_err(&pdev->dev, "failed to map I/O memory\n");
- return -EBUSY;
- }
+ regbase = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(regbase))
+ return PTR_ERR(regbase);
writel(1, regbase + GE_ENABLE_OFF);
printk(KERN_INFO "Enabled support for WMT GE raster acceleration\n");
@@ -176,7 +166,7 @@ static int wmt_ge_rops_probe(struct platform_device *pdev)
static void wmt_ge_rops_remove(struct platform_device *pdev)
{
- iounmap(regbase);
+ regbase = NULL;
}
static const struct of_device_id wmt_dt_ids[] = {
---
base-commit: 11439c4635edd669ae435eec308f4ab8a0804808
change-id: 20260303-master-4dbb344c9a39
Best regards,
--
Amin GATTOUT <amin.gattout@gmail.com>
^ permalink raw reply related
* [PATCH 1/6] staging: sm750fb: hw_sm750le_de_wait: return -ETIMEDOUT on timeout
From: Soham Kute @ 2026-03-04 17:35 UTC (permalink / raw)
To: sudipm.mukherjee, teddy.wang
Cc: gregkh, linux-fbdev, linux-staging, linux-kernel, dan.carpenter,
Soham Kute
In-Reply-To: <aaVT1mSeKrSSlrha@stanley.mountain>
Return -ETIMEDOUT instead of -1 when the DE engine poll loop
times out. The callers check for non-zero return value and
propagate the error code back to their callers.
Signed-off-by: Soham Kute <officialsohamkute@gmail.com>
---
drivers/staging/sm750fb/sm750_hw.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/sm750fb/sm750_hw.c b/drivers/staging/sm750fb/sm750_hw.c
index ce46f240cbaf..e4b6b254335e 100644
--- a/drivers/staging/sm750fb/sm750_hw.c
+++ b/drivers/staging/sm750fb/sm750_hw.c
@@ -518,7 +518,7 @@ int hw_sm750le_de_wait(void)
return 0;
}
/* timeout error */
- return -1;
+ return -ETIMEDOUT;
}
int hw_sm750_de_wait(void)
@@ -536,7 +536,7 @@ int hw_sm750_de_wait(void)
return 0;
}
/* timeout error */
- return -1;
+ return -ETIMEDOUT;
}
int hw_sm750_pan_display(struct lynxfb_crtc *crtc,
--
2.34.1
^ permalink raw reply related
* [PATCH 2/6] staging: sm750fb: sm750_hw_fillrect: propagate de_wait() error
From: Soham Kute @ 2026-03-04 17:35 UTC (permalink / raw)
To: sudipm.mukherjee, teddy.wang
Cc: gregkh, linux-fbdev, linux-staging, linux-kernel, dan.carpenter,
Soham Kute
In-Reply-To: <20260304173529.192067-1-officialsohamkute@gmail.com>
Propagate the error from accel->de_wait() instead of returning -1.
The caller treats all non-zero return values as failure.
Signed-off-by: Soham Kute <officialsohamkute@gmail.com>
---
drivers/staging/sm750fb/sm750_accel.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/drivers/staging/sm750fb/sm750_accel.c b/drivers/staging/sm750fb/sm750_accel.c
index 046b9282b24a..1bd0502db039 100644
--- a/drivers/staging/sm750fb/sm750_accel.c
+++ b/drivers/staging/sm750fb/sm750_accel.c
@@ -90,14 +90,12 @@ int sm750_hw_fillrect(struct lynx_accel *accel,
u32 color, u32 rop)
{
u32 de_ctrl;
+ int ret;
- if (accel->de_wait() != 0) {
- /*
- * int time wait and always busy,seems hardware
- * got something error
- */
+ ret = accel->de_wait();
+ if (ret) {
pr_debug("De engine always busy\n");
- return -1;
+ return ret;
}
write_dpr(accel, DE_WINDOW_DESTINATION_BASE, base); /* dpr40 */
--
2.34.1
^ permalink raw reply related
* [PATCH 3/6] staging: sm750fb: sm750_hw_copyarea: propagate de_wait() error
From: Soham Kute @ 2026-03-04 17:35 UTC (permalink / raw)
To: sudipm.mukherjee, teddy.wang
Cc: gregkh, linux-fbdev, linux-staging, linux-kernel, dan.carpenter,
Soham Kute
In-Reply-To: <20260304173529.192067-1-officialsohamkute@gmail.com>
Propagate the error from accel->de_wait() instead of returning -1.
The caller ignores the return value.
Signed-off-by: Soham Kute <officialsohamkute@gmail.com>
---
drivers/staging/sm750fb/sm750_accel.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/sm750fb/sm750_accel.c b/drivers/staging/sm750fb/sm750_accel.c
index 1bd0502db039..f2fde011e7ca 100644
--- a/drivers/staging/sm750fb/sm750_accel.c
+++ b/drivers/staging/sm750fb/sm750_accel.c
@@ -152,6 +152,7 @@ int sm750_hw_copyarea(struct lynx_accel *accel,
unsigned int rop2)
{
unsigned int nDirection, de_ctrl;
+ int ret;
nDirection = LEFT_TO_RIGHT;
/* Direction of ROP2 operation: 1 = Left to Right, (-1) = Right to Left */
@@ -261,8 +262,9 @@ int sm750_hw_copyarea(struct lynx_accel *accel,
DE_WINDOW_WIDTH_DST_MASK) |
(sPitch / Bpp & DE_WINDOW_WIDTH_SRC_MASK)); /* dpr3c */
- if (accel->de_wait() != 0)
- return -1;
+ ret = accel->de_wait();
+ if (ret)
+ return ret;
write_dpr(accel, DE_SOURCE,
((sx << DE_SOURCE_X_K1_SHIFT) & DE_SOURCE_X_K1_MASK) |
--
2.34.1
^ permalink raw reply related
* [PATCH 4/6] staging: sm750fb: sm750_hw_imageblit: propagate de_wait() error
From: Soham Kute @ 2026-03-04 17:35 UTC (permalink / raw)
To: sudipm.mukherjee, teddy.wang
Cc: gregkh, linux-fbdev, linux-staging, linux-kernel, dan.carpenter,
Soham Kute
In-Reply-To: <20260304173529.192067-1-officialsohamkute@gmail.com>
Propagate the error from accel->de_wait() instead of returning -1.
The caller ignores the return value.
Signed-off-by: Soham Kute <officialsohamkute@gmail.com>
---
drivers/staging/sm750fb/sm750_accel.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/sm750fb/sm750_accel.c b/drivers/staging/sm750fb/sm750_accel.c
index f2fde011e7ca..7d11810864ae 100644
--- a/drivers/staging/sm750fb/sm750_accel.c
+++ b/drivers/staging/sm750fb/sm750_accel.c
@@ -325,15 +325,16 @@ int sm750_hw_imageblit(struct lynx_accel *accel, const char *pSrcbuf,
unsigned int ulBytesRemain;
unsigned int de_ctrl = 0;
unsigned char ajRemain[4];
- int i, j;
+ int i, j, ret;
startBit &= 7; /* Just make sure the start bit is within legal range */
ulBytesPerScan = (width + startBit + 7) / 8;
ul4BytesPerScan = ulBytesPerScan & ~3;
ulBytesRemain = ulBytesPerScan & 3;
- if (accel->de_wait() != 0)
- return -1;
+ ret = accel->de_wait();
+ if (ret)
+ return ret;
/*
* 2D Source Base.
--
2.34.1
^ permalink raw reply related
* [PATCH 5/6] staging: sm750fb: sw_i2c_write_byte: return -EIO on failure
From: Soham Kute @ 2026-03-04 17:35 UTC (permalink / raw)
To: sudipm.mukherjee, teddy.wang
Cc: gregkh, linux-fbdev, linux-staging, linux-kernel, dan.carpenter,
Soham Kute
In-Reply-To: <20260304173529.192067-1-officialsohamkute@gmail.com>
Return -EIO instead of -1 when the I2C byte write fails.
The caller ignores the return value.
