Re: [PATCH] driver core: Avoid pointless deferred probe attempts
On Thu, Feb 18, 2021 at 9:24 AM Saravana Kannan wrote: > > On Thu, Feb 18, 2021 at 9:18 AM Rafael J. Wysocki wrote: > > > > On Thu, Feb 18, 2021 at 12:51 AM Saravana Kannan > > wrote: > > > > > > There's no point in adding a device to the deferred probe list if we > > > know for sure that it doesn't have a matching driver. So, check if a > > > device can match with a driver before adding it to the deferred probe > > > list. > > > > What if a matching driver module loads in the meantime? > > Driver registration always triggers a match attempt and this flag will > get set at that point. Yes, the user can disable autoprobe, but > that'll block deferred probes too. > Let me know what you think Rafael. -Saravana > > > > > > > > > Signed-off-by: Saravana Kannan > > > --- > > > Geert, > > > > > > Can you give this a shot for your I2C DMA issue with fw_devlink=on? > > > > > > -Saravana > > > > > > drivers/base/dd.c | 6 ++ > > > include/linux/device.h | 4 > > > 2 files changed, 10 insertions(+) > > > > > > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > > > index 9179825ff646..f18963f42e21 100644 > > > --- a/drivers/base/dd.c > > > +++ b/drivers/base/dd.c > > > @@ -123,6 +123,9 @@ static DECLARE_WORK(deferred_probe_work, > > > deferred_probe_work_func); > > > > > > void driver_deferred_probe_add(struct device *dev) > > > { > > > + if (!dev->can_match) > > > + return; > > > + > > > mutex_lock(&deferred_probe_mutex); > > > if (list_empty(&dev->p->deferred_probe)) { > > > dev_dbg(dev, "Added to deferred list\n"); > > > @@ -726,6 +729,7 @@ static int driver_probe_device(struct device_driver > > > *drv, struct device *dev) > > > if (!device_is_registered(dev)) > > > return -ENODEV; > > > > > > + dev->can_match = true; > > > pr_debug("bus: '%s': %s: matched device %s with driver %s\n", > > > drv->bus->name, __func__, dev_name(dev), drv->name); > > > > > > @@ -829,6 +833,7 @@ static int __device_attach_driver(struct > > > device_driver *drv, void *_data) > > > return 0; > > > } else if (ret == -EPROBE_DEFER) { > > > dev_dbg(dev, "Device match requests probe deferral\n"); > > > + dev->can_match = true; > > > driver_deferred_probe_add(dev); > > > } else if (ret < 0) { > > > dev_dbg(dev, "Bus failed to match device: %d\n", ret); > > > @@ -1064,6 +1069,7 @@ static int __driver_attach(struct device *dev, void > > > *data) > > > return 0; > > > } else if (ret == -EPROBE_DEFER) { > > > dev_dbg(dev, "Device match requests probe deferral\n"); > > > + dev->can_match = true; > > > driver_deferred_probe_add(dev); > > > } else if (ret < 0) { > > > dev_dbg(dev, "Bus failed to match device: %d\n", ret); > > > diff --git a/include/linux/device.h b/include/linux/device.h > > > index 7619a84f8ce4..1f9cc1ba78bc 100644 > > > --- a/include/linux/device.h > > > +++ b/include/linux/device.h > > > @@ -438,6 +438,9 @@ struct dev_links_info { > > > * @state_synced: The hardware state of this device has been synced to > > > match > > > * the software state of this device by calling the > > > driver/bus > > > * sync_state() callback. > > > + * @can_match: The device has matched with a driver at least once or it > > > is in > > > + * a bus (like AMBA) which can't check for matching drivers > > > until > > > + * other devices probe successfully. > > > * @dma_coherent: this particular device is dma coherent, even if the > > > * architecture supports non-coherent devices. > > > * @dma_ops_bypass: If set to %true then the dma_ops are bypassed for the > > > @@ -544,6 +547,7 @@ struct device { > > > booloffline:1; > > > boolof_node_reused:1; > > > boolstate_synced:1; > > > + boolcan_match:1; > > > #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \ > > > defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \ > > > defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) > > > --
Re: [PATCH] driver core: Avoid pointless deferred probe attempts
