| Message ID | 20200807111153.7784-7-tingwei@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | coresight: allow to build coresight as modules | expand |
On Fri, Aug 07, 2020 at 07:11:35PM +0800, Tingwei Zhang wrote: > When coresight device is in an active session, driver module of > that device should not be removed. Use try_get_module() in > coresight_grab_device() to prevent module to be unloaded. > Use get_device()/put_device() to protect device data > in the middle of active session. > > Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org> > Tested-by: Mike Leach <mike.leach@linaro.org> > Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com> > --- > drivers/hwtracing/coresight/coresight.c | 61 ++++++++++++++++++++++--- > 1 file changed, 54 insertions(+), 7 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c > index b7151c5f81b1..0b0e31577b9b 100644 > --- a/drivers/hwtracing/coresight/coresight.c > +++ b/drivers/hwtracing/coresight/coresight.c > @@ -634,13 +634,45 @@ struct coresight_device *coresight_get_sink_by_id(u32 id) > return dev ? to_coresight_device(dev) : NULL; > } > > +/** > + * coresight_get_ref- Helper function to increase reference count to module > + * and device. > + * Return true in successful case and power up the device. > + * Return false when failed to get reference of module. > + */ > +static inline bool coresight_get_ref(struct coresight_device *csdev) > +{ > + struct device *dev = csdev->dev.parent; > + > + /* Make sure the driver can't be removed */ > + if (!try_module_get(dev->driver->owner)) > + return false; > + /* Make sure the device can't go away */ > + get_device(dev); > + pm_runtime_get_sync(dev); > + return true; > +} > + > +/** > + * coresight_put_ref- Helper function to decrease reference count to module > + * and device. Power off the device. > + */ > +static inline void coresight_put_ref(struct coresight_device *csdev) > +{ > + struct device *dev = csdev->dev.parent; > + > + pm_runtime_put(dev); > + put_device(dev); > + module_put(dev->driver->owner); > +} > + > /* > * coresight_grab_device - Power up this device and any of the helper > * devices connected to it for trace operation. Since the helper devices > * don't appear on the trace path, they should be handled along with the > * the master device. > */ > -static void coresight_grab_device(struct coresight_device *csdev) > +static int coresight_grab_device(struct coresight_device *csdev) > { > int i; > > @@ -649,9 +681,20 @@ static void coresight_grab_device(struct coresight_device *csdev) > > child = csdev->pdata->conns[i].child_dev; > if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) > - pm_runtime_get_sync(child->dev.parent); > + if (!coresight_get_ref(child)) > + goto err; > + } > + if (coresight_get_ref(csdev)) > + return 0; > +err: > + for (i--; i >= 0; i--) { > + struct coresight_device *child; > + > + child = csdev->pdata->conns[i].child_dev; > + if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) > + coresight_put_ref(child); > } > - pm_runtime_get_sync(csdev->dev.parent); > + return -ENODEV; > } > > /* > @@ -662,13 +705,13 @@ static void coresight_drop_device(struct coresight_device *csdev) > { > int i; > > - pm_runtime_put(csdev->dev.parent); > + coresight_put_ref(csdev); > for (i = 0; i < csdev->pdata->nr_outport; i++) { > struct coresight_device *child; > > child = csdev->pdata->conns[i].child_dev; > if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) > - pm_runtime_put(child->dev.parent); > + coresight_put_ref(child); > } > } > > @@ -687,7 +730,7 @@ static int _coresight_build_path(struct coresight_device *csdev, > struct coresight_device *sink, > struct list_head *path) > { > - int i; > + int i, ret; > bool found = false; > struct coresight_node *node; > > @@ -721,7 +764,11 @@ static int _coresight_build_path(struct coresight_device *csdev, > if (!node) > return -ENOMEM; > > - coresight_grab_device(csdev); > + ret = coresight_grab_device(csdev); I suggest trying to grab the device before allocating memory for the node. If grabing the device fails memory doesn't have to be allocated and released needlessly. I will likely come back to this patch later after reviewing the rest the this set. Thanks, Mathieu > + if (ret) { > + kfree(node); > + return ret; > + } > node->csdev = csdev; > list_add(&node->link, path); > > -- > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project >