Signed-off-by: Soham Kute <officialsohamkute@gmail.com>
---
drivers/staging/sm750fb/ddk750_swi2c.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/sm750fb/ddk750_swi2c.c b/drivers/staging/sm750fb/ddk750_swi2c.c
index 0ef8d4ff2ef9..c73943341f66 100644
--- a/drivers/staging/sm750fb/ddk750_swi2c.c
+++ b/drivers/staging/sm750fb/ddk750_swi2c.c
@@ -239,7 +239,7 @@ static void sw_i2c_stop(void)
*
* Return Value:
* 0 - Success
- * -1 - Fail to write byte
+ * -EIO - Fail to write byte
*/
static long sw_i2c_write_byte(unsigned char data)
{
@@ -294,7 +294,7 @@ static long sw_i2c_write_byte(unsigned char data)
if (i < 0xff)
return 0;
else
- return -1;
+ return -EIO;
}
/*
--
2.34.1
^ permalink raw reply related
* [PATCH 6/6] staging: sm750fb: sm750_sw_i2c_init: return -EINVAL for invalid GPIO
From: Soham Kute @ 2026-03-04 17:35 UTC (permalink / raw)
To: sudipm.mukherjee, teddy.wang
Cc: gregkh, linux-fbdev, linux-staging, linux-kernel, dan.carpenter,
Soham Kute
In-Reply-To: <20260304173529.192067-1-officialsohamkute@gmail.com>
Return -EINVAL instead of -1 when the GPIO pin number is out of
range. The caller ignores the return value.
Signed-off-by: Soham Kute <officialsohamkute@gmail.com>
---
drivers/staging/sm750fb/ddk750_swi2c.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/sm750fb/ddk750_swi2c.c b/drivers/staging/sm750fb/ddk750_swi2c.c
index c73943341f66..46599be8d6b9 100644
--- a/drivers/staging/sm750fb/ddk750_swi2c.c
+++ b/drivers/staging/sm750fb/ddk750_swi2c.c
@@ -344,7 +344,7 @@ static unsigned char sw_i2c_read_byte(unsigned char ack)
* data_gpio - The GPIO pin to be used as i2c SDA
*
* Return Value:
- * -1 - Fail to initialize the i2c
+ * -EINVAL - Fail to initialize the i2c
* 0 - Success
*/
static long sm750le_i2c_init(unsigned char clk_gpio, unsigned char data_gpio)
@@ -382,7 +382,7 @@ static long sm750le_i2c_init(unsigned char clk_gpio, unsigned char data_gpio)
* data_gpio - The GPIO pin to be used as i2c SDA
*
* Return Value:
- * -1 - Fail to initialize the i2c
+ * -EINVAL - Fail to initialize the i2c
* 0 - Success
*/
long sm750_sw_i2c_init(unsigned char clk_gpio, unsigned char data_gpio)
@@ -394,7 +394,7 @@ long sm750_sw_i2c_init(unsigned char clk_gpio, unsigned char data_gpio)
* range is only from [0..63]
*/
if ((clk_gpio > 31) || (data_gpio > 31))
- return -1;
+ return -EINVAL;
if (sm750_get_chip_type() == SM750LE)
return sm750le_i2c_init(clk_gpio, data_gpio);
--
2.34.1
^ permalink raw reply related
* Re: [PATCH v2 09/13] lib/fonts: Compare font data for equality with font_data_is_equal()
From: Nathan Chancellor @ 2026-03-05 0:23 UTC (permalink / raw)
To: Thomas Zimmermann
Cc: gregkh, deller, sam, linux-fbdev, dri-devel, linux-kernel
In-Reply-To: <20260302141255.518657-10-tzimmermann@suse.de>
Hi Thomas,
On Mon, Mar 02, 2026 at 03:08:43PM +0100, Thomas Zimmermann wrote:
...
> diff --git a/lib/fonts/fonts.c b/lib/fonts/fonts.c
> index 8c9a6762061c..c9f6328d5dda 100644
> --- a/lib/fonts/fonts.c
> +++ b/lib/fonts/fonts.c
> @@ -12,18 +12,25 @@
> * for more details.
> */
>
> +#include <linux/font.h>
> #include <linux/module.h>
> -#include <linux/types.h>
> #include <linux/string.h>
> +#include <linux/types.h>
> +
> +#include <asm/sections.h>
> #if defined(__mc68000__)
> #include <asm/setup.h>
> #endif
> -#include <linux/font.h>
>
> /*
> * Helpers for font_data_t
> */
>
> +static bool font_data_is_internal(font_data_t *fd)
> +{
> + return is_kernel_rodata((unsigned long)fd);
> +}
> +
> /**
> * font_data_size - Return size of the font data in bytes
> * @fd: Font data
> @@ -37,6 +44,32 @@ unsigned int font_data_size(font_data_t *fd)
> }
> EXPORT_SYMBOL_GPL(font_data_size);
>
> +/**
> + * font_data_is_equal - Compares font data for equality
> + * @lhs: Left-hand side font data
> + * @rhs: Right-hand-size font data
> + *
> + * Font data is equal if is constain the same sequence of values. The
> + * helper also use the checksum, if both arguments contain it. Font data
> + * coming from different origins, internal or from user space, is never
> + * equal. Allowing this would break reference counting.
> + *
> + * Returns:
> + * True if the given font data is equal, false otherwise.
> + */
> +bool font_data_is_equal(font_data_t *lhs, font_data_t *rhs)
> +{
> + if (font_data_is_internal(lhs) != font_data_is_internal(rhs))
> + return false;
This breaks the build when CONFIG_FONT_SUPPORT is a module.
$ cat allno.config
CONFIG_MODULES=y
CONFIG_DRM=m
CONFIG_DRM_PANIC=y
$ make -skj"$(nproc)" ARCH=x86_64 CROSS_COMPILE=x86_64-linux- KCONFIG_ALLCONFIG=1 allnoconfig all
ERROR: modpost: "__end_rodata" [lib/fonts/font.ko] undefined!
make[4]: *** [scripts/Makefile.modpost:147: Module.symvers] Error 1
...
$ scripts/config -s FONT_SUPPORT
m
Cheers,
Nathan
> + if (font_data_size(lhs) != font_data_size(rhs))
> + return false;
> + if (FNTSUM(lhs) && FNTSUM(rhs) && FNTSUM(lhs) != FNTSUM(rhs))
> + return false;
> +
> + return !memcmp(lhs, rhs, FNTSIZE(lhs));
> +}
> +EXPORT_SYMBOL_GPL(font_data_is_equal);
> +
> /*
> * Font lookup
> */
> --
> 2.53.0
>
^ permalink raw reply
* Re: [PATCH 1/6] staging: sm750fb: hw_sm750le_de_wait: return -ETIMEDOUT on timeout
From: Dan Carpenter @ 2026-03-05 5:33 UTC (permalink / raw)
To: Soham Kute
Cc: sudipm.mukherjee, teddy.wang, gregkh, linux-fbdev, linux-staging,
linux-kernel
In-Reply-To: <20260304173529.192067-1-officialsohamkute@gmail.com>
On Wed, Mar 04, 2026 at 11:05:24PM +0530, Soham Kute wrote:
> Return -ETIMEDOUT instead of -1 when the DE engine poll loop
> times out. The callers check for non-zero return value and
> propagate the error code back to their callers.
