Messages in this thread Patch in this message | | | Subject | [PATCH] driver core: driver_bind attribute returns incorrect value | From | Ryan <> | Date | Wed, 22 Mar 2006 16:26:25 -0500 |
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The manual driver <-> device binding attribute in sysfs doesn't return the correct value on failure or success of driver_probe_device. driver_probe_device returns 1 on success (the driver accepted the device) or 0 on probe failure (when the driver didn't accept the device but no real error occured). However, the attribute can't just return 0 or 1, it must return the number of bytes consumed from buf or an error value. Returning 0 indicates to userspace that nothing was written (even though the kernel has tried to do the bind/probe and failed). Returning 1 indicates that only one character was accepted in which case userspace will re-try the write with a partial string.
A more correct version of driver_bind would return count (to indicate the entire string was consumed) when driver_probe_device returns 1 and -ENODEV when driver_probe_device returns 0. This patch makes that change.
Signed-off-by: Ryan Wilson <hap9@epoch.ncsc.mil>
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drivers/base/bus.c | 5 +++++ 1 files changed, 5 insertions(+)
--- linux-2.6.16-rc5/drivers/base/bus.c 2006-03-16 10:50:20.000000000 -0500 +++ linux-2.6.16-rc5/drivers/base/bus.c 2006-03-16 11:02:08.000000000 -0500 @@ -188,6 +188,11 @@ static ssize_t driver_bind(struct device up(&dev->sem); if (dev->parent) up(&dev->parent->sem); + + if (err > 0) /* success */ + err = count; + else if (err == 0) /* driver didn't accept device */ + err = -ENODEV; } put_device(dev); put_bus(bus);
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