On Thu, Aug 13, 2020 at 03:36:12AM +0800, Mathieu Poirier wrote: > On Fri, Aug 07, 2020 at 07:11:35PM +0800, Tingwei Zhang wrote: > > When coresight device is in an active session, driver module of > > that device should not be removed. Use try_get_module() in > > coresight_grab_device() to prevent module to be unloaded. > > Use get_device()/put_device() to protect device data > > in the middle of active session. > > > > Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org> > > Tested-by: Mike Leach <mike.leach@linaro.org> > > Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com> > > --- > > drivers/hwtracing/coresight/coresight.c | 61 ++++++++++++++++++++++--- > > 1 file changed, 54 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/hwtracing/coresight/coresight.c > b/drivers/hwtracing/coresight/coresight.c > > index b7151c5f81b1..0b0e31577b9b 100644 > > --- a/drivers/hwtracing/coresight/coresight.c > > +++ b/drivers/hwtracing/coresight/coresight.c > > @@ -634,13 +634,45 @@ struct coresight_device > *coresight_get_sink_by_id(u32 id) > > return dev ? to_coresight_device(dev) : NULL; > > } > > > > +/** > > + * coresight_get_ref- Helper function to increase reference count to > module > > + * and device. > > + * Return true in successful case and power up the device. > > + * Return false when failed to get reference of module. > > + */ > > +static inline bool coresight_get_ref(struct coresight_device *csdev) > > +{ > > + struct device *dev = csdev->dev.parent; > > + > > + /* Make sure the driver can't be removed */ > > + if (!try_module_get(dev->driver->owner)) > > + return false; > > + /* Make sure the device can't go away */ > > + get_device(dev); > > + pm_runtime_get_sync(dev); > > + return true; > > +} > > + > > +/** > > + * coresight_put_ref- Helper function to decrease reference count to > module > > + * and device. Power off the device. > > + */ > > +static inline void coresight_put_ref(struct coresight_device *csdev) > > +{ > > + struct device *dev = csdev->dev.parent; > > + > > + pm_runtime_put(dev); > > + put_device(dev); > > + module_put(dev->driver->owner); > > +} > > + > > /* > > * coresight_grab_device - Power up this device and any of the helper > > * devices connected to it for trace operation. Since the helper > devices > > * don't appear on the trace path, they should be handled along with > the > > * the master device. > > */ > > -static void coresight_grab_device(struct coresight_device *csdev) > > +static int coresight_grab_device(struct coresight_device *csdev) > > { > > int i; > > > > @@ -649,9 +681,20 @@ static void coresight_grab_device(struct > coresight_device *csdev) > > > > child = csdev->pdata->conns[i].child_dev; > > if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) > > - pm_runtime_get_sync(child->dev.parent); > > + if (!coresight_get_ref(child)) > > + goto err; > > + } > > + if (coresight_get_ref(csdev)) > > + return 0; > > +err: > > + for (i--; i >= 0; i--) { > > + struct coresight_device *child; > > + > > + child = csdev->pdata->conns[i].child_dev; > > + if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) > > + coresight_put_ref(child); > > } > > - pm_runtime_get_sync(csdev->dev.parent); > > + return -ENODEV; > > } > > > > /* > > @@ -662,13 +705,13 @@ static void coresight_drop_device(struct > coresight_device *csdev) > > { > > int i; > > > > - pm_runtime_put(csdev->dev.parent); > > + coresight_put_ref(csdev); > > for (i = 0; i < csdev->pdata->nr_outport; i++) { > > struct coresight_device *child; > > > > child = csdev->pdata->conns[i].child_dev; > > if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) > > - pm_runtime_put(child->dev.parent); > > + coresight_put_ref(child); > > } > > } > > > > @@ -687,7 +730,7 @@ static int _coresight_build_path(struct > coresight_device *csdev, > > struct coresight_device *sink, > > struct list_head *path) > > { > > - int i; > > + int i, ret; > > bool found = false; > > struct coresight_node *node; > > > > @@ -721,7 +764,11 @@ static int _coresight_build_path(struct > coresight_device *csdev, > > if (!node) > > return -ENOMEM; > > > > - coresight_grab_device(csdev); > > + ret = coresight_grab_device(csdev); > > I suggest trying to grab the device before allocating memory for the node. > If > grabing the device fails memory doesn't have to be allocated and released > needlessly. > Agree. I'll fix in next revision. Thanks, Tingwei > I will likely come back to this patch later after reviewing the rest the > this > set. > > Thanks, > Mathieu > > > + if (ret) { > > + kfree(node); > > + return ret; > > + } > > node->csdev = csdev; > > list_add(&node->link, path); > > > > -- > > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora > Forum, > > a Linux Foundation Collaborative Project > >
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index b7151c5f81b1..0b0e31577b9b 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -634,13 +634,45 @@ struct coresight_device *coresight_get_sink_by_id(u32 id) return dev ? to_coresight_device(dev) : NULL; } +/** + * coresight_get_ref- Helper function to increase reference count to module + * and device. + * Return true in successful case and power up the device. + * Return false when failed to get reference of module. + */ +static inline bool coresight_get_ref(struct coresight_device *csdev) +{ + struct device *dev = csdev->dev.parent; + + /* Make sure the driver can't be removed */ + if (!try_module_get(dev->driver->owner)) + return false; + /* Make sure the device can't go away */ + get_device(dev); + pm_runtime_get_sync(dev); + return true; +} + +/** + * coresight_put_ref- Helper function to decrease reference count to module + * and device. Power off the device. + */ +static inline void coresight_put_ref(struct coresight_device *csdev) +{ + struct device *dev = csdev->dev.parent; + + pm_runtime_put(dev); + put_device(dev); + module_put(dev->driver->owner); +} + /* * coresight_grab_device - Power up this device and any of the helper * devices connected to it for trace operation. Since the helper devices * don't appear on the trace path, they should be handled along with the * the master device. */ -static void coresight_grab_device(struct coresight_device *csdev) +static int coresight_grab_device(struct coresight_device *csdev) { int i; @@ -649,9 +681,20 @@ static void coresight_grab_device(struct coresight_device *csdev) child = csdev->pdata->conns[i].child_dev; if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) - pm_runtime_get_sync(child->dev.parent); + if (!coresight_get_ref(child)) + goto err; + } + if (coresight_get_ref(csdev)) + return 0; +err: + for (i--; i >= 0; i--) { + struct coresight_device *child; + + child = csdev->pdata->conns[i].child_dev; + if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) + coresight_put_ref(child); } - pm_runtime_get_sync(csdev->dev.parent); + return -ENODEV; } /* @@ -662,13 +705,13 @@ static void coresight_drop_device(struct coresight_device *csdev) { int i; - pm_runtime_put(csdev->dev.parent); + coresight_put_ref(csdev); for (i = 0; i < csdev->pdata->nr_outport; i++) { struct coresight_device *child; child = csdev->pdata->conns[i].child_dev; if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) - pm_runtime_put(child->dev.parent); + coresight_put_ref(child); } } @@ -687,7 +730,7 @@ static int _coresight_build_path(struct coresight_device *csdev, struct coresight_device *sink, struct list_head *path) { - int i; + int i, ret; bool found = false; struct coresight_node *node; @@ -721,7 +764,11 @@ static int _coresight_build_path(struct coresight_device *csdev, if (!node) return -ENOMEM; - coresight_grab_device(csdev); + ret = coresight_grab_device(csdev); + if (ret) { + kfree(node); + return ret; + } node->csdev = csdev; list_add(&node->link, path);