>
They don't propagate the error back. The callers do:
drivers/staging/sm750fb/sm750_accel.c
87 int sm750_hw_fillrect(struct lynx_accel *accel,
88 u32 base, u32 pitch, u32 Bpp,
89 u32 x, u32 y, u32 width, u32 height,
90 u32 color, u32 rop)
91 {
92 u32 de_ctrl;
93
94 if (accel->de_wait() != 0) {
95 /*
96 * int time wait and always busy,seems hardware
97 * got something error
98 */
99 pr_debug("De engine always busy\n");
100 return -1;
101 }
They return -1. Propagating the errors means:
ret = accel->de_wait();
if (ret)
return ret;
Also this is a v3 patch, it needs v3 in the subject and a little
description of what changed.
https://staticthinking.wordpress.com/2022/07/27/how-to-send-a-v2-patch/
regards,
dan carpenter
^ permalink raw reply
* Re: [PATCH 2/6] staging: sm750fb: sm750_hw_fillrect: propagate de_wait() error
From: Dan Carpenter @ 2026-03-05 5:34 UTC (permalink / raw)
To: Soham Kute
Cc: sudipm.mukherjee, teddy.wang, gregkh, linux-fbdev, linux-staging,
linux-kernel
In-Reply-To: <20260304173529.192067-2-officialsohamkute@gmail.com>
On Wed, Mar 04, 2026 at 11:05:25PM +0530, Soham Kute wrote:
> Propagate the error from accel->de_wait() instead of returning -1.
> The caller treats all non-zero return values as failure.
No, the caller just ignores the errors.
regards,
dan carpenter
^ permalink raw reply
* Re: [PATCH 6/6] staging: sm750fb: sm750_sw_i2c_init: return -EINVAL for invalid GPIO
From: Dan Carpenter @ 2026-03-05 5:48 UTC (permalink / raw)
To: Soham Kute
Cc: sudipm.mukherjee, teddy.wang, gregkh, linux-fbdev, linux-staging,
linux-kernel
In-Reply-To: <20260304173529.192067-6-officialsohamkute@gmail.com>
On Wed, Mar 04, 2026 at 11:05:29PM +0530, Soham Kute wrote:
> Return -EINVAL instead of -1 when the GPIO pin number is out of
> range. The caller ignores the return value.
>
> Signed-off-by: Soham Kute <officialsohamkute@gmail.com>
> ---
> drivers/staging/sm750fb/ddk750_swi2c.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/staging/sm750fb/ddk750_swi2c.c b/drivers/staging/sm750fb/ddk750_swi2c.c
> index c73943341f66..46599be8d6b9 100644
> --- a/drivers/staging/sm750fb/ddk750_swi2c.c
> +++ b/drivers/staging/sm750fb/ddk750_swi2c.c
> @@ -344,7 +344,7 @@ static unsigned char sw_i2c_read_byte(unsigned char ack)
> * data_gpio - The GPIO pin to be used as i2c SDA
> *
> * Return Value:
> - * -1 - Fail to initialize the i2c
> + * -EINVAL - Fail to initialize the i2c
> * 0 - Success
> */
> static long sm750le_i2c_init(unsigned char clk_gpio, unsigned char data_gpio)
This part needs to be done in the patch that changes
sw_i2c_read_byte().
regards,
dan carpenter
> @@ -382,7 +382,7 @@ static long sm750le_i2c_init(unsigned char clk_gpio, unsigned char data_gpio)
> * data_gpio - The GPIO pin to be used as i2c SDA
> *
> * Return Value:
> - * -1 - Fail to initialize the i2c
> + * -EINVAL - Fail to initialize the i2c
> * 0 - Success
> */
> long sm750_sw_i2c_init(unsigned char clk_gpio, unsigned char data_gpio)
> @@ -394,7 +394,7 @@ long sm750_sw_i2c_init(unsigned char clk_gpio, unsigned char data_gpio)
> * range is only from [0..63]
> */
> if ((clk_gpio > 31) || (data_gpio > 31))
> - return -1;
> + return -EINVAL;
>
> if (sm750_get_chip_type() == SM750LE)
> return sm750le_i2c_init(clk_gpio, data_gpio);
> --
> 2.34.1
>
^ permalink raw reply
* Re: [PATCH] fbdev: wmt_ge_rops: use devm_platform_ioremap_resource()
From: Helge Deller @ 2026-03-05 8:26 UTC (permalink / raw)
To: Amin GATTOUT, Alexey Charkov, Krzysztof Kozlowski
Cc: linux-arm-kernel, linux-fbdev, dri-devel, linux-kernel,
Thomas Zimmermann
In-Reply-To: <20260304-master-v1-1-2bfeb1b9559f@gmail.com>
On 3/4/26 18:10, Amin GATTOUT wrote:
> Replace the open-coded platform_get_resource() + ioremap() pair with
> devm_platform_ioremap_resource(), which requests the memory region and
> maps it in a single call, with automatic cleanup on device removal.
>
> Also reset regbase to NULL in remove() so that the single-instance
> guard in probe() works correctly if the device is re-probed.
>
> Signed-off-by: Amin GATTOUT <amin.gattout@gmail.com>
> ---
> drivers/video/fbdev/wmt_ge_rops.c | 18 ++++--------------
> 1 file changed, 4 insertions(+), 14 deletions(-)
applied to fbdev git tree.
Thanks!
Helge
^ permalink raw reply
* Re: [PATCH v2 09/13] lib/fonts: Compare font data for equality with font_data_is_equal()
From: Thomas Zimmermann @ 2026-03-05 9:31 UTC (permalink / raw)
To: Nathan Chancellor
Cc: gregkh, deller, sam, linux-fbdev, dri-devel, linux-kernel
In-Reply-To: <20260305002347.GA4102761@ax162>
[-- Attachment #1: Type: text/plain, Size: 1348 bytes --]
Hi
Am 05.03.26 um 01:23 schrieb Nathan Chancellor:
[...]
>>
>> +static bool font_data_is_internal(font_data_t *fd)
>> +{
>> + return is_kernel_rodata((unsigned long)fd);
>> +}
>> +
[...]
>>
>> This breaks the build when CONFIG_FONT_SUPPORT is a module.
>>
>> $ cat allno.config
>> CONFIG_MODULES=y
>> CONFIG_DRM=m
>> CONFIG_DRM_PANIC=y
>>
>> $ make -skj"$(nproc)" ARCH=x86_64 CROSS_COMPILE=x86_64-linux- KCONFIG_ALLCONFIG=1 allnoconfig all
>> ERROR: modpost: "__end_rodata" [lib/fonts/font.ko] undefined!
>> make[4]: *** [scripts/Makefile.modpost:147: Module.symvers] Error 1
>> ...
>>
>> $ scripts/config -s FONT_SUPPORT
>> m
Thanks for testing. The attached patch fixes the problem for me. Could
you please test?
Best regards
Thomas
>>
>> Cheers,
>> Nathan
>>
>>
>> + if (font_data_size(lhs) != font_data_size(rhs))
>> + return false;
>> + if (FNTSUM(lhs) && FNTSUM(rhs) && FNTSUM(lhs) != FNTSUM(rhs))
>> + return false;
>> +
>> + return !memcmp(lhs, rhs, FNTSIZE(lhs));
>> +}
>> +EXPORT_SYMBOL_GPL(font_data_is_equal);
>> +
>> /*
>> * Font lookup
>> */
>> --
>> 2.53.0
>>
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)
[-- Attachment #2: 0001-test-for-internal-fonts-by-refcount.patch --]
[-- Type: text/x-patch, Size: 927 bytes --]
From 8dc48d2e676d1437584794f4df3dd20d08878655 Mon Sep 17 00:00:00 2001
From: Thomas Zimmermann <tzimmermann@suse.de>
Date: Thu, 5 Mar 2026 09:28:28 +0100
Subject: [PATCH] test for internal fonts by refcount
Internal font data is 'static const'. Hence test against the refcount
being zero.
---
lib/fonts/fonts.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/lib/fonts/fonts.c b/lib/fonts/fonts.c
index 198aae869be2..b73d74b977ec 100644
--- a/lib/fonts/fonts.c
+++ b/lib/fonts/fonts.c
@@ -45,14 +45,11 @@ static struct font_data *to_font_data_struct(font_data_t *fd)
static bool font_data_is_internal(font_data_t *fd)
{
- return is_kernel_rodata((unsigned long)fd);
+ return !REFCOUNT(fd); /* internal fonts have no reference counting */
}
static void font_data_free(font_data_t *fd)
{
- if (WARN_ON(font_data_is_internal(fd)))
- return;
-
kfree(to_font_data_struct(fd));
}
--
2.53.0
^ permalink raw reply related
* [PATCH] fbdev: macfb: Replace deprecated strcpy with strscpy
From: Thorsten Blum @ 2026-03-05 10:39 UTC (permalink / raw)
To: Helge Deller; +Cc: Thorsten Blum, linux-fbdev, dri-devel, linux-kernel
strcpy() has been deprecated [1] because it performs no bounds checking
on the destination buffer, which can lead to buffer overflows. Replace
it with the safer strscpy(). No functional changes.
