From: Christoph Hellwig <hch@lst.de>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jason Gunthorpe <jgg@nvidia.com>,
Alex Williamson <alex.williamson@redhat.com>,
Kirti Wankhede <kwankhede@nvidia.com>
Cc: David Airlie <airlied@linux.ie>,
Tony Krowiak <akrowiak@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Cornelia Huck <cohuck@redhat.com>,
Jonathan Corbet <corbet@lwn.net>, Daniel Vetter <daniel@ffwll.ch>,
dri-devel@lists.freedesktop.org,
Vasily Gorbik <gor@linux.ibm.com>,
Heiko Carstens <hca@linux.ibm.com>,
intel-gfx@lists.freedesktop.org,
Jani Nikula <jani.nikula@linux.intel.com>,
Jason Herne <jjherne@linux.ibm.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
kvm@vger.kernel.org, linux-doc@vger.kernel.org,
linux-s390@vger.kernel.org, Halil Pasic <pasic@linux.ibm.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Rodrigo Vivi <rodrigo.vivi@intel.com>
Subject: [PATCH 03/10] driver core: Flow the return code from ->probe() through to sysfs bind
Date: Tue, 15 Jun 2021 15:35:12 +0200 [thread overview]
Message-ID: <20210615133519.754763-4-hch@lst.de> (raw)
In-Reply-To: <20210615133519.754763-1-hch@lst.de>
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>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
---
drivers/base/bus.c | 6 +-----
drivers/base/dd.c | 29 ++++++++++++++++++++---------
2 files changed, 21 insertions(+), 14 deletions(-)
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 fd83817240e6..25341f52198c 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -607,10 +607,10 @@ 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;
}
@@ -653,7 +653,6 @@ 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;
@@ -746,8 +745,8 @@ 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.
@@ -882,7 +881,14 @@ 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)
@@ -1038,7 +1044,7 @@ 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)
{
@@ -1048,6 +1054,9 @@ 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;
}
@@ -1114,7 +1123,9 @@ 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;
}
--
2.30.2
next prev parent reply other threads:[~2021-06-15 13:39 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-15 13:35 Allow mdev drivers to directly create the vfio_device (v3) Christoph Hellwig
2021-06-15 13:35 ` [PATCH 01/10] driver core: Pull required checks into driver_probe_device() Christoph Hellwig
2021-06-15 13:35 ` [PATCH 02/10] driver core: Better distinguish probe errors in really_probe Christoph Hellwig
2021-06-15 13:53 ` Cornelia Huck
2021-06-15 14:09 ` Greg Kroah-Hartman
2021-06-15 14:09 ` Greg Kroah-Hartman
2021-06-16 20:20 ` Kirti Wankhede
2021-06-15 13:35 ` Christoph Hellwig [this message]
2021-06-15 13:35 ` [PATCH 04/10] driver core: Don't return EPROBE_DEFER to userspace during sysfs bind Christoph Hellwig
2021-06-15 14:03 ` Cornelia Huck
2021-06-15 19:36 ` Alex Williamson
2021-06-15 13:35 ` [PATCH 05/10] driver core: Export device_driver_attach() Christoph Hellwig
2021-06-15 14:10 ` Greg Kroah-Hartman
2021-06-15 13:35 ` [PATCH 06/10] vfio/mdev: Remove CONFIG_VFIO_MDEV_DEVICE Christoph Hellwig
2021-06-15 14:10 ` Greg Kroah-Hartman
2021-06-16 20:20 ` Kirti Wankhede
2021-06-15 13:35 ` [PATCH 07/10] vfio/mdev: Allow the mdev_parent_ops to specify the device driver to bind Christoph Hellwig
2021-06-15 14:06 ` Cornelia Huck
2021-06-15 14:11 ` Greg Kroah-Hartman
2021-06-16 0:00 ` Jason Gunthorpe
2021-06-16 6:39 ` Greg Kroah-Hartman
2021-06-16 20:20 ` Kirti Wankhede
2021-06-15 13:35 ` [PATCH 08/10] vfio/mtty: Convert to use vfio_register_group_dev() Christoph Hellwig
2021-06-15 14:11 ` Greg Kroah-Hartman
2021-06-16 20:20 ` Kirti Wankhede
2021-06-15 13:35 ` [PATCH 09/10] vfio/mdpy: " Christoph Hellwig
2021-06-15 14:12 ` Greg Kroah-Hartman
2021-06-15 13:35 ` [PATCH 10/10] vfio/mbochs: " Christoph Hellwig
2021-06-15 14:12 ` Greg Kroah-Hartman
2021-06-15 19:35 ` Allow mdev drivers to directly create the vfio_device (v3) Alex Williamson
2021-06-15 20:35 ` Jason Gunthorpe
2021-06-16 3:13 ` Christoph Hellwig
2021-06-16 14:03 ` Jason Gunthorpe
-- strict thread matches above, loose matches on Subject: below --
2021-06-17 14:22 Allow mdev drivers to directly create the vfio_device (v4) Christoph Hellwig
2021-06-17 14:22 ` [PATCH 03/10] driver core: Flow the return code from ->probe() through to sysfs bind Christoph Hellwig
2021-06-14 15:08 Allow mdev drivers to directly create the vfio_device (v2 / alternative) Christoph Hellwig
2021-06-14 15:08 ` [PATCH 03/10] driver core: Flow the return code from ->probe() through to sysfs bind Christoph Hellwig
2021-06-15 5:18 ` Greg Kroah-Hartman
2021-06-15 10:31 ` Cornelia Huck
2021-06-08 0:55 [PATCH 00/10] Allow mdev drivers to directly create the vfio_device Jason Gunthorpe
2021-06-08 0:55 ` [PATCH 03/10] driver core: Flow the return code from ->probe() through to sysfs bind Jason Gunthorpe
2021-06-08 6:07 ` Christoph Hellwig
2021-06-08 23:53 ` Jason Gunthorpe
2021-06-08 6:47 ` Greg Kroah-Hartman
2021-06-08 12:30 ` Jason Gunthorpe
2021-06-08 13:16 ` Greg Kroah-Hartman
2021-06-08 14:03 ` Jason Gunthorpe
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