diff options
author | Jason Gunthorpe <jgg@nvidia.com> | 2021-06-17 16:22:09 +0200 |
---|---|---|
committer | Alex Williamson <alex.williamson@redhat.com> | 2021-06-21 15:29:24 -0600 |
commit | 204db60c83574559a8e08ce4bbd0029d56b8ab2e (patch) | |
tree | 3741c49db2424f57bb217eee62405067b361a9b7 | |
parent | 009c9aa5be652675a06d5211e1640e02bbb1c33d (diff) | |
download | linux-204db60c83574559a8e08ce4bbd0029d56b8ab2e.tar.bz2 |
driver core: Pull required checks into driver_probe_device()
Checking if the dev is dead or if the dev is already bound is a required
precondition to invoking driver_probe_device(). All the call chains
leading here duplicate these checks.
Add it directly to driver_probe_device() so the precondition is clear and
remove the checks from device_driver_attach() and
__driver_attach_async_helper().
The other call chain going through __device_attach_driver() does have
these same checks but they are inlined into logic higher up the call stack
and can't be removed.
The sysfs uAPI call chain starting at bind_store() is a bit confused
because it reads dev->driver unlocked and returns -ENODEV if it is !NULL,
otherwise it reads it again under lock and returns 0 if it is !NULL. Fix
this to always return -EBUSY and always read dev->driver under its lock.
Done in preparation for the next patches which will add additional
callers to driver_probe_device() and will need these checks as well.
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
[hch: drop the extra checks in device_driver_attach and bind_store]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Link: https://lore.kernel.org/r/20210617142218.1877096-2-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
-rw-r--r-- | drivers/base/bus.c | 2 | ||||
-rw-r--r-- | drivers/base/dd.c | 32 |
2 files changed, 11 insertions, 23 deletions
diff --git a/drivers/base/bus.c b/drivers/base/bus.c index 36d0c654ea61..7de13302e8c8 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -210,7 +210,7 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf, int err = -ENODEV; dev = bus_find_device_by_name(bus, NULL, buf); - if (dev && dev->driver == NULL && driver_match_device(drv, dev)) { + if (dev && driver_match_device(drv, dev)) { err = device_driver_attach(drv, dev); if (err > 0) { diff --git a/drivers/base/dd.c b/drivers/base/dd.c index ecd7cf848daf..7477d3322b3a 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -733,8 +733,9 @@ EXPORT_SYMBOL_GPL(wait_for_device_probe); * @drv: driver to bind a device to * @dev: device to try to bind to the driver * - * This function returns -ENODEV if the device is not registered, - * 1 if the device is bound successfully and 0 otherwise. + * 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. * * This function must be called with @dev lock held. When called for a * USB interface, @dev->parent lock must be held as well. @@ -745,8 +746,10 @@ static int driver_probe_device(struct device_driver *drv, struct device *dev) { int ret = 0; - if (!device_is_registered(dev)) + if (dev->p->dead || !device_is_registered(dev)) return -ENODEV; + if (dev->driver) + return -EBUSY; dev->can_match = true; pr_debug("bus: '%s': %s: matched device %s with driver %s\n", @@ -1027,17 +1030,10 @@ static void __device_driver_unlock(struct device *dev, struct device *parent) */ int device_driver_attach(struct device_driver *drv, struct device *dev) { - int ret = 0; + int ret; __device_driver_lock(dev, dev->parent); - - /* - * If device has been removed or someone has already successfully - * bound a driver before us just skip the driver probe call. - */ - if (!dev->p->dead && !dev->driver) - ret = driver_probe_device(drv, dev); - + ret = driver_probe_device(drv, dev); __device_driver_unlock(dev, dev->parent); return ret; @@ -1047,19 +1043,11 @@ static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie) { struct device *dev = _dev; struct device_driver *drv; - int ret = 0; + int ret; __device_driver_lock(dev, dev->parent); - drv = dev->p->async_driver; - - /* - * If device has been removed or someone has already successfully - * bound a driver before us just skip the driver probe call. - */ - if (!dev->p->dead && !dev->driver) - ret = driver_probe_device(drv, dev); - + ret = driver_probe_device(drv, dev); __device_driver_unlock(dev, dev->parent); dev_dbg(dev, "driver %s async attach completed: %d\n", drv->name, ret); |