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strcpy [1]
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
drivers/video/fbdev/macfb.c | 38 ++++++++++++++++++-------------------
1 file changed, 19 insertions(+), 19 deletions(-)
diff --git a/drivers/video/fbdev/macfb.c b/drivers/video/fbdev/macfb.c
index 887fffdccd24..ef3d2304e2f4 100644
--- a/drivers/video/fbdev/macfb.c
+++ b/drivers/video/fbdev/macfb.c
@@ -668,19 +668,19 @@ static int __init macfb_init(void)
switch(ndev->dr_hw) {
case NUBUS_DRHW_APPLE_MDC:
- strcpy(macfb_fix.id, "Mac Disp. Card");
+ strscpy(macfb_fix.id, "Mac Disp. Card");
macfb_setpalette = mdc_setpalette;
break;
case NUBUS_DRHW_APPLE_TFB:
- strcpy(macfb_fix.id, "Toby");
+ strscpy(macfb_fix.id, "Toby");
macfb_setpalette = toby_setpalette;
break;
case NUBUS_DRHW_APPLE_JET:
- strcpy(macfb_fix.id, "Jet");
+ strscpy(macfb_fix.id, "Jet");
macfb_setpalette = jet_setpalette;
break;
default:
- strcpy(macfb_fix.id, "Generic NuBus");
+ strscpy(macfb_fix.id, "Generic NuBus");
break;
}
}
@@ -707,7 +707,7 @@ static int __init macfb_init(void)
case MAC_MODEL_Q700:
case MAC_MODEL_Q900:
case MAC_MODEL_Q950:
- strcpy(macfb_fix.id, "DAFB");
+ strscpy(macfb_fix.id, "DAFB");
macfb_setpalette = dafb_setpalette;
dafb_cmap_regs = ioremap(DAFB_BASE, 0x1000);
break;
@@ -716,7 +716,7 @@ static int __init macfb_init(void)
* LC II uses the V8 framebuffer
*/
case MAC_MODEL_LCII:
- strcpy(macfb_fix.id, "V8");
+ strscpy(macfb_fix.id, "V8");
macfb_setpalette = v8_brazil_setpalette;
v8_brazil_cmap_regs = ioremap(DAC_BASE, 0x1000);
break;
@@ -729,7 +729,7 @@ static int __init macfb_init(void)
case MAC_MODEL_IIVI:
case MAC_MODEL_IIVX:
case MAC_MODEL_P600:
- strcpy(macfb_fix.id, "Brazil");
+ strscpy(macfb_fix.id, "Brazil");
macfb_setpalette = v8_brazil_setpalette;
v8_brazil_cmap_regs = ioremap(DAC_BASE, 0x1000);
break;
@@ -745,7 +745,7 @@ static int __init macfb_init(void)
case MAC_MODEL_P520:
case MAC_MODEL_P550:
case MAC_MODEL_P460:
- strcpy(macfb_fix.id, "Sonora");
+ strscpy(macfb_fix.id, "Sonora");
macfb_setpalette = v8_brazil_setpalette;
v8_brazil_cmap_regs = ioremap(DAC_BASE, 0x1000);
break;
@@ -757,7 +757,7 @@ static int __init macfb_init(void)
*/
case MAC_MODEL_IICI:
case MAC_MODEL_IISI:
- strcpy(macfb_fix.id, "RBV");
+ strscpy(macfb_fix.id, "RBV");
macfb_setpalette = rbv_setpalette;
rbv_cmap_regs = ioremap(DAC_BASE, 0x1000);
break;
@@ -767,7 +767,7 @@ static int __init macfb_init(void)
*/
case MAC_MODEL_Q840:
case MAC_MODEL_C660:
- strcpy(macfb_fix.id, "Civic");
+ strscpy(macfb_fix.id, "Civic");
macfb_setpalette = civic_setpalette;
civic_cmap_regs = ioremap(CIVIC_BASE, 0x1000);
break;
@@ -778,7 +778,7 @@ static int __init macfb_init(void)
* We think this may be like the LC II
*/
case MAC_MODEL_LC:
- strcpy(macfb_fix.id, "LC");
+ strscpy(macfb_fix.id, "LC");
if (vidtest) {
macfb_setpalette = v8_brazil_setpalette;
v8_brazil_cmap_regs =
@@ -790,7 +790,7 @@ static int __init macfb_init(void)
* We think this may be like the LC II
*/
case MAC_MODEL_CCL:
- strcpy(macfb_fix.id, "Color Classic");
+ strscpy(macfb_fix.id, "Color Classic");
if (vidtest) {
macfb_setpalette = v8_brazil_setpalette;
v8_brazil_cmap_regs =
@@ -802,7 +802,7 @@ static int __init macfb_init(void)
* And we *do* mean "weirdos"
*/
case MAC_MODEL_TV:
- strcpy(macfb_fix.id, "Mac TV");
+ strscpy(macfb_fix.id, "Mac TV");
break;
/*
@@ -810,7 +810,7 @@ static int __init macfb_init(void)
*/
case MAC_MODEL_SE30:
case MAC_MODEL_CLII:
- strcpy(macfb_fix.id, "Monochrome");
+ strscpy(macfb_fix.id, "Monochrome");
break;
/*
@@ -828,7 +828,7 @@ static int __init macfb_init(void)
case MAC_MODEL_PB140:
case MAC_MODEL_PB145:
case MAC_MODEL_PB170:
- strcpy(macfb_fix.id, "DDC");
+ strscpy(macfb_fix.id, "DDC");
break;
/*
@@ -840,7 +840,7 @@ static int __init macfb_init(void)
case MAC_MODEL_PB180:
case MAC_MODEL_PB210:
case MAC_MODEL_PB230:
- strcpy(macfb_fix.id, "GSC");
+ strscpy(macfb_fix.id, "GSC");
break;
/*
@@ -848,7 +848,7 @@ static int __init macfb_init(void)
*/
case MAC_MODEL_PB165C:
case MAC_MODEL_PB180C:
- strcpy(macfb_fix.id, "TIM");
+ strscpy(macfb_fix.id, "TIM");
break;
/*
@@ -860,13 +860,13 @@ static int __init macfb_init(void)
case MAC_MODEL_PB270C:
case MAC_MODEL_PB280:
case MAC_MODEL_PB280C:
- strcpy(macfb_fix.id, "CSC");
+ strscpy(macfb_fix.id, "CSC");
macfb_setpalette = csc_setpalette;
csc_cmap_regs = ioremap(CSC_BASE, 0x1000);
break;
default:
- strcpy(macfb_fix.id, "Unknown");
+ strscpy(macfb_fix.id, "Unknown");
break;
}
--
Thorsten Blum <thorsten.blum@linux.dev>
GPG: 1D60 735E 8AEF 3BE4 73B6 9D84 7336 78FD 8DFE EAD4
^ permalink raw reply related
* Re: [PATCH v2 09/13] lib/fonts: Compare font data for equality with font_data_is_equal()
From: Nathan Chancellor @ 2026-03-05 20:12 UTC (permalink / raw)
To: Thomas Zimmermann
Cc: gregkh, deller, sam, linux-fbdev, dri-devel, linux-kernel
In-Reply-To: <4acb921b-6bce-4bbf-a607-cc3e991dfc3a@suse.de>
On Thu, Mar 05, 2026 at 10:31:13AM +0100, Thomas Zimmermann wrote:
> Thanks for testing. The attached patch fixes the problem for me. Could you
> please test?
Yeah, that appears to work for me as well.
Tested-by: Nathan Chancellor <nathan@kernel.org> # build
It seems like the asm/sections.h include can be dropped as well, since
that was only included for is_kernel_rodata() AFAICT.