On Tue, Feb 23, 2021 at 2:10 AM Geert Uytterhoeven wrote: > > Hi Saravana, > > On Thu, Feb 18, 2021 at 12:51 AM Saravana Kannan wrote: > > There's no point in adding a device to the deferred probe list if we > > know for sure that it doesn't have a matching driver. So, check if a > > device can match with a driver before adding it to the deferred probe > > list. > > > > Signed-off-by: Saravana Kannan > > Thanks for your patch! > > > --- > > Geert, > > > > Can you give this a shot for your I2C DMA issue with fw_devlink=on? > > Yes, this makes I2C use DMA again on Salvator-XS during kernel boot-up. Thanks for testing Geert! > I haven't run any more elaborate tests on other platforms. Yeah, this change should only go into 5.13 after it gets tested as part of driver-core-next. -Saravana
Re: [PATCH] driver core: Avoid pointless deferred probe attempts
Hi Saravana, On Thu, Feb 18, 2021 at 12:51 AM Saravana Kannan wrote: > There's no point in adding a device to the deferred probe list if we > know for sure that it doesn't have a matching driver. So, check if a > device can match with a driver before adding it to the deferred probe > list. > > Signed-off-by: Saravana Kannan Thanks for your patch! > --- > Geert, > > Can you give this a shot for your I2C DMA issue with fw_devlink=on? Yes, this makes I2C use DMA again on Salvator-XS during kernel boot-up. I haven't run any more elaborate tests on other platforms. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
Re: [PATCH] driver core: Avoid pointless deferred probe attempts
On Thu, Feb 18, 2021 at 9:24 AM Saravana Kannan wrote: > > On Thu, Feb 18, 2021 at 9:18 AM Rafael J. Wysocki wrote: > > > > On Thu, Feb 18, 2021 at 12:51 AM Saravana Kannan > > wrote: > > > > > > There's no point in adding a device to the deferred probe list if we > > > know for sure that it doesn't have a matching driver. So, check if a > > > device can match with a driver before adding it to the deferred probe > > > list. > > > > What if a matching driver module loads in the meantime? > > Driver registration always triggers a match attempt and this flag will > get set at that point. Yes, the user can disable autoprobe, but > that'll block deferred probes too. > Btw, this can wait for 5.13. Doesn't need to go into 5.12-rcX. > > > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > > > index 9179825ff646..f18963f42e21 100644 > > > --- a/drivers/base/dd.c > > > +++ b/drivers/base/dd.c > > > @@ -123,6 +123,9 @@ static DECLARE_WORK(deferred_probe_work, > > > deferred_probe_work_func); > > > > > > void driver_deferred_probe_add(struct device *dev) > > > { > > > + if (!dev->can_match) > > > + return; > > > + Also, if you are worried about this check, for now, I can move it inside device_links_driver_bound() which is the only place that currently adds a device to the deferred probe list before the driver is present. But it seemed like a good check in general to have in driver_deferred_probe_add(), so I put it there. -Saravana
Re: [PATCH] driver core: Avoid pointless deferred probe attempts
On Thu, Feb 18, 2021 at 9:18 AM Rafael J. Wysocki wrote: > > On Thu, Feb 18, 2021 at 12:51 AM Saravana Kannan wrote: > > > > There's no point in adding a device to the deferred probe list if we > > know for sure that it doesn't have a matching driver. So, check if a > > device can match with a driver before adding it to the deferred probe > > list. > > What if a matching driver module loads in the meantime? Driver registration always triggers a match attempt and this flag will get set at that point. Yes, the user can disable autoprobe, but that'll block deferred probes too. -Saravana > > > > > Signed-off-by: Saravana Kannan > > --- > > Geert, > > > > Can you give this a shot for your I2C DMA issue with fw_devlink=on? > > > > -Saravana > > > > drivers/base/dd.c | 6 ++ > > include/linux/device.h | 4 > > 2 files changed, 10 insertions(+) > > > > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > > index 9179825ff646..f18963f42e21 100644 > > --- a/drivers/base/dd.c > > +++ b/drivers/base/dd.c > > @@ -123,6 +123,9 @@ static DECLARE_WORK(deferred_probe_work, > > deferred_probe_work_func); > > > > void driver_deferred_probe_add(struct device *dev) > > { > > + if (!dev->can_match) > > + return; > > + > > mutex_lock(&deferred_probe_mutex); > > if (list_empty(&dev->p->deferred_probe)) { > > dev_dbg(dev, "Added to deferred list\n"); > > @@ -726,6 +729,7 @@ static int driver_probe_device(struct device_driver > > *drv, struct device *dev) > > if (!device_is_registered(dev)) > > return -ENODEV; > > > > + dev->can_match = true; > > pr_debug("bus: '%s': %s: matched device %s with driver %s\n", > > drv->bus->name, __func__, dev_name(dev), drv->name); > > > > @@ -829,6 +833,7 @@ static int __device_attach_driver(struct device_driver > > *drv, void *_data) > > return 0; > > } else if (ret == -EPROBE_DEFER) { > > dev_dbg(dev, "Device match requests probe deferral\n"); > > + dev->can_match = true; > > driver_deferred_probe_add(dev); > > } else if (ret < 0) { > > dev_dbg(dev, "Bus failed to match device: %d\n", ret); > > @@ -1064,6 +1069,7 @@ static int __driver_attach(struct device *dev, void > > *data) > > return 0; > > } else if (ret == -EPROBE_DEFER) { > > dev_dbg(dev, "Device match requests probe deferral\n"); > > + dev->can_match = true; > > driver_deferred_probe_add(dev); > > } else if (ret < 0) { > > dev_dbg(dev, "Bus failed to match device: %d\n", ret); > > diff --git a/include/linux/device.h b/include/linux/device.h > > index 7619a84f8ce4..1f9cc1ba78bc 100644 > > --- a/include/linux/device.h > > +++ b/include/linux/device.h > > @@ -438,6 +438,9 @@ struct dev_links_info { > > * @state_synced: The hardware state of this device has been synced to > > match > > * the software state of this device by calling the > > driver/bus > > * sync_state() callback. > > + * @can_match: The device has matched with a driver at least once or it is > > in > > + * a bus (like AMBA) which can't check for matching drivers > > until > > + * other devices probe successfully. > > * @dma_coherent: this particular device is dma coherent, even if the > > * architecture supports non-coherent devices. > > * @dma_ops_bypass: If set to %true then the dma_ops are bypassed for the > > @@ -544,6 +547,7 @@ struct device { > > booloffline:1; > > boolof_node_reused:1; > > boolstate_synced:1; > > + boolcan_match:1; > > #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \ > > defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \ > > defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) > > --
Re: [PATCH] driver core: Avoid pointless deferred probe attempts
On Thu, Feb 18, 2021 at 12:51 AM Saravana Kannan wrote: > > There's no point in adding a device to the deferred probe list if we > know for sure that it doesn't have a matching driver. So, check if a > device can match with a driver before adding it to the deferred probe > list. What if a matching driver module loads in the meantime? > > Signed-off-by: Saravana Kannan > --- > Geert, > > Can you give this a shot for your I2C DMA issue with fw_devlink=on? > > -Saravana > > drivers/base/dd.c | 6 ++ > include/linux/device.h | 4 > 2 files changed, 10 insertions(+) > > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > index 9179825ff646..f18963f42e21 100644 > --- a/drivers/base/dd.c > +++ b/drivers/base/dd.c > @@ -123,6 +123,9 @@ static DECLARE_WORK(deferred_probe_work, > deferred_probe_work_func); > > void driver_deferred_probe_add(struct device *dev) > { > + if (!dev->can_match) > + return; > + > mutex_lock(&deferred_probe_mutex); > if (list_empty(&dev->p->deferred_probe)) { > dev_dbg(dev, "Added to deferred list\n"); > @@ -726,6 +729,7 @@ static int driver_probe_device(struct device_driver *drv, > struct device *dev) > if (!device_is_registered(dev)) > return -ENODEV; > > + dev->can_match = true; > pr_debug("bus: '%s': %s: matched device %s with driver %s\n", > drv->bus->name, __func__, dev_name(dev), drv->name); > > @@ -829,6 +833,7 @@ static int __device_attach_driver(struct device_driver > *drv, void *_data) > return 0; > } else if (ret == -EPROBE_DEFER) { > dev_dbg(dev, "Device match requests probe deferral\n"); > + dev->can_match = true; > driver_deferred_probe_add(dev); > } else if (ret < 0) { > dev_dbg(dev, "Bus failed to match device: %d\n", ret); > @@ -1064,6 +1069,7 @@ static int __driver_attach(struct device *dev, void > *data) > return 0; > } else if (ret == -EPROBE_DEFER) { > dev_dbg(dev, "Device