| Message ID | 20210614150846.4111871-4-hch@lst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [01/10] driver core: Pull required checks into driver_probe_device() | expand |
On Mon, Jun 14, 2021 at 05:08:39PM +0200, Christoph Hellwig wrote: > Currently really_probe() returns 1 on success and 0 if the probe() call > fails. This return code arrangement is designed to be useful for > __device_attach_driver() which is walking the device list and trying every > driver. 0 means to keep trying. > > However, it is not useful for the other places that call through to > really_probe() that do actually want to see the probe() return code. > > For instance bind_store() would be better to return the actual error code > from the driver's probe method, not discarding it and returning -ENODEV. > > Reorganize things so that really_probe() returns the error code from > ->probe as a (inverted) positive number, and 0 for successful attach. > > With this, __device_attach_driver can ignore the (positive) probe errors, > return 1 to exit the loop for a successful binding and pass on the > other negative errors, while device_driver_attach simplify inverts the > positive errors and returns all errors to the sysfs code. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > drivers/base/bus.c | 6 +----- > drivers/base/dd.c | 29 ++++++++++++++++++++--------- > 2 files changed, 21 insertions(+), 14 deletions(-) Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On Mon, Jun 14 2021, Christoph Hellwig <hch@lst.de> wrote: > Currently really_probe() returns 1 on success and 0 if the probe() call > fails. This return code arrangement is designed to be useful for > __device_attach_driver() which is walking the device list and trying every > driver. 0 means to keep trying. > > However, it is not useful for the other places that call through to > really_probe() that do actually want to see the probe() return code. > > For instance bind_store() would be better to return the actual error code > from the driver's probe method, not discarding it and returning -ENODEV. > > Reorganize things so that really_probe() returns the error code from > ->probe as a (inverted) positive number, and 0 for successful attach. > > With this, __device_attach_driver can ignore the (positive) probe errors, > return 1 to exit the loop for a successful binding and pass on the > other negative errors, while device_driver_attach simplify inverts the > positive errors and returns all errors to the sysfs code. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > drivers/base/bus.c | 6 +----- > drivers/base/dd.c | 29 ++++++++++++++++++++--------- > 2 files changed, 21 insertions(+), 14 deletions(-) Reviewed-by: Cornelia Huck <cohuck@redhat.com>
diff --git a/drivers/base/bus.c b/drivers/base/bus.c index 7de13302e8c8..1f6b4bd61056 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -212,13 +212,9 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf, dev = bus_find_device_by_name(bus, NULL, buf); if (dev && driver_match_device(drv, dev)) { err = device_driver_attach(drv, dev); - - if (err > 0) { + if (!err) { /* success */ err = count; - } else if (err == 0) { - /* driver didn't accept device */ - err = -ENODEV; } } put_device(dev); diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 999bc737a8f0..4c6af8c062c8 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -605,10 +605,10 @@ static int really_probe(struct device *dev, struct device_driver *drv) probe_ret = call_driver_probe(dev, drv); if (probe_ret) { /* - * Ignore errors returned by ->probe so that the next driver can - * try its luck. + * Return probe errors as positive values so that the callers + * can distinguish them from other errors. */ - ret = 0; + ret = -probe_ret; goto probe_failed; } @@ -651,7 +651,6 @@ static int really_probe(struct device *dev, struct device_driver *drv) dev->pm_domain->sync(dev); driver_bound(dev); - ret = 1; pr_debug("bus: '%s': %s: bound device %s to driver %s\n", drv->bus->name, __func__, dev_name(dev), drv->name); goto done; @@ -744,8 +743,8 @@ EXPORT_SYMBOL_GPL(wait_for_device_probe); * @dev: device to try to bind to the driver * * This function returns -ENODEV if the device is not registered, -EBUSY if it - * already has a driver, and 1 if the device is bound successfully and 0 - * otherwise. + * already has a driver, 0 if the device is bound successfully and a positive + * (inverted) error code for failures from the ->probe method. * * This function must be called with @dev lock held. When called for a * USB interface, @dev->parent lock must be held as well. @@ -880,7 +879,14 @@ static int __device_attach_driver(struct device_driver *drv, void *_data) if (data->check_async && async_allowed != data->want_async) return 0; - return driver_probe_device(drv, dev); + /* + * Ignore errors returned by ->probe so that the next driver can try + * its luck. + */ + ret = driver_probe_device(drv, dev); + if (ret < 0) + return ret; + return ret == 0; } static void __device_attach_async_helper(void *_dev, async_cookie_t cookie) @@ -1036,7 +1042,7 @@ static void __device_driver_unlock(struct device *dev, struct device *parent) * @dev: Device to attach it to * * Manually attach driver to a device. Will acquire both @dev lock and - * @dev->parent lock if needed. + * @dev->parent lock if needed. Returns 0 on success, -ERR on failure. */ int device_driver_attach(struct device_driver *drv, struct device *dev) { @@ -1046,6 +1052,9 @@ int device_driver_attach(struct device_driver *drv, struct device *dev) ret = driver_probe_device(drv, dev); __device_driver_unlock(dev, dev->parent); + /* also return probe errors as normal negative errnos */ + if (ret > 0) + ret = -ret; return ret; } @@ -1112,7 +1121,9 @@ static int __driver_attach(struct device *dev, void *data) return 0; } - device_driver_attach(drv, dev); + __device_driver_lock(dev, dev->parent); + driver_probe_device(drv, dev); + __device_driver_unlock(dev, dev->parent); return 0; }
Currently really_probe() returns 1 on success and 0 if the probe() call fails. This return code arrangement is designed to be useful for __device_attach_driver() which is walking the device list and trying every driver. 0 means to keep trying. However, it is not useful for the other places that call through to really_probe() that do actually want to see the probe() return code. For instance bind_store() would be better to return the actual error code from the driver's probe method, not discarding it and returning -ENODEV. Reorganize things so that really_probe() returns the error code from ->probe as a (inverted) positive number, and 0 for successful attach. With this, __device_attach_driver can ignore the (positive) probe errors, return 1 to exit the loop for a successful binding and pass on the other negative errors, while device_driver_attach simplify inverts the positive errors and returns all errors to the sysfs code. Signed-off-by: Christoph Hellwig <hch@lst.de> --- drivers/base/bus.c | 6 +----- drivers/base/dd.c | 29 ++++++++++++++++++++--------- 2 files changed, 21 insertions(+), 14 deletions(-)