> From 8dc48d2e676d1437584794f4df3dd20d08878655 Mon Sep 17 00:00:00 2001
> From: Thomas Zimmermann <tzimmermann@suse.de>
> Date: Thu, 5 Mar 2026 09:28:28 +0100
> Subject: [PATCH] test for internal fonts by refcount
>
> Internal font data is 'static const'. Hence test against the refcount
> being zero.
> ---
> lib/fonts/fonts.c | 5 +----
> 1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/lib/fonts/fonts.c b/lib/fonts/fonts.c
> index 198aae869be2..b73d74b977ec 100644
> --- a/lib/fonts/fonts.c
> +++ b/lib/fonts/fonts.c
> @@ -45,14 +45,11 @@ static struct font_data *to_font_data_struct(font_data_t *fd)
>
> static bool font_data_is_internal(font_data_t *fd)
> {
> - return is_kernel_rodata((unsigned long)fd);
> + return !REFCOUNT(fd); /* internal fonts have no reference counting */
> }
>
> static void font_data_free(font_data_t *fd)
> {
> - if (WARN_ON(font_data_is_internal(fd)))
> - return;
> -
> kfree(to_font_data_struct(fd));
> }
>
> --
> 2.53.0
>
^ permalink raw reply
* Re: [PATCH] fbdev: macfb: Replace deprecated strcpy with strscpy
From: Helge Deller @ 2026-03-06 9:20 UTC (permalink / raw)
To: Thorsten Blum; +Cc: linux-fbdev, dri-devel, linux-kernel
In-Reply-To: <20260305103919.158067-2-thorsten.blum@linux.dev>
On 3/5/26 11:39, Thorsten Blum wrote:
> strcpy() has been deprecated [1] because it performs no bounds checking
> on the destination buffer, which can lead to buffer overflows. Replace
> it with the safer strscpy(). No functional changes.
>
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strcpy [1]
> Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
> ---
> drivers/video/fbdev/macfb.c | 38 ++++++++++++++++++-------------------
> 1 file changed, 19 insertions(+), 19 deletions(-)
applied.
Thanks!
Helge
^ permalink raw reply
* Re: [PATCH v2] backlight: sky81452-backlight: Check return value of devm_gpiod_get_optional() in sky81452_bl_parse_dt()
From: Linus Walleij @ 2026-03-06 13:31 UTC (permalink / raw)
To: Chen Ni
Cc: daniel, danielt, deller, dri-devel, jingoohan1, lee, linux-fbdev,
linux-kernel
In-Reply-To: <20260203021625.578678-1-nichen@iscas.ac.cn>
On Tue, Feb 3, 2026 at 3:17 AM Chen Ni <nichen@iscas.ac.cn> wrote:
> The devm_gpiod_get_optional() function may return an ERR_PTR in case of
> genuine GPIO acquisition errors, not just NULL which indicates the
> legitimate absence of an optional GPIO.
>
> Add an IS_ERR() check after the call in sky81452_bl_parse_dt(). On
> error, return the error code to ensure proper failure handling rather
> than proceeding with invalid pointers.
>
> Fixes: e1915eec54a6 ("backlight: sky81452: Convert to GPIO descriptors")
> Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Yours,
Linus Walleij
^ permalink raw reply
* Re: (subset) [PATCH v2] backlight: sky81452-backlight: Check return value of devm_gpiod_get_optional() in sky81452_bl_parse_dt()
From: Lee Jones @ 2026-03-06 14:21 UTC (permalink / raw)
To: daniel, Chen Ni
Cc: danielt, deller, dri-devel, jingoohan1, lee, linusw, linux-fbdev,
linux-kernel
In-Reply-To: <20260203021625.578678-1-nichen@iscas.ac.cn>
On Tue, 03 Feb 2026 10:16:25 +0800, Chen Ni wrote:
> The devm_gpiod_get_optional() function may return an ERR_PTR in case of
> genuine GPIO acquisition errors, not just NULL which indicates the
> legitimate absence of an optional GPIO.
>
> Add an IS_ERR() check after the call in sky81452_bl_parse_dt(). On
> error, return the error code to ensure proper failure handling rather
> than proceeding with invalid pointers.
>
> [...]
Applied, thanks!
[1/1] backlight: sky81452-backlight: Check return value of devm_gpiod_get_optional() in sky81452_bl_parse_dt()
commit: 797cc011ae02bda26f93d25a4442d7a1a77d84df
--
Lee Jones [李琼斯]
^ permalink raw reply
* [PATCH v12 0/1] rust: interop: Add list module for C linked list interface
From: Joel Fernandes @ 2026-03-06 20:36 UTC (permalink / raw)
To: linux-kernel
Cc: Miguel Ojeda, Boqun Feng, Gary Guo, Björn Roy Baron,
Benno Lossin, Andreas Hindborg, Alice Ryhl, Trevor Gross,
Alex Gaynor, Danilo Krummrich, Dave Airlie, David Airlie,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
Simona Vetter, Daniel Almeida, Koen Koning, Nikola Djukic,
Alexandre Courbot, Philipp Stanner, Elle Rhumsaa, Jonathan Corbet,
Alex Deucher, Christian König, Jani Nikula, Joonas Lahtinen,
Rodrigo Vivi, Tvrtko Ursulin, Huang Rui, Matthew Auld,
Matthew Brost, Lucas De Marchi, Thomas Hellström,
Helge Deller, John Hubbard, Alistair Popple, Timur Tabi,
Edwin Peer, Andrea Righi, Andy Ritger, Zhi Wang, Balbir Singh,
alexeyi, Eliot Courtney, dri-devel, nouveau, rust-for-linux,
linux-doc, amd-gfx, intel-gfx, intel-xe, linux-fbdev,
Joel Fernandes
The interop/list module provides Rust abstractions for iterating over C
list_head-based linked lists. The primary use-case right now is iterating
over GPU buddy allocator blocks.
This series provides the interop/list module required for GPU buddy bindings,
which is inturn required for nova-core memory memory management. This patch is
being sent separately from the rest of the preparatory patches (DRM buddy
movement, GPU buddy bindings, etc.) as it can go in independently.
The git tree with the patch can be found at:
git://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git (tag: interop-v12-20260306)
Change log:
Changes from v11 to v12:
- Renamed module from ffi/clist to interop/list, reflecting community feedback
that 'interop' better describes the purpose than 'ffi' (credit to Boqun for
starting this idea.)
- Updated MAINTAINERS entry from "RUST [FFI HELPER]" to "RUST [INTEROP]"
and updated git tree reference.
- Added Acked-by from Miguel.
Changes from v10 to v11:
- Sending only the ffi/clist patches separately from the rest of the
preparatory series, as these can go in independently.
- MAINTAINERS entry: Renamed from "RUST TO C LIST INTERFACES" to
"RUST [FFI HELPER]" with (CLIST) scope annotations for maintainers,
following Danilo's suggestion. Note: There is still an ongoing
discussion about the MAINTAINER file entry naming between Miguel and
Danilo: https://lore.kernel.org/all/DGJXYEXCYIII.Z6FOAA8YYMAZ@kernel.org/
- Updated clist.rs module documentation per Danilo's review: generalized
the FFI usage description and added explicit note directing Rust-only
users to kernel::list::List instead.
- Implemented suggestions from Alice related to safety of CList wrt
concurrent modifications.
- Removed unnecessary trailing comment markers from example imports.
- Added feature guard for offset_of_nested (Eliot).
Changes from v9 to v10:
- Combined clist/ffi patches into the larger "Preparatory patches for
nova-core memory management" series (8 patches total).
- Added new ffi module patch: Convert pub use to pub mod and create
rust/kernel/ffi/mod.rs to host clist as a sub-module.
- Moved clist from rust/kernel/clist.rs to rust/kernel/ffi/clist.rs.
- Added Reviewed-by and Acked-by tags from Gary and Daniel.
Changes from v8 to v9:
- Added nova-core Kconfig change to select GPU_BUDDY.
- Minor fixups.
