[PATCH] fix dev_printk to work even in the absence of am attached driver

[PATCH] fix dev_printk to work even in the absence of am attached driver

[James Bottomley]

dev_printk makes an incredibly convenient hook to hang a logging
infrastructure.  For that reason, it would be very useful to make all
device driver logging go through it.

Unfortunately in SCSI we can't do this yet because we need to log
messages even when the device doesn't have a bound driver (either
because the user has chosen not to load it or because we're starting up
or shutting down).

The attached makes dev_printk work even in the absence of a bound driver
so we should now be able to use it at all points in the lifecycle of a
SCSI device.

James
Index: include/linux/device.h
===================================================================
RCS file: /var/cvs/linux-2.6/include/linux/device.h,v
retrieving revision 1.9
diff -u -r1.9 device.h
--- a/include/linux/device.h	15 Apr 2004 18:05:25 -0000	1.9
+++ b/include/linux/device.h	19 Apr 2004 20:36:57 -0000
@@ -400,7 +400,7 @@
 
 /* debugging and troubleshooting/diagnostic helpers. */
 #define dev_printk(level, dev, format, arg...)	\
-	printk(level "%s %s: " format , (dev)->driver->name , (dev)->bus_id , ## arg)
+	printk(level "%s %s: " format , (dev)->driver ? (dev)->driver->name : "(unbound)", (dev)->bus_id , ## arg)
 
 #ifdef DEBUG
 #define dev_dbg(dev, format, arg...)		\

Re: [PATCH] fix dev_printk to work even in the absence of am attached driver

[Greg KH]

On Mon, Apr 19, 2004 at 03:39:57PM -0500, James Bottomley wrote:
>  /* debugging and troubleshooting/diagnostic helpers. */
>  #define dev_printk(level, dev, format, arg...)	\
> -	printk(level "%s %s: " format , (dev)->driver->name , (dev)->bus_id , ## arg)
> +	printk(level "%s %s: " format , (dev)->driver ? (dev)->driver->name : "(unbound)", (dev)->bus_id , ## arg)

But doesn't this cause the string "(unbound)" to be created for every
dev_printk() call in the code?  I don't think gcc can optimize that very
well.  How about making a global string just for that, otherwise the
size police will come after me for adding such a patch :)

thanks,

greg k-h

Re: [PATCH] fix dev_printk to work even in the absence of am attached driver

[James Bottomley]

On Thu, 2004-04-22 at 17:07, Greg KH wrote: 
> But doesn't this cause the string "(unbound)" to be created for every
> dev_printk() call in the code?  I don't think gcc can optimize that very
> well.  How about making a global string just for that, otherwise the
> size police will come after me for adding such a patch :)

OK, I can't find an elegant way of making it global, so I think the best
thing to do is just leave it blank for no driver (gcc can optimise that
case). 

James 

===== include/linux/device.h 1.117 vs edited =====
--- 1.117/include/linux/device.h	Mon Apr 12 12:54:25 2004
+++ edited/include/linux/device.h	Tue May 11 08:58:44 2004
@@ -400,7 +400,7 @@
 
 /* debugging and troubleshooting/diagnostic helpers. */
 #define dev_printk(level, dev, format, arg...)	\
-	printk(level "%s %s: " format , (dev)->driver->name , (dev)->bus_id , ## arg)
+	printk(level "%s %s: " format , (dev)->driver ? (dev)->driver->name : "" , (dev)->bus_id , ## arg)
 
 #ifdef DEBUG
 #define dev_dbg(dev, format, arg...)		\

Re: [PATCH] fix dev_printk to work even in the absence of am attached driver

[Greg KH]

On Tue, May 11, 2004 at 09:00:47AM -0500, James Bottomley wrote:
> On Thu, 2004-04-22 at 17:07, Greg KH wrote: 
> > But doesn't this cause the string "(unbound)" to be created for every
> > dev_printk() call in the code?  I don't think gcc can optimize that very
> > well.  How about making a global string just for that, otherwise the
> > size police will come after me for adding such a patch :)
> 
> OK, I can't find an elegant way of making it global, so I think the best
> thing to do is just leave it blank for no driver (gcc can optimise that
> case). 

Ok, I can live with this, thanks.  Applied.

greg k-h