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Message-ID: <20080110142341.71af4dc5@gondolin.boeblingen.de.ibm.com>
Date: Thu, 10 Jan 2008 14:23:41 +0100
From: Cornelia Huck <cornelia.huck@...ibm.com>
To: Dave Young <hidave.darkstar@...il.com>
Cc: Greg KH <gregkh@...e.de>,
Stefan Richter <stefanr@...6.in-berlin.de>,
James.Bottomley@...senpartnership.com, linux-scsi@...r.kernel.org,
a.zummo@...ertech.it, peterz@...radead.org, cbou@...l.ru,
linux-kernel@...r.kernel.org, David Brownell <david-b@...bell.net>,
krh@...hat.com, stern@...land.harvard.edu,
rtc-linux@...glegroups.com,
spi-devel-general@...ts.sourceforge.net,
linux1394-devel@...ts.sourceforge.net, dwmw2@...radead.org,
davem@...emloft.net, jarkao2@...il.com
Subject: Re: [PATCH 0/7] convert semaphore to mutex in struct class
On Thu, 10 Jan 2008 17:48:43 +0800,
Dave Young <hidave.darkstar@...il.com> wrote:
Please add a kerneldoc comment for each of the new interfaces.
> +int class_for_each_device(struct class *class, void *data,
> + int (*fn)(struct device *, void *))
> +{
> + struct device *dev;
> + int error = 0;
> +
> + if (!class)
> + return -EINVAL;
> + mutex_lock(&class->mutex);
> + list_for_each_entry(dev, &class->devices, node) {
> + error = fn(dev, data);
Hm, the equivalent _for_each_device() functions all elevate the
device's refcount while calling fn(). I wonder whether we want this
here as well?
> + if (error)
> + break;
> + }
> + mutex_unlock(&class->mutex);
> +
> + return error;
> +}
> +EXPORT_SYMBOL_GPL(class_for_each_device);
> +
> +struct device *class_find_device(struct class *class, void *data,
> + int (*match)(struct device *, void *))
> +{
> + struct device *dev;
> +
> + if (!class)
> + return NULL;
> +
> + mutex_lock(&class->mutex);
> + list_for_each_entry(dev, &class->devices, node)
> + if (match(dev, data) && get_device(dev))
First get the reference and then drop it if the match function returns
0 to make this analogous to the other _find_device() functions?
> + break;
> + mutex_unlock(&class->mutex);
> +
> + return dev;
> +}
> +EXPORT_SYMBOL_GPL(class_find_device);
> +
> +int class_for_each_child(struct class *class, void *data,
> + int (*fn)(struct class_device *, void *))
Haven't looked at the callers, but isn't it better to convert them to
use struct device instead so we don't need to introduce new
class_device api?
> +{
> + struct class_device *dev;
> + int error = 0;
> +
> + if (!class)
> + return -EINVAL;
> + mutex_lock(&class->mutex);
> + list_for_each_entry(dev, &class->children, node) {
> + error = fn(dev, data);
Same comment as above concerning reference counts.
> + if (error)
> + break;
> + }
> + mutex_unlock(&class->mutex);
> +
> + return error;
> +}
> +EXPORT_SYMBOL_GPL(class_for_each_child);
> +
> +struct class_device *class_find_child(struct class *class, void *data,
> + int (*match)(struct class_device *, void *))
> +{
> + struct class_device *dev;
> +
> + if (!class)
> + return NULL;
> +
> + mutex_lock(&class->mutex);
> + list_for_each_entry(dev, &class->children, node)
> + if (match(dev, data) && class_device_get(dev))
And here.
> + break;
> + mutex_unlock(&class->mutex);
> +
> + return dev;
> +}
> +EXPORT_SYMBOL_GPL(class_find_child);
> +
--
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