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Date: Fri, 12 Jul 2002 20:16:02 -0700 (PDT)
From: Patrick Mochel <mochel@osdl.org>
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To: Thunder from the hill <thunder@ngforever.de>
cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Compile warning in fs/partitions/check.c
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On Fri, 12 Jul 2002, Thunder from the hill wrote:

> Hi,
> 
> Compiling fs/partitions/check.c, I get a couple of warnings of "pointer to 
> integer of different size":
> 
> 
> kdev is a kdev_t here, driverfs_dev is a struct device.
> 
> 	kdev.value=(int)driverfs_dev->driver_data;
> 
> Is it okay to replace this with
> 
> 	kdev.value=(unsigned short)driverfs_dev->driver_data;
> 
> to make the warnings go away?

This code definitely shouldn't rely on the format of the kdev_t structure. 
It looks like it should be something like:

-	kdev.value=(int)driverfs_dev->driver_data;
-	return off ? 0 : sprintf (page, "%x\n",kdev.value);
+	kdev = val_to_kdev((int)driverfs_dev->driver_data);
+	return off ? 0 : sprintf (page, "%x\n",kdev_val(kdev));

> Also, struct driver_file_entry->show gets initialized here:
> 
> 	show: partition_device_kdev_read,
> 
> show being (ssize_t *)(struct device *driverfs_dev, char *page, size_t 
> 		       count, loff_t off);
> but expecting (ssize_t *)(void *, char *page, size_t count, loff_t off);

First off, you might want to specify that you are using a specific patch. 
The change of the first parameter of the show() and store() callbacks was 
in a patch I posted last week. As of a few seconds ago, it hadn't been 
merged into Linus' kernel.org tree. 

Second, the definition of the callbacks should change, and there should be
an appropriate cast in the function. I have patches for all the users of
those callbacks, but I'm waiting until I finally resolve the refcounting
issues and post and updated patch to post those. FWIW, the pointer passed
to those callbacks is guaranteed to be a struct device, so the warning is, 
for now, harmless. 

Finally, if you have driverfs questions/problems/concerns, please copy me 
(and not Richard). :)

	-pat

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