linux-kernel - [PATCH] vsprintf: Remove SPECIAL from pointer types

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Date:	Sat, 05 Jul 2014 13:45:14 -0700
From:	Joe Perches <joe