Changes from v7 to v8:
- Various changes suggested by Danilo, Gary, Daniel. Added tags.
Changes from v6 to v7:
- Extracted clist and GPU buddy patches from the larger RFC v6 nova-core
memory management series into a standalone series.
- Changes based on suggestions by Gary and Dave.
Changes from v5 to v6:
- Part of the larger RFC v6 nova-core memory management series
(26 patches).
Changes from v4 to v5:
- Part of the larger RFC v5 nova-core memory management series
(6 patches).
Changes from v3 to v4:
- Combined the clist and DRM buddy series back together.
- Added Rust bindings for the GPU buddy allocator.
- Moved DRM buddy allocator one level up to drivers/gpu/ so it can be
used by GPU drivers (e.g. nova-core) that have non-DRM usecases.
Changes from v2 to v3:
- Consolidated 3 patches into a single patch.
Changes from v1 to v2:
- Dropped the DRM buddy allocator patches. Series now focuses solely on
the clist module.
- Dropped samples and added doctests.
- Added proper lifetime management similar to scatterlist.
Link to v11: https://lore.kernel.org/all/20260224222734.3153931-1-joelagnelf@nvidia.com/
Link to v10: https://lore.kernel.org/all/20260218205507.689429-1-joelagnelf@nvidia.com/
Link to v9: https://lore.kernel.org/all/20260210233204.790524-1-joelagnelf@nvidia.com/
Link to v8: https://lore.kernel.org/all/20260209214246.2783990-1-joelagnelf@nvidia.com/
Link to v7: https://lore.kernel.org/all/20260206004110.1914814-1-joelagnelf@nvidia.com/
Joel Fernandes (1):
rust: interop: Add list module for C linked list interface
MAINTAINERS | 8 +
rust/helpers/helpers.c | 1 +
rust/helpers/list.c | 17 ++
rust/kernel/interop/list.rs | 338 ++++++++++++++++++++++++++++++++++++
rust/kernel/interop/mod.rs | 9 +
rust/kernel/lib.rs | 2 +
6 files changed, 375 insertions(+)
create mode 100644 rust/helpers/list.c
create mode 100644 rust/kernel/interop/list.rs
create mode 100644 rust/kernel/interop/mod.rs
base-commit: 877552aa875839314afad7154b5a561889e87ea9
--
2.34.1
^ permalink raw reply
* [PATCH v12 1/1] rust: interop: Add list module for C linked list interface
From: Joel Fernandes @ 2026-03-06 20:36 UTC (permalink / raw)
To: linux-kernel
Cc: Miguel Ojeda, Boqun Feng, Gary Guo, Björn Roy Baron,
Benno Lossin, Andreas Hindborg, Alice Ryhl, Trevor Gross,
Alex Gaynor, Danilo Krummrich, Dave Airlie, David Airlie,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
Simona Vetter, Daniel Almeida, Koen Koning, Nikola Djukic,
Alexandre Courbot, Philipp Stanner, Elle Rhumsaa, Jonathan Corbet,
Alex Deucher, Christian König, Jani Nikula, Joonas Lahtinen,
Rodrigo Vivi, Tvrtko Ursulin, Huang Rui, Matthew Auld,
Matthew Brost, Lucas De Marchi, Thomas Hellström,
Helge Deller, John Hubbard, Alistair Popple, Timur Tabi,
Edwin Peer, Andrea Righi, Andy Ritger, Zhi Wang, Balbir Singh,
alexeyi, Eliot Courtney, dri-devel, nouveau, rust-for-linux,
linux-doc, amd-gfx, intel-gfx, intel-xe, linux-fbdev,
Joel Fernandes, Miguel Ojeda
In-Reply-To: <20260306203648.1136554-1-joelagnelf@nvidia.com>
Add a new module `kernel::interop::list` for working with C's doubly
circular linked lists. Provide low-level iteration over list nodes.
Typed iteration over actual items is provided with a `clist_create`
macro to assist in creation of the `CList` type.
Cc: Nikola Djukic <ndjukic@nvidia.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Gary Guo <gary@garyguo.net>
Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
---
MAINTAINERS | 8 +
rust/helpers/helpers.c | 1 +
rust/helpers/list.c | 17 ++
rust/kernel/interop/list.rs | 338 ++++++++++++++++++++++++++++++++++++
rust/kernel/interop/mod.rs | 9 +
rust/kernel/lib.rs | 2 +
6 files changed, 375 insertions(+)
create mode 100644 rust/helpers/list.c
create mode 100644 rust/kernel/interop/list.rs
create mode 100644 rust/kernel/interop/mod.rs
diff --git a/MAINTAINERS b/MAINTAINERS
index 2842d7529a65..4c66f8261ff2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -23219,6 +23219,14 @@ T: git https://github.com/Rust-for-Linux/linux.git alloc-next
F: rust/kernel/alloc.rs
F: rust/kernel/alloc/
+RUST [INTEROP]
+M: Joel Fernandes <joelagnelf@nvidia.com>
+M: Alexandre Courbot <acourbot@nvidia.com>
+L: rust-for-linux@vger.kernel.org
+S: Maintained
+T: git https://github.com/Rust-for-Linux/linux.git interop-next
+F: rust/kernel/interop/
+
RUST [NUM]
M: Alexandre Courbot <acourbot@nvidia.com>
R: Yury Norov <yury.norov@gmail.com>
diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
index a3c42e51f00a..724fcb8240ac 100644
--- a/rust/helpers/helpers.c
+++ b/rust/helpers/helpers.c
@@ -35,6 +35,7 @@
#include "io.c"
#include "jump_label.c"
#include "kunit.c"
+#include "list.c"
#include "maple_tree.c"
#include "mm.c"
#include "mutex.c"
diff --git a/rust/helpers/list.c b/rust/helpers/list.c
new file mode 100644
index 000000000000..18095a5593c5
--- /dev/null
+++ b/rust/helpers/list.c
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Helpers for C circular doubly linked list implementation.
+ */
+
+#include <linux/list.h>
+
+__rust_helper void rust_helper_INIT_LIST_HEAD(struct list_head *list)
+{
+ INIT_LIST_HEAD(list);
+}
+
+__rust_helper void rust_helper_list_add_tail(struct list_head *new, struct list_head *head)
+{
+ list_add_tail(new, head);
+}
diff --git a/rust/kernel/interop/list.rs b/rust/kernel/interop/list.rs
new file mode 100644
index 000000000000..bd6409f8bca2
--- /dev/null
+++ b/rust/kernel/interop/list.rs
@@ -0,0 +1,338 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust interface for C doubly circular intrusive linked lists.
+//!
+//! This module provides Rust abstractions for iterating over C `list_head`-based
+//! linked lists. It should only be used for cases where C and Rust code share
+//! direct access to the same linked list through a C interop interface.
+//!
+//! Note: This *must not* be used by Rust components that just need a linked list
+//! primitive. Use [`kernel::list::List`] instead.
+//!
+//! # Examples
+//!
+//! ```
+//! use kernel::{
+//! bindings,
+//! clist_create,
+//! types::Opaque,
+//! };
+//! # // Create test list with values (0, 10, 20) - normally done by C code but it is
+//! # // emulated here for doctests using the C bindings.
+//! # use core::mem::MaybeUninit;
+//! #
+//! # /// C struct with embedded `list_head` (typically will be allocated by C code).
+//! # #[repr(C)]
+//! # pub struct SampleItemC {
+//! # pub value: i32,
+//! # pub link: bindings::list_head,
+//! # }
+//! #
+//! # let mut head = MaybeUninit::<bindings::list_head>::uninit();
+//! #
+//! # let head = head.as_mut_ptr();
+//! # // SAFETY: head and all the items are test objects allocated in this scope.
+//! # unsafe { bindings::INIT_LIST_HEAD(head) };
+//! #
+//! # let mut items = [
+//! # MaybeUninit::<SampleItemC>::uninit(),
+//! # MaybeUninit::<SampleItemC>::uninit(),
+//! # MaybeUninit::<SampleItemC>::uninit(),
+//! # ];
+//! #
+//! # for (i, item) in items.iter_mut().enumerate() {
+//! # let ptr = item.as_mut_ptr();
+//! # // SAFETY: `ptr` points to a valid `MaybeUninit<SampleItemC>`.
