Hi Sean,

Thank you for the patch.

On Fri, Feb 07, 2025 at 11:25:28AM -0500, Sean Anderson wrote:
> Convert most mutex_(un)lock calls to use (scoped_)guard instead. This
> generally reduces line count and prevents bugs like forgetting to unlock
> the mutex. I've left traditional calls in a few places where scoped
> helpers would be more verbose. This mostly happens where
> debugfs_file_put needs to be called regardless. I looked into defining a
> CLASS for debugfs_file, but it seems like more effort than it's worth
> since debugfs_file_get can fail.
> 
> Signed-off-by: Sean Anderson <[email protected]>
> ---
> 
> Changes in v2:
> - Convert some conditional return statements to returns of ternary
>   expressions.
> - Remove unnecessary whitespace change
> 
>  drivers/gpu/drm/xlnx/zynqmp_dp.c | 147 +++++++++++--------------------
>  1 file changed, 50 insertions(+), 97 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c 
> b/drivers/gpu/drm/xlnx/zynqmp_dp.c
> index 189a08cdc73c..63842f657836 100644
> --- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
> +++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
> @@ -1534,10 +1534,10 @@ zynqmp_dp_bridge_mode_valid(struct drm_bridge *bridge,
>       }
>  
>       /* Check with link rate and lane count */
> -     mutex_lock(&dp->lock);
> -     rate = zynqmp_dp_max_rate(dp->link_config.max_rate,
> -                               dp->link_config.max_lanes, dp->config.bpp);
> -     mutex_unlock(&dp->lock);
> +     scoped_guard(mutex, &dp->lock)
> +             rate = zynqmp_dp_max_rate(dp->link_config.max_rate,
> +                                       dp->link_config.max_lanes,
> +                                       dp->config.bpp);

Could we use curly braces even for single-statement scopes ?

        scoped_guard(mutex, &dp->lock) {
                rate = zynqmp_dp_max_rate(dp->link_config.max_rate,
                                          dp->link_config.max_lanes,
                                          dp->config.bpp);
        }

I think this would make the scope clearer.

Reviewed-by: Laurent Pinchart <[email protected]>

>       if (mode->clock > rate) {
>               dev_dbg(dp->dev, "filtered mode %s for high pixel rate\n",
>                       mode->name);
> @@ -1722,13 +1722,9 @@ static enum drm_connector_status 
> __zynqmp_dp_bridge_detect(struct zynqmp_dp *dp)
>  static enum drm_connector_status zynqmp_dp_bridge_detect(struct drm_bridge 
> *bridge)
>  {
>       struct zynqmp_dp *dp = bridge_to_dp(bridge);
> -     enum drm_connector_status ret;
>  
> -     mutex_lock(&dp->lock);
> -     ret = __zynqmp_dp_bridge_detect(dp);
> -     mutex_unlock(&dp->lock);
> -
> -     return ret;
> +     guard(mutex)(&dp->lock);
> +     return __zynqmp_dp_bridge_detect(dp);
>  }
>  
>  static const struct drm_edid *zynqmp_dp_bridge_edid_read(struct drm_bridge 
> *bridge,
> @@ -1881,10 +1877,9 @@ static ssize_t zynqmp_dp_pattern_read(struct file 
> *file, char __user *user_buf,
>       if (unlikely(ret))
>               return ret;
>  
> -     mutex_lock(&dp->lock);
> -     ret = snprintf(buf, sizeof(buf), "%s\n",
> -                    test_pattern_str[dp->test.pattern]);
> -     mutex_unlock(&dp->lock);
> +     scoped_guard(mutex, &dp->lock)
> +             ret = snprintf(buf, sizeof(buf), "%s\n",
> +                            test_pattern_str[dp->test.pattern]);
>  
>       debugfs_file_put(dentry);
>       return simple_read_from_buffer(user_buf, count, ppos, buf, ret);
> @@ -1939,24 +1934,18 @@ static int zynqmp_dp_enhanced_get(void *data, u64 
> *val)
>  {
>       struct zynqmp_dp *dp = data;
>  
> -     mutex_lock(&dp->lock);
> +     guard(mutex)(&dp->lock);
>       *val = dp->test.enhanced;
> -     mutex_unlock(&dp->lock);
>       return 0;
>  }
>  
>  static int zynqmp_dp_enhanced_set(void *data, u64 val)
>  {
>       struct zynqmp_dp *dp = data;
> -     int ret = 0;
>  
> -     mutex_lock(&dp->lock);
> +     guard(mutex)(&dp->lock);
>       dp->test.enhanced = val;
> -     if (dp->test.active)
> -             ret = zynqmp_dp_test_setup(dp);
> -     mutex_unlock(&dp->lock);
> -
> -     return ret;
> +     return dp->test.active ? zynqmp_dp_test_setup(dp) : 0;
>  }
>  
>  DEFINE_DEBUGFS_ATTRIBUTE(fops_zynqmp_dp_enhanced, zynqmp_dp_enhanced_get,
> @@ -1966,24 +1955,19 @@ static int zynqmp_dp_downspread_get(void *data, u64 
> *val)
>  {
>       struct zynqmp_dp *dp = data;
>  
> -     mutex_lock(&dp->lock);
> +     guard(mutex)(&dp->lock);
>       *val = dp->test.downspread;
> -     mutex_unlock(&dp->lock);
>       return 0;
>  }
>  
>  static int zynqmp_dp_downspread_set(void *data, u64 val)
>  {
>       struct zynqmp_dp *dp = data;
> -     int ret = 0;
>  
> -     mutex_lock(&dp->lock);
> +     guard(mutex)(&dp->lock);
>       dp->test.downspread = val;
> -     if (dp->test.active)
> -             ret = zynqmp_dp_test_setup(dp);
> -     mutex_unlock(&dp->lock);
>  
> -     return ret;
> +     return dp->test.active ? zynqmp_dp_test_setup(dp) : 0;
>  }
>  
>  DEFINE_DEBUGFS_ATTRIBUTE(fops_zynqmp_dp_downspread, zynqmp_dp_downspread_get,
> @@ -1993,33 +1977,32 @@ static int zynqmp_dp_active_get(void *data, u64 *val)
>  {
>       struct zynqmp_dp *dp = data;
>  
> -     mutex_lock(&dp->lock);
> +     guard(mutex)(&dp->lock);
>       *val = dp->test.active;
> -     mutex_unlock(&dp->lock);
>       return 0;
>  }
>  
>  static int zynqmp_dp_active_set(void *data, u64 val)
>  {
>       struct zynqmp_dp *dp = data;
> -     int ret = 0;
> +     int ret;
>  
> -     mutex_lock(&dp->lock);
> +     guard(mutex)(&dp->lock);
>       if (val) {
>               if (val < 2) {
>                       ret = zynqmp_dp_test_setup(dp);
>                       if (ret)
> -                             goto out;
> +                             return ret;
>               }
>  
>               ret = zynqmp_dp_set_test_pattern(dp, dp->test.pattern,
>                                                dp->test.custom);
>               if (ret)
> -                     goto out;
> +                     return ret;
>  
>               ret = zynqmp_dp_update_vs_emph(dp, dp->test.train_set);
>               if (ret)
> -                     goto out;
> +                     return ret;
>  
>               dp->test.active = true;
>       } else {
> @@ -2032,10 +2015,8 @@ static int zynqmp_dp_active_set(void *data, u64 val)
>                                err);
>               zynqmp_dp_train_loop(dp);
>       }
> -out:
> -     mutex_unlock(&dp->lock);
>  
> -     return ret;
> +     return 0;
>  }
>  
>  DEFINE_DEBUGFS_ATTRIBUTE(fops_zynqmp_dp_active, zynqmp_dp_active_get,
> @@ -2102,9 +2083,8 @@ static int zynqmp_dp_swing_get(void *data, u64 *val)
>       struct zynqmp_dp_train_set_priv *priv = data;
>       struct zynqmp_dp *dp = priv->dp;
>  
> -     mutex_lock(&dp->lock);
> +     guard(mutex)(&dp->lock);
>       *val = dp->test.train_set[priv->lane] & DP_TRAIN_VOLTAGE_SWING_MASK;
> -     mutex_unlock(&dp->lock);
>       return 0;
>  }
>  
> @@ -2113,12 +2093,11 @@ static int zynqmp_dp_swing_set(void *data, u64 val)
>       struct zynqmp_dp_train_set_priv *priv = data;
>       struct zynqmp_dp *dp = priv->dp;
>       u8 *train_set = &dp->test.train_set[priv->lane];
> -     int ret = 0;
>  
>       if (val > 3)
>               return -EINVAL;
>  
> -     mutex_lock(&dp->lock);
> +     guard(mutex)(&dp->lock);
>       *train_set &= ~(DP_TRAIN_MAX_SWING_REACHED |
>                       DP_TRAIN_VOLTAGE_SWING_MASK);
>       *train_set |= val;
> @@ -2126,10 +2105,9 @@ static int zynqmp_dp_swing_set(void *data, u64 val)
>               *train_set |= DP_TRAIN_MAX_SWING_REACHED;
>  
>       if (dp->test.active)
> -             ret = zynqmp_dp_update_vs_emph(dp, dp->test.train_set);
> -     mutex_unlock(&dp->lock);
> +             return zynqmp_dp_update_vs_emph(dp, dp->test.train_set);
>  
> -     return ret;
> +     return 0;
>  }
>  
>  DEFINE_DEBUGFS_ATTRIBUTE(fops_zynqmp_dp_swing, zynqmp_dp_swing_get,
> @@ -2140,10 +2118,9 @@ static int zynqmp_dp_preemphasis_get(void *data, u64 
> *val)
>       struct zynqmp_dp_train_set_priv *priv = data;
>       struct zynqmp_dp *dp = priv->dp;
>  
> -     mutex_lock(&dp->lock);
> +     guard(mutex)(&dp->lock);
>       *val = FIELD_GET(DP_TRAIN_PRE_EMPHASIS_MASK,
>                        dp->test.train_set[priv->lane]);
> -     mutex_unlock(&dp->lock);
>       return 0;
>  }
>  
> @@ -2152,12 +2129,11 @@ static int zynqmp_dp_preemphasis_set(void *data, u64 
> val)
>       struct zynqmp_dp_train_set_priv *priv = data;
>       struct zynqmp_dp *dp = priv->dp;
>       u8 *train_set = &dp->test.train_set[priv->lane];
> -     int ret = 0;
>  
>       if (val > 2)
>               return -EINVAL;
>  
> -     mutex_lock(&dp->lock);
> +     guard(mutex)(&dp->lock);
>       *train_set &= ~(DP_TRAIN_MAX_PRE_EMPHASIS_REACHED |
>                       DP_TRAIN_PRE_EMPHASIS_MASK);
>       *train_set |= val;
> @@ -2165,10 +2141,9 @@ static int zynqmp_dp_preemphasis_set(void *data, u64 
> val)
>               *train_set |= DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
>  
>       if (dp->test.active)
> -             ret = zynqmp_dp_update_vs_emph(dp, dp->test.train_set);
> -     mutex_unlock(&dp->lock);
> +             return zynqmp_dp_update_vs_emph(dp, dp->test.train_set);
>  
> -     return ret;
> +     return 0;
>  }
>  
>  DEFINE_DEBUGFS_ATTRIBUTE(fops_zynqmp_dp_preemphasis, 
> zynqmp_dp_preemphasis_get,
> @@ -2178,31 +2153,24 @@ static int zynqmp_dp_lanes_get(void *data, u64 *val)
>  {
>       struct zynqmp_dp *dp = data;
>  
> -     mutex_lock(&dp->lock);
> +     guard(mutex)(&dp->lock);
>       *val = dp->test.link_cnt;
> -     mutex_unlock(&dp->lock);
>       return 0;
>  }
>  
>  static int zynqmp_dp_lanes_set(void *data, u64 val)
>  {
>       struct zynqmp_dp *dp = data;
> -     int ret = 0;
>  
>       if (val > ZYNQMP_DP_MAX_LANES)
>               return -EINVAL;
>  
> -     mutex_lock(&dp->lock);
> -     if (val > dp->num_lanes) {
> -             ret = -EINVAL;
> -     } else {
> -             dp->test.link_cnt = val;
> -             if (dp->test.active)
> -                     ret = zynqmp_dp_test_setup(dp);
> -     }
> -     mutex_unlock(&dp->lock);
> +     guard(mutex)(&dp->lock);
> +     if (val > dp->num_lanes)
> +             return -EINVAL;
>  
> -     return ret;
> +     dp->test.link_cnt = val;
> +     return dp->test.active ? zynqmp_dp_test_setup(dp) : 0;
>  }
>  
>  DEFINE_DEBUGFS_ATTRIBUTE(fops_zynqmp_dp_lanes, zynqmp_dp_lanes_get,
> @@ -2212,9 +2180,8 @@ static int zynqmp_dp_rate_get(void *data, u64 *val)
>  {
>       struct zynqmp_dp *dp = data;
>  
> -     mutex_lock(&dp->lock);
> +     guard(mutex)(&dp->lock);
>       *val = drm_dp_bw_code_to_link_rate(dp->test.bw_code) * 10000ULL;
> -     mutex_unlock(&dp->lock);
>       return 0;
>  }
>  
> @@ -2222,7 +2189,6 @@ static int zynqmp_dp_rate_set(void *data, u64 val)
>  {
>       struct zynqmp_dp *dp = data;
>       int link_rate;
> -     int ret = 0;
>       u8 bw_code;
>  
>       if (do_div(val, 10000))
> @@ -2237,13 +2203,9 @@ static int zynqmp_dp_rate_set(void *data, u64 val)
>           bw_code != DP_LINK_BW_5_4)
>               return -EINVAL;
>  
> -     mutex_lock(&dp->lock);
> +     guard(mutex)(&dp->lock);
>       dp->test.bw_code = bw_code;
> -     if (dp->test.active)
> -             ret = zynqmp_dp_test_setup(dp);
> -     mutex_unlock(&dp->lock);
> -
> -     return ret;
> +     return dp->test.active ? zynqmp_dp_test_setup(dp) : 0;
>  }
>  
>  DEFINE_DEBUGFS_ATTRIBUTE(fops_zynqmp_dp_rate, zynqmp_dp_rate_get,
> @@ -2253,9 +2215,8 @@ static int zynqmp_dp_ignore_aux_errors_get(void *data, 
> u64 *val)
>  {
>       struct zynqmp_dp *dp = data;
>  
> -     mutex_lock(&dp->aux.hw_mutex);
> +     guard(mutex)(&dp->lock);
>       *val = dp->ignore_aux_errors;
> -     mutex_unlock(&dp->aux.hw_mutex);
>       return 0;
>  }
>  
> @@ -2266,9 +2227,8 @@ static int zynqmp_dp_ignore_aux_errors_set(void *data, 
> u64 val)
>       if (val != !!val)
>               return -EINVAL;
>  
> -     mutex_lock(&dp->aux.hw_mutex);
> +     guard(mutex)(&dp->lock);
>       dp->ignore_aux_errors = val;
> -     mutex_unlock(&dp->aux.hw_mutex);
>       return 0;
>  }
>  
> @@ -2280,9 +2240,8 @@ static int zynqmp_dp_ignore_hpd_get(void *data, u64 
> *val)
>  {
>       struct zynqmp_dp *dp = data;
>  
> -     mutex_lock(&dp->lock);
> +     guard(mutex)(&dp->lock);
>       *val = dp->ignore_hpd;
> -     mutex_unlock(&dp->lock);
>       return 0;
>  }
>  
> @@ -2293,9 +2252,8 @@ static int zynqmp_dp_ignore_hpd_set(void *data, u64 val)
>       if (val != !!val)
>               return -EINVAL;
>  
> -     mutex_lock(&dp->lock);
> +     guard(mutex)(&dp->lock);
>       dp->ignore_hpd = val;
> -     mutex_unlock(&dp->lock);
>       return 0;
>  }
>  
> @@ -2391,14 +2349,12 @@ static void zynqmp_dp_hpd_work_func(struct 
> work_struct *work)
>       struct zynqmp_dp *dp = container_of(work, struct zynqmp_dp, hpd_work);
>       enum drm_connector_status status;
>  
> -     mutex_lock(&dp->lock);
> -     if (dp->ignore_hpd) {
> -             mutex_unlock(&dp->lock);
> -             return;
> -     }
> +     scoped_guard(mutex, &dp->lock) {
> +             if (dp->ignore_hpd)
> +                     return;
>  
> -     status = __zynqmp_dp_bridge_detect(dp);
> -     mutex_unlock(&dp->lock);
> +             status = __zynqmp_dp_bridge_detect(dp);
> +     }
>  
>       drm_bridge_hpd_notify(&dp->bridge, status);
>  }
> @@ -2410,11 +2366,9 @@ static void zynqmp_dp_hpd_irq_work_func(struct 
> work_struct *work)
>       u8 status[DP_LINK_STATUS_SIZE + 2];
>       int err;
>  
> -     mutex_lock(&dp->lock);
> -     if (dp->ignore_hpd) {
> -             mutex_unlock(&dp->lock);
> +     guard(mutex)(&dp->lock);
> +     if (dp->ignore_hpd)
>               return;
> -     }
>  
>       err = drm_dp_dpcd_read(&dp->aux, DP_SINK_COUNT, status,
>                              DP_LINK_STATUS_SIZE + 2);
> @@ -2428,7 +2382,6 @@ static void zynqmp_dp_hpd_irq_work_func(struct 
> work_struct *work)
>                       zynqmp_dp_train_loop(dp);
>               }
>       }
> -     mutex_unlock(&dp->lock);
>  }
>  
>  static irqreturn_t zynqmp_dp_irq_handler(int irq, void *data)

-- 
Regards,

Laurent Pinchart

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