[Freedreno] [PATCH v5 04/11] PM / QoS: Decouple request alloc from dev_pm_qos_mtx

[Rob Clark]

From: Rob Clark <robdcl...@chromium.org>

Similar to the previous patch, move the allocation out from under
dev_pm_qos_mtx, by speculatively doing the allocation and handle
any race after acquiring dev_pm_qos_mtx by freeing the redundant
allocation.

Signed-off-by: Rob Clark <robdcl...@chromium.org>
---
 drivers/base/power/qos.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index 7e95760d16dc..09834f3354d7 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -930,8 +930,12 @@ s32 dev_pm_qos_get_user_latency_tolerance(struct device 
*dev)
 int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
 {
        struct dev_pm_qos *qos = dev_pm_qos_constraints_allocate(dev);
+       struct dev_pm_qos_request *req = NULL;
        int ret = 0;
 
+       if (!qos->latency_tolerance_req)
+               req = kzalloc(sizeof(*req), GFP_KERNEL);
+
        mutex_lock(&dev_pm_qos_mtx);
 
        dev_pm_qos_constraints_set(dev, qos);
@@ -945,8 +949,6 @@ int dev_pm_qos_update_user_latency_tolerance(struct device 
*dev, s32 val)
                goto out;
 
        if (!dev->power.qos->latency_tolerance_req) {
-               struct dev_pm_qos_request *req;
-
                if (val < 0) {
                        if (val == PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT)
                                ret = 0;
@@ -954,17 +956,15 @@ int dev_pm_qos_update_user_latency_tolerance(struct 
device *dev, s32 val)
                                ret = -EINVAL;
                        goto out;
                }
-               req = kzalloc(sizeof(*req), GFP_KERNEL);
                if (!req) {
                        ret = -ENOMEM;
                        goto out;
                }
                ret = __dev_pm_qos_add_request(dev, req, 
DEV_PM_QOS_LATENCY_TOLERANCE, val);
-               if (ret < 0) {
-                       kfree(req);
+               if (ret < 0)
                        goto out;
-               }
                dev->power.qos->latency_tolerance_req = req;
+               req = NULL;
        } else {
                if (val < 0) {
                        __dev_pm_qos_drop_user_request(dev, 
DEV_PM_QOS_LATENCY_TOLERANCE);
@@ -976,6 +976,7 @@ int dev_pm_qos_update_user_latency_tolerance(struct device 
*dev, s32 val)
 
  out:
        mutex_unlock(&dev_pm_qos_mtx);
+       kfree(req);
        return ret;
 }
 EXPORT_SYMBOL_GPL(dev_pm_qos_update_user_latency_tolerance);
-- 
2.41.0