Re: [PATCH -V2] drm/sun4i: Grab reference of connector before return connector from sun4i_tcon_get_connector
在 2021/11/2 23:03, Maxime Ripard 写道:
Hi,
On Tue, Nov 02, 2021 at 04:46:28AM -0400, He Ying wrote:
From the comments of drm_for_each_connector_iter(), we know
that "connector is only valid within the list body, if you
want to use connector after calling drm_connector_list_iter_end()
then you need to grab your own reference first using
drm_connector_get()". So fix the wrong use of connector
according to the comments and then call drm_connector_put()
after using connector finishes.
Signed-off-by: He Ying
---
V2:
Use proper subject prefix
drivers/gpu/drm/sun4i/sun4i_tcon.c | 18 +-
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c
b/drivers/gpu/drm/sun4i/sun4i_tcon.c
index 9f06dec0fc61..24fa6784ee5f 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -47,12 +47,12 @@ static struct drm_connector *sun4i_tcon_get_connector(const
struct drm_encoder *
drm_connector_list_iter_begin(encoder->dev, );
drm_for_each_connector_iter(connector, )
if (connector->encoder == encoder) {
- drm_connector_list_iter_end();
- return connector;
+ drm_connector_get(connector);
+ break;
}
drm_connector_list_iter_end();
- return NULL;
+ return connector;
Connector might be uninitialized if we don't find one here
Connector should be NULL if we don't find one. The code is
#define drm_for_each_connector_iter(connector, iter) \
while ((connector = drm_connector_list_iter_next(iter)))
So, when we don't break from the while body, connector
can only be NULL.
}
static int sun4i_tcon_get_pixel_depth(const struct drm_encoder *encoder)
@@ -65,6 +65,7 @@ static int sun4i_tcon_get_pixel_depth(const struct
drm_encoder *encoder)
return -EINVAL;
info = >display_info;
+ drm_connector_put(connector);
if (info->num_bus_formats != 1)
We're still accessing connector->display_info here, but it might have been
freed already.
Agree. I'll place it after using 'info' finishes in v3.
Maxime
Re: [PATCH -V2] drm/sun4i: Grab reference of connector before return connector from sun4i_tcon_get_connector
Hi,
On Tue, Nov 02, 2021 at 04:46:28AM -0400, He Ying wrote:
> From the comments of drm_for_each_connector_iter(), we know
> that "connector is only valid within the list body, if you
> want to use connector after calling drm_connector_list_iter_end()
> then you need to grab your own reference first using
> drm_connector_get()". So fix the wrong use of connector
> according to the comments and then call drm_connector_put()
> after using connector finishes.
>
> Signed-off-by: He Ying
> ---
>
> V2:
> Use proper subject prefix
>
> drivers/gpu/drm/sun4i/sun4i_tcon.c | 18 +-
> 1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c
> b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> index 9f06dec0fc61..24fa6784ee5f 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> @@ -47,12 +47,12 @@ static struct drm_connector
> *sun4i_tcon_get_connector(const struct drm_encoder *
> drm_connector_list_iter_begin(encoder->dev, );
> drm_for_each_connector_iter(connector, )
> if (connector->encoder == encoder) {
> - drm_connector_list_iter_end();
> - return connector;
> + drm_connector_get(connector);
> + break;
> }
> drm_connector_list_iter_end();
>
> - return NULL;
> + return connector;
Connector might be uninitialized if we don't find one here
> }
>
> static int sun4i_tcon_get_pixel_depth(const struct drm_encoder *encoder)
> @@ -65,6 +65,7 @@ static int sun4i_tcon_get_pixel_depth(const struct
> drm_encoder *encoder)
> return -EINVAL;
>
> info = >display_info;
> + drm_connector_put(connector);
> if (info->num_bus_formats != 1)
We're still accessing connector->display_info here, but it might have been
freed already.