+//! # unsafe { (*ptr).value = i as i32 * 10 };
+//! # // SAFETY: `&raw mut` creates a pointer valid for `INIT_LIST_HEAD`.
+//! # unsafe { bindings::INIT_LIST_HEAD(&raw mut (*ptr).link) };
+//! # // SAFETY: `link` was just initialized and `head` is a valid list head.
+//! # unsafe { bindings::list_add_tail(&mut (*ptr).link, head) };
+//! # }
+//!
+//! // Rust wrapper for the C struct.
+//! // The list item struct in this example is defined in C code as:
+//! // struct SampleItemC {
+//! // int value;
+//! // struct list_head link;
+//! // };
+//! //
+//! #[repr(transparent)]
+//! pub struct Item(Opaque<SampleItemC>);
+//!
+//! impl Item {
+//! pub fn value(&self) -> i32 {
+//! // SAFETY: [`Item`] has same layout as [`SampleItemC`].
+//! unsafe { (*self.0.get()).value }
+//! }
+//! }
+//!
+//! // Create typed [`CList`] from sentinel head.
+//! // SAFETY: head is valid and initialized, items are `SampleItemC` with
+//! // embedded `link` field, and `Item` is `#[repr(transparent)]` over `SampleItemC`.
+//! let list = clist_create!(unsafe { head, Item, SampleItemC, link });
+//!
+//! // Iterate directly over typed items.
+//! let mut found_0 = false;
+//! let mut found_10 = false;
+//! let mut found_20 = false;
+//!
+//! for item in list.iter() {
+//! let val = item.value();
+//! if val == 0 { found_0 = true; }
+//! if val == 10 { found_10 = true; }
+//! if val == 20 { found_20 = true; }
+//! }
+//!
+//! assert!(found_0 && found_10 && found_20);
+//! ```
+
+use core::{
+ iter::FusedIterator,
+ marker::PhantomData, //
+};
+
+use crate::{
+ bindings,
+ types::Opaque, //
+};
+
+use pin_init::{
+ pin_data,
+ pin_init,
+ PinInit, //
+};
+
+/// FFI wrapper for a C `list_head` object used in intrusive linked lists.
+///
+/// # Invariants
+///
+/// - The underlying `list_head` has been initialized (e.g. via `INIT_LIST_HEAD()`) and its
+/// `next`/`prev` pointers are valid and non-NULL.
+#[pin_data]
+#[repr(transparent)]
+pub struct CListHead {
+ #[pin]
+ inner: Opaque<bindings::list_head>,
+}
+
+impl CListHead {
+ /// Create a `&CListHead` reference from a raw `list_head` pointer.
+ ///
+ /// # Safety
+ ///
+ /// - `ptr` must be a valid pointer to an initialized `list_head` (e.g. via
+ /// `INIT_LIST_HEAD()`), with valid non-NULL `next`/`prev` pointers.
+ /// - `ptr` must remain valid for the lifetime `'a`.
+ /// - The list and all linked `list_head` nodes must not be modified from
+ /// anywhere for the lifetime `'a`, unless done so via any [`CListHead`] APIs.
+ #[inline]
+ pub unsafe fn from_raw<'a>(ptr: *mut bindings::list_head) -> &'a Self {
+ // SAFETY:
+ // - [`CListHead`] has same layout as `list_head`.
+ // - `ptr` is valid and unmodified for 'a per caller guarantees.
+ unsafe { &*ptr.cast() }
+ }
+
+ /// Get the raw `list_head` pointer.
+ #[inline]
+ pub fn as_raw(&self) -> *mut bindings::list_head {
+ self.inner.get()
+ }
+
+ /// Get the next [`CListHead`] in the list.
+ #[inline]
+ pub fn next(&self) -> &Self {
+ let raw = self.as_raw();
+ // SAFETY:
+ // - `self.as_raw()` is valid and initialized per type invariants.
+ // - The `next` pointer is valid and non-NULL per type invariants
+ // (initialized via `INIT_LIST_HEAD()` or equivalent).
+ unsafe { Self::from_raw((*raw).next) }
+ }
+
+ /// Check if this node is linked in a list (not isolated).
+ #[inline]
+ pub fn is_linked(&self) -> bool {
+ let raw = self.as_raw();
+ // SAFETY: self.as_raw() is valid per type invariants.
+ unsafe { (*raw).next != raw && (*raw).prev != raw }
+ }
+
+ /// Pin-initializer that initializes the list head.
+ pub fn new() -> impl PinInit<Self> {
+ pin_init!(Self {
+ // SAFETY: `INIT_LIST_HEAD` initializes `slot` to a valid empty list.
+ inner <- Opaque::ffi_init(|slot| unsafe { bindings::INIT_LIST_HEAD(slot) }),
+ })
+ }
+}
+
+// SAFETY: `list_head` contains no thread-bound state; it only holds
+// `next`/`prev` pointers.
+unsafe impl Send for CListHead {}
+
+// SAFETY: `CListHead` can be shared among threads as modifications are
+// not allowed at the moment.
+unsafe impl Sync for CListHead {}
+
+impl PartialEq for CListHead {
+ #[inline]
+ fn eq(&self, other: &Self) -> bool {
+ core::ptr::eq(self, other)
+ }
+}
+
+impl Eq for CListHead {}
+
+/// Low-level iterator over `list_head` nodes.
+///
+/// An iterator used to iterate over a C intrusive linked list (`list_head`). Caller has to
+/// perform conversion of returned [`CListHead`] to an item (using `container_of` macro or similar).
+///
+/// # Invariants
+///
+/// [`CListHeadIter`] is iterating over an initialized and valid list.
+struct CListHeadIter<'a> {
+ /// Current position in the list.
+ current: &'a CListHead,
+ /// The sentinel head (used to detect end of iteration).
+ sentinel: &'a CListHead,
+}
+
+impl<'a> Iterator for CListHeadIter<'a> {
+ type Item = &'a CListHead;
+
+ #[inline]
+ fn next(&mut self) -> Option<Self::Item> {
+ // Check if we've reached the sentinel (end of list).
+ if self.current == self.sentinel {
+ return None;
+ }
+
+ let item = self.current;
+ self.current = item.next();
+ Some(item)
+ }
+}
+
+impl<'a> FusedIterator for CListHeadIter<'a> {}
+
+/// A typed C linked list with a sentinel head intended for FFI use-cases where
+/// C subsystem manages a linked list that Rust code needs to read. Generally
+/// required only for special cases.
+///
+/// A sentinel head [`CListHead`] represents the entire linked list and can be used
+/// for iteration over items of type `T`, it is not associated with a specific item.
+///
+/// The const generic `OFFSET` specifies the byte offset of the `list_head` field within
+/// the struct that `T` wraps.
+///
+/// # Invariants
+///
+/// - The sentinel [`CListHead`] has been initialized (e.g. via `INIT_LIST_HEAD()`) with valid
+/// non-NULL `next`/`prev` pointers.
+/// - `OFFSET` is the byte offset of the `list_head` field within the struct that `T` wraps.
+/// - All the list's `list_head` nodes have been initialized with valid non-NULL `next`/`prev`
+/// pointers.
+#[repr(transparent)]
+pub struct CList<T, const OFFSET: usize>(CListHead, PhantomData<T>);
+
+impl<T, const OFFSET: usize> CList<T, OFFSET> {
+ /// Create a typed [`CList`] reference from a raw sentinel `list_head` pointer.
+ ///
+ /// # Safety
+ ///
+ /// - `ptr` must be a valid pointer to an initialized sentinel `list_head` (e.g. via
+ /// `INIT_LIST_HEAD()`), with valid non-NULL `next`/`prev` pointers.
+ /// - `ptr` must remain valid for the lifetime `'a`.
+ /// - The list and all linked nodes must not be concurrently modified for the lifetime `'a`.
