Re: Flaws with "UIO: Add the User IO core code" (with patch)

[Hans-Jürgen Koch <hjk@linutronix.de>]

Am Samstag 28 April 2007 22:24 schrieb Alan Cox:
> > > AFAIK we don't currently have any platform that runs binaries with
> > > different sizes of "int" but this is a) an unsigned value anyway, and b)
> > > should be a fixed type (eg u32)
> > 
> > I reviewed the code once more and find it OK. There is only one legal
> > value for the parameter "count" of uio_read(), and that's sizeof(int).
> 
> If you are a box with multiple supported binary types how big is an
> "int". We use explicit sizes to ensure that uio_read() will work when/if
> we get platforms which support binaries with differing ideas of the size
> of "int". Thus it should use s32 or s64 or similar.

Here's a fix to that effect:

Index: linux-2.6.22-rc/drivers/uio/uio.c
===================================================================
--- linux-2.6.22-rc.orig/drivers/uio/uio.c	2007-04-28 22:46:34.000000000 +0200
+++ linux-2.6.22-rc/drivers/uio/uio.c	2007-04-28 22:59:40.000000000 +0200
@@ -264,7 +264,7 @@
 
 struct uio_listener {
 	struct uio_device *dev;
-	int event_count;
+	s32 event_count;
 };
 
 static int uio_open(struct inode *inode, struct file *filep)
@@ -345,12 +345,12 @@
 	struct uio_device *idev = listener->dev;
 	DECLARE_WAITQUEUE(wait, current);
 	ssize_t retval;
-	int event_count;
+	s32 event_count;
 
 	if (idev->info->irq == UIO_IRQ_NONE)
 		return -EIO;
 
-	if (count != sizeof(int))
+	if (count != sizeof(s32))
 		return -EINVAL;
 
 	add_wait_queue(&idev->wait, &wait);


Thanks,
Hans
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