Maxime
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[PATCH -V2] drm/sun4i: Grab reference of connector before return connector from sun4i_tcon_get_connector
>From the comments of drm_for_each_connector_iter(), we know
that "connector is only valid within the list body, if you
want to use connector after calling drm_connector_list_iter_end()
then you need to grab your own reference first using
drm_connector_get()". So fix the wrong use of connector
according to the comments and then call drm_connector_put()
after using connector finishes.
Signed-off-by: He Ying
---
V2:
Use proper subject prefix
drivers/gpu/drm/sun4i/sun4i_tcon.c | 18 +-
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c
b/drivers/gpu/drm/sun4i/sun4i_tcon.c
index 9f06dec0fc61..24fa6784ee5f 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -47,12 +47,12 @@ static struct drm_connector *sun4i_tcon_get_connector(const
struct drm_encoder *
drm_connector_list_iter_begin(encoder->dev, );
drm_for_each_connector_iter(connector, )
if (connector->encoder == encoder) {
- drm_connector_list_iter_end();
- return connector;
+ drm_connector_get(connector);
+ break;
}
drm_connector_list_iter_end();
- return NULL;
+ return connector;
}
static int sun4i_tcon_get_pixel_depth(const struct drm_encoder *encoder)
@@ -65,6 +65,7 @@ static int sun4i_tcon_get_pixel_depth(const struct
drm_encoder *encoder)
return -EINVAL;
info = >display_info;
+ drm_connector_put(connector);
if (info->num_bus_formats != 1)
return -EINVAL;
@@ -361,6 +362,7 @@ static void sun4i_tcon0_mode_set_cpu(struct sun4i_tcon
*tcon,
/* TODO support normal CPU interface modes */
struct sun6i_dsi *dsi = encoder_to_sun6i_dsi(encoder);
struct mipi_dsi_device *device = dsi->device;
+ struct drm_connector *connector;
u8 bpp = mipi_dsi_pixel_format_to_bpp(device->format);
u8 lanes = device->lanes;
u32 block_space, start_delay;
@@ -372,7 +374,9 @@ static void sun4i_tcon0_mode_set_cpu(struct sun4i_tcon
*tcon,
sun4i_tcon0_mode_set_common(tcon, mode);
/* Set dithering if needed */
- sun4i_tcon0_mode_set_dithering(tcon, sun4i_tcon_get_connector(encoder));
+ connector = sun4i_tcon_get_connector(encoder);
+ sun4i_tcon0_mode_set_dithering(tcon, connector);
+ drm_connector_put(connector);
regmap_update_bits(tcon->regs, SUN4I_TCON0_CTL_REG,
SUN4I_TCON0_CTL_IF_MASK,
@@ -430,6 +434,7 @@ static void sun4i_tcon0_mode_set_lvds(struct sun4i_tcon
*tcon,
const struct drm_display_mode *mode)
{
unsigned int bp;
+ struct drm_connector *connector;
u8 clk_delay;
u32 reg, val = 0;
@@ -440,7 +445,9 @@ static void sun4i_tcon0_mode_set_lvds(struct sun4i_tcon
*tcon,
sun4i_tcon0_mode_set_common(tcon, mode);
/* Set dithering if needed */
- sun4i_tcon0_mode_set_dithering(tcon, sun4i_tcon_get_connector(encoder));
+ connector = sun4i_tcon_get_connector(encoder);
+ sun4i_tcon0_mode_set_dithering(tcon, connector);
+ drm_connector_put(connector);
/* Adjust clock delay */
clk_delay = sun4i_tcon_get_clk_delay(mode, 0);
@@ -518,6 +525,7 @@ static void sun4i_tcon0_mode_set_rgb(struct sun4i_tcon
*tcon,
/* Set dithering if needed */
sun4i_tcon0_mode_set_dithering(tcon, connector);
+ drm_connector_put(connector);
/* Adjust clock delay */
clk_delay = sun4i_tcon_get_clk_delay(mode, 0);
--
2.17.1