+ /// - The list must contain items where the `list_head` field is at byte offset `OFFSET`.
+ /// - `T` must be `#[repr(transparent)]` over the C struct.
+ #[inline]
+ pub unsafe fn from_raw<'a>(ptr: *mut bindings::list_head) -> &'a Self {
+ // SAFETY:
+ // - [`CList`] has same layout as [`CListHead`] due to repr(transparent).
+ // - Caller guarantees `ptr` is a valid, sentinel `list_head` object.
+ unsafe { &*ptr.cast() }
+ }
+
+ /// Check if the list is empty.
+ #[inline]
+ pub fn is_empty(&self) -> bool {
+ !self.0.is_linked()
+ }
+
+ /// Create an iterator over typed items.
+ #[inline]
+ pub fn iter(&self) -> CListIter<'_, T, OFFSET> {
+ let head = &self.0;
+ CListIter {
+ head_iter: CListHeadIter {
+ current: head.next(),
+ sentinel: head,
+ },
+ _phantom: PhantomData,
+ }
+ }
+}
+
+/// High-level iterator over typed list items.
+pub struct CListIter<'a, T, const OFFSET: usize> {
+ head_iter: CListHeadIter<'a>,
+ _phantom: PhantomData<&'a T>,
+}
+
+impl<'a, T, const OFFSET: usize> Iterator for CListIter<'a, T, OFFSET> {
+ type Item = &'a T;
+
+ #[inline]
+ fn next(&mut self) -> Option<Self::Item> {
+ let head = self.head_iter.next()?;
+
+ // Convert to item using OFFSET.
+ // SAFETY: The pointer calculation is valid because `OFFSET` is derived
+ // from `offset_of!` per type invariants.
+ Some(unsafe { &*head.as_raw().byte_sub(OFFSET).cast::<T>() })
+ }
+}
+
+impl<'a, T, const OFFSET: usize> FusedIterator for CListIter<'a, T, OFFSET> {}
+
+/// Create a C doubly-circular linked list interface `CList` from a raw `list_head` pointer.
+///
+/// This macro creates a `CList<T, OFFSET>` that can iterate over items of type `$rust_type`
+/// linked via the `$field` field in the underlying C struct `$c_type`.
+///
+/// # Arguments
+///
+/// - `$head`: Raw pointer to the sentinel `list_head` object (`*mut bindings::list_head`).
+/// - `$rust_type`: Each item's rust wrapper type.
+/// - `$c_type`: Each item's C struct type that contains the embedded `list_head`.
+/// - `$field`: The name of the `list_head` field within the C struct.
+///
+/// # Safety
+///
+/// The caller must ensure:
+///
+/// - `$head` is a valid, initialized sentinel `list_head` (e.g. via `INIT_LIST_HEAD()`)
+/// pointing to a list that is not concurrently modified for the lifetime of the `CList`.
+/// - The list contains items of type `$c_type` linked via an embedded `$field`.
+/// - `$rust_type` is `#[repr(transparent)]` over `$c_type` or has compatible layout.
+///
+/// # Examples
+///
+/// Refer to the examples in this module's documentation.
+#[macro_export]
+macro_rules! clist_create {
+ (unsafe { $head:expr, $rust_type:ty, $c_type:ty, $($field:tt).+ }) => {{
+ // Compile-time check that field path is a list_head.
+ let _: fn(*const $c_type) -> *const $crate::bindings::list_head =
+ |p| unsafe { &raw const (*p).$($field).+ };
+
+ // Calculate offset and create `CList`.
+ const OFFSET: usize = ::core::mem::offset_of!($c_type, $($field).+);
+ // SAFETY: The caller of this macro is responsible for ensuring safety.
+ unsafe { $crate::interop::list::CList::<$rust_type, OFFSET>::from_raw($head) }
+ }};
+}
diff --git a/rust/kernel/interop/mod.rs b/rust/kernel/interop/mod.rs
new file mode 100644
index 000000000000..b88140cf76dc
--- /dev/null
+++ b/rust/kernel/interop/mod.rs
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Infrastructure for interfacing Rust code with C kernel subsystems.
+//!
+//! This module is intended for low-level, unsafe Rust infrastructure code
+//! that interoperates between Rust and C. It is NOT for use directly in
+//! Rust drivers.
+
+pub mod list;
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 3da92f18f4ee..bb741f1e0dfd 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -28,6 +28,7 @@
#![feature(lint_reasons)]
//
// Stable since Rust 1.82.0.
+#![feature(offset_of_nested)]
#![feature(raw_ref_op)]
//
// Stable since Rust 1.83.0.
@@ -103,6 +104,7 @@
#[doc(hidden)]
pub mod impl_flags;
pub mod init;
+pub mod interop;
pub mod io;
pub mod ioctl;
pub mod iommu;
--
2.34.1
^ permalink raw reply related
* [PATCH] staging: sm750fb: add missing const qualifier to char pointer array
From: Oskar Ray-Frayssinet @ 2026-03-07 13:18 UTC (permalink / raw)
To: sudipm.mukherjee, teddy.wang, gregkh
Cc: linux-fbdev, linux-staging, linux-kernel, Oskar Ray-Frayssinet
Add missing 'const' qualifier to g_fbmode pointer array declaration
to make both the pointers and the strings they point to immutable.
Signed-off-by: Oskar Ray-Frayssinet <rayfraytech@gmail.com>
---
drivers/staging/sm750fb/sm750.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/staging/sm750fb/sm750.c b/drivers/staging/sm750fb/sm750.c
index dec1f6b88a7d..08d4979c6755 100644
--- a/drivers/staging/sm750fb/sm750.c
+++ b/drivers/staging/sm750fb/sm750.c
@@ -33,7 +33,7 @@
static int g_hwcursor = 1;
static int g_noaccel;
static int g_nomtrr;
-static const char *g_fbmode[] = {NULL, NULL};
+static const char * const g_fbmode[] = {NULL, NULL};
static const char *g_def_fbmode = "1024x768-32@60";
static char *g_settings;
static int g_dualview;
--
2.43.0
^ permalink raw reply related
* [GIT PULL] fbdev fix for v7.0-rc3
From: Helge Deller @ 2026-03-07 20:44 UTC (permalink / raw)
To: Linus Torvalds, linux-kernel, linux-fbdev, dri-devel
Cc: Uwe Kleine-König
Hi Linus,
please pull one patch for the au1100fb driver to
fix a build error reported by the kernel test robot.
Thanks!
Helge
----------------------------------------------------------------
The following changes since commit 11439c4635edd669ae435eec308f4ab8a0804808:
Linux 7.0-rc2 (2026-03-01 15:39:31 -0800)
are available in the Git repository at:
http://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev.git tags/fbdev-for-7.0-rc3
for you to fetch changes up to e31a374a99f5026df6ebff2a1c49492276e776fd:
fbdev: au1100fb: Fix build on MIPS64 (2026-03-05 17:35:12 +0100)
----------------------------------------------------------------
fbdev fixes for kernel v7.0-rc3:
Silence build error in au1100fb driver found by kernel test robot
----------------------------------------------------------------
Helge Deller (1):
fbdev: au1100fb: Fix build on MIPS64
drivers/video/fbdev/au1100fb.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
^ permalink raw reply
* Re: [GIT PULL] fbdev fix for v7.0-rc3
From: pr-tracker-bot @ 2026-03-07 21:24 UTC (permalink / raw)
To: Helge Deller
Cc: Linus Torvalds, linux-kernel, linux-fbdev, dri-devel,
Uwe Kleine-König
In-Reply-To: <aayOLznDX70UUs6T@carbonx1>
The pull request you sent on Sat, 7 Mar 2026 21:44:31 +0100:
> http://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev.git tags/fbdev-for-7.0-rc3
has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/fb07430e6f98ccff61f6f1a06d01d7f12e29c6d3
Thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/prtracker.html
^ permalink raw reply
page: next (older) | prev (newer) | latest
- recent:[subjects (threaded)|topics (new)|topics (active)]
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox