[RFC][expample patch] Make the kernel -Wshadow clean ?

[Jesper Juhl]

Hi,

Variables shadowing eachother have a nasty potential to contain hard to 
discover bugs, so I propose we clean that up.

There are *lots* of cases of variable shadowing in the kernel and real bugs 
could be lurking in there.

I'm full willing to audit every single case and clean them up, but before I 
begin such a task I want to "test the waters".

So to get things started I give you the patch below that cleans up

784 counts of
include/linux/jiffies.h:331: warning: declaration of 'jiffies' shadows a global declaration

784 counts of
include/linux/jiffies.h:369: warning: declaration of 'jiffies' shadows a global declaration

30 counts of
include/linux/usb.h:877: warning: declaration of 'complete' shadows a global declaration

30 counts of
include/linux/usb.h:908: warning: declaration of 'complete' shadows a global declaration

30 counts of
include/linux/usb.h:943: warning: declaration of 'complete' shadows a global declaration

1 count of
mm/swap.c:42: warning: declaration of 'page' shadows a parameter


So with just one simple patch we've nuked 1659 -Wshadow warnings out of a total
of 2403 that this build of mine generated with my regular .config
Of course I picked some of the easy targets to start with, a lot of the 
remaining ones are cases of 1-10 identical warnings generated by one instance.

Anyway, I think this is a worthwhile task and I'm willing to do it and we may 
even discover/fix real bugs along the way, so what do you say?

Comments are very welcome as always, and feel free to merge this patch as a 
starting point if you agree that this is something that ought to be done.


Signed-off-by: Jesper Juhl <jesper.juhl@xxxxxxxxx>
---

 include/linux/jiffies.h |    8 ++++----
 include/linux/usb.h     |   12 ++++++------
 mm/swap.c               |    2 +-
 3 files changed, 11 insertions(+), 11 deletions(-)

--- linux-2.6.15-rc5-git4-orig/include/linux/jiffies.h	2005-10-28 02:02:08.000000000 +0200
+++ linux-2.6.15-rc5-git4/include/linux/jiffies.h	2005-12-14 22:52:07.000000000 +0100
@@ -328,13 +328,13 @@ timespec_to_jiffies(const struct timespe
 }
 
 static __inline__ void
-jiffies_to_timespec(const unsigned long jiffies, struct timespec *value)
+jiffies_to_timespec(const unsigned long jiff, struct timespec *value)
 {
 	/*
 	 * Convert jiffies to nanoseconds and separate with
 	 * one divide.
 	 */
-	u64 nsec = (u64)jiffies * TICK_NSEC;
+	u64 nsec = (u64)jiff * TICK_NSEC;
 	value->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &value->tv_nsec);
 }
 
@@ -366,13 +366,13 @@ timeval_to_jiffies(const struct timeval 
 }
 
 static __inline__ void
-jiffies_to_timeval(const unsigned long jiffies, struct timeval *value)
+jiffies_to_timeval(const unsigned long jiff, struct timeval *value)
 {
 	/*
 	 * Convert jiffies to nanoseconds and separate with
 	 * one divide.
 	 */
-	u64 nsec = (u64)jiffies * TICK_NSEC;
+	u64 nsec = (u64)jiff * TICK_NSEC;
 	value->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &value->tv_usec);
 	value->tv_usec /= NSEC_PER_USEC;
 }
--- linux-2.6.15-rc5-git4-orig/include/linux/usb.h	2005-12-04 18:48:51.000000000 +0100
+++ linux-2.6.15-rc5-git4/include/linux/usb.h	2005-12-14 23:57:09.000000000 +0100
@@ -874,7 +874,7 @@ static inline void usb_fill_control_urb 
 					 unsigned char *setup_packet,
 					 void *transfer_buffer,
 					 int buffer_length,
-					 usb_complete_t complete,
+					 usb_complete_t comp,
 					 void *context)
 {
 	spin_lock_init(&urb->lock);
@@ -883,7 +883,7 @@ static inline void usb_fill_control_urb 
 	urb->setup_packet = setup_packet;
 	urb->transfer_buffer = transfer_buffer;
 	urb->transfer_buffer_length = buffer_length;
-	urb->complete = complete;
+	urb->complete = comp;
 	urb->context = context;
 }
 
@@ -905,7 +905,7 @@ static inline void usb_fill_bulk_urb (st
 				      unsigned int pipe,
 				      void *transfer_buffer,
 				      int buffer_length,
-				      usb_complete_t complete,
+				      usb_complete_t comp,
 				      void *context)
 {
 	spin_lock_init(&urb->lock);
@@ -913,7 +913,7 @@ static inline void usb_fill_bulk_urb (st
 	urb->pipe = pipe;
 	urb->transfer_buffer = transfer_buffer;
 	urb->transfer_buffer_length = buffer_length;
-	urb->complete = complete;
+	urb->complete = comp;
 	urb->context = context;
 }
 
@@ -940,7 +940,7 @@ static inline void usb_fill_int_urb (str
 				     unsigned int pipe,
 				     void *transfer_buffer,
 				     int buffer_length,
-				     usb_complete_t complete,
+				     usb_complete_t comp,
 				     void *context,
 				     int interval)
 {
@@ -949,7 +949,7 @@ static inline void usb_fill_int_urb (str
 	urb->pipe = pipe;
 	urb->transfer_buffer = transfer_buffer;
 	urb->transfer_buffer_length = buffer_length;
-	urb->complete = complete;
+	urb->complete = comp;
 	urb->context = context;
 	if (dev->speed == USB_SPEED_HIGH)
 		urb->interval = 1 << (interval - 1);
--- linux-2.6.15-rc5-git4-orig/mm/swap.c	2005-12-04 18:48:54.000000000 +0100
+++ linux-2.6.15-rc5-git4/mm/swap.c	2005-12-14 23:04:28.000000000 +0100
@@ -39,7 +39,7 @@ void put_page(struct page *page)
 	if (unlikely(PageCompound(page))) {
 		page = (struct page *)page_private(page);
 		if (put_page_testzero(page)) {
-			void (*dtor)(struct page *page);
+			void (*dtor)(struct page *pge);
 
 			dtor = (void (*)(struct page *))page[1].mapping;
 			(*dtor)(page);



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