match requests probe deferral\n"); > + dev->can_match = true; > driver_deferred_probe_add(dev); > } else if (ret < 0) { > dev_dbg(dev, "Bus failed to match device: %d\n", ret); > diff --git a/include/linux/device.h b/include/linux/device.h > index 7619a84f8ce4..1f9cc1ba78bc 100644 > --- a/include/linux/device.h > +++ b/include/linux/device.h > @@ -438,6 +438,9 @@ struct dev_links_info { > * @state_synced: The hardware state of this device has been synced to match > * the software state of this device by calling the driver/bus > * sync_state() callback. > + * @can_match: The device has matched with a driver at least once or it is in > + * a bus (like AMBA) which can't check for matching drivers until > + * other devices probe successfully. > * @dma_coherent: this particular device is dma coherent, even if the > * architecture supports non-coherent devices. > * @dma_ops_bypass: If set to %true then the dma_ops are bypassed for the > @@ -544,6 +547,7 @@ struct device { > booloffline:1; > boolof_node_reused:1; > boolstate_synced:1; > + boolcan_match:1; > #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \ > defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \ > defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) > --
[PATCH] driver core: Avoid pointless deferred probe attempts
There's no point in adding a device to the deferred probe list if we know for sure that it doesn't have a matching driver. So, check if a device can match with a driver before adding it to the deferred probe list. Signed-off-by: Saravana Kannan --- Geert, Can you give this a shot for your I2C DMA issue with fw_devlink=on? -Saravana drivers/base/dd.c | 6 ++ include/linux/device.h | 4 2 files changed, 10 insertions(+) diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 9179825ff646..f18963f42e21 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -123,6 +123,9 @@ static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func); void driver_deferred_probe_add(struct device *dev) { + if (!dev->can_match) + return; + mutex_lock(&deferred_probe_mutex); if (list_empty(&dev->p->deferred_probe)) { dev_dbg(dev, "Added to deferred list\n"); @@ -726,6 +729,7 @@ static int driver_probe_device(struct device_driver *drv, struct device *dev) if (!device_is_registered(dev)) return -ENODEV; + dev->can_match = true; pr_debug("bus: '%s': %s: matched device %s with driver %s\n", drv->bus->name, __func__, dev_name(dev), drv->name); @@ -829,6 +833,7 @@ static int __device_attach_driver(struct device_driver *drv, void *_data) return 0; } else if (ret == -EPROBE_DEFER) { dev_dbg(dev, "Device match requests probe deferral\n"); + dev->can_match = true; driver_deferred_probe_add(dev); } else if (ret < 0) { dev_dbg(dev, "Bus failed to match device: %d\n", ret); @@ -1064,6 +1069,7 @@ static int __driver_attach(struct device *dev, void *data) return 0; } else if (ret == -EPROBE_DEFER) { dev_dbg(dev, "Device match requests probe deferral\n"); + dev->can_match = true; driver_deferred_probe_add(dev); } else if (ret < 0) { dev_dbg(dev, "Bus failed to match device: %d\n", ret); diff --git a/include/linux/device.h b/include/linux/device.h index 7619a84f8ce4..1f9cc1ba78bc 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -438,6 +438,9 @@ struct dev_links_info { * @state_synced: The hardware state of this device has been synced to match * the software state of this device by calling the driver/bus * sync_state() callback. + * @can_match: The device has matched with a driver at least once or it is in + * a bus (like AMBA) which can't check for matching drivers until + * other devices probe successfully. * @dma_coherent: this particular device is dma coherent, even if the * architecture supports non-coherent devices. * @dma_ops_bypass: If set to %true then the dma_ops are bypassed for the @@ -544,6 +547,7 @@ struct device { booloffline:1; boolof_node_reused:1; boolstate_synced:1; + boolcan_match:1; #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \ defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \ defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) -- 2.30.0.478.g8a0d178c01-goog