Re: [PATCH v2 1/6] drm/rockchip: Convert psr_list_mutex to spinlock and use it

On 08/17/2016 09:11 AM, Sean Paul wrote:

This patch converts the psr_list_mutex to a spinlock and locks all access to psr_list to avoid races (however unlikely they were).

Signed-off-by: Sean Paul seanpaul@chromium.org

Reviewed-by: Yakir Yang ykk@rock-chips.com

---

Changes in v2:

• Rebased on https://cgit.freedesktop.org/~seanpaul/dogwood/log/?h=for-next

drivers/gpu/drm/rockchip/rockchip_drm_drv.c | 2 +- drivers/gpu/drm/rockchip/rockchip_drm_drv.h | 2 +- drivers/gpu/drm/rockchip/rockchip_drm_psr.c | 25 ++++++++++++++++++------- 3 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c index b43fe5d9..76eaf1d 100644 --- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c +++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c @@ -157,7 +157,7 @@ static int rockchip_drm_bind(struct device *dev) drm_dev->dev_private = private;

INIT_LIST_HEAD(&private->psr_list);

• mutex_init(&private->psr_list_mutex);

• spin_lock_init(&private->psr_list_lock);

  drm_mode_config_init(drm_dev);

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.h b/drivers/gpu/drm/rockchip/rockchip_drm_drv.h index 9c34c9e..5c69845 100644 --- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.h +++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.h @@ -63,7 +63,7 @@ struct rockchip_drm_private { struct drm_atomic_state *state;

struct list_head psr_list;

• struct mutex psr_list_mutex;

• spinlock_t psr_list_lock; };

  int rockchip_register_crtc_funcs(struct drm_crtc *crtc,

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_psr.c b/drivers/gpu/drm/rockchip/rockchip_drm_psr.c index a6d3bd25..bd25273 100644 --- a/drivers/gpu/drm/rockchip/rockchip_drm_psr.c +++ b/drivers/gpu/drm/rockchip/rockchip_drm_psr.c @@ -45,12 +45,18 @@ static struct psr_drv *find_psr_by_crtc(struct drm_crtc *crtc) { struct rockchip_drm_private *drm_drv = crtc->dev->dev_private; struct psr_drv *psr;

• unsigned long flags;

• list_for_each_entry(psr, &drm_drv->psr_list, list)

• spin_lock_irqsave(&drm_drv->psr_list_lock, flags);
• list_for_each_entry(psr, &drm_drv->psr_list, list) { if (psr->encoder->crtc == crtc)

• 	return psr;
  

• 	goto out;
  

• }
• psr = ERR_PTR(-ENODEV);

• return ERR_PTR(-ENODEV);

+out:

• spin_unlock_irqrestore(&drm_drv->psr_list_lock, flags);

• return psr; }

  static void psr_state_work(struct work_struct *work)

@@ -173,7 +179,9 @@ void rockchip_drm_psr_flush(struct drm_device *dev) { struct rockchip_drm_private *drm_drv = dev->dev_private; struct psr_drv *psr;

• unsigned long flags;

• spin_lock_irqsave(&drm_drv->psr_list_lock, flags); list_for_each_entry(psr, &drm_drv->psr_list, list) { if (psr->request_state == PSR_DISABLE) continue;

@@ -183,6 +191,7 @@ void rockchip_drm_psr_flush(struct drm_device *dev)

psr_set_state(psr, PSR_FLUSH);

}

• spin_unlock_irqrestore(&drm_drv->psr_list_lock, flags); } EXPORT_SYMBOL(rockchip_drm_psr_flush);

@@ -199,6 +208,7 @@ int rockchip_drm_psr_register(struct drm_encoder *encoder, { struct rockchip_drm_private *drm_drv = encoder->dev->dev_private; struct psr_drv *psr;

• unsigned long flags;

  if (!encoder || !psr_set) return -EINVAL;

@@ -215,9 +225,9 @@ int rockchip_drm_psr_register(struct drm_encoder *encoder, psr->encoder = encoder; psr->set = psr_set;

• mutex_lock(&drm_drv->psr_list_mutex);

• spin_lock_irqsave(&drm_drv->psr_list_lock, flags); list_add_tail(&psr->list, &drm_drv->psr_list);

• mutex_unlock(&drm_drv->psr_list_mutex);

• spin_unlock_irqrestore(&drm_drv->psr_list_lock, flags);

  return 0; }

@@ -235,8 +245,9 @@ void rockchip_drm_psr_unregister(struct drm_encoder *encoder) { struct rockchip_drm_private *drm_drv = encoder->dev->dev_private; struct psr_drv *psr, *n;

• unsigned long flags;

• mutex_lock(&drm_drv->psr_list_mutex);

• spin_lock_irqsave(&drm_drv->psr_list_lock, flags); list_for_each_entry_safe(psr, n, &drm_drv->psr_list, list) { if (psr->encoder == encoder) { del_timer(&psr->flush_timer);

@@ -244,6 +255,6 @@ void rockchip_drm_psr_unregister(struct drm_encoder *encoder) kfree(psr); } }

• mutex_unlock(&drm_drv->psr_list_mutex);

• spin_unlock_irqrestore(&drm_drv->psr_list_lock, flags); } EXPORT_SYMBOL(rockchip_drm_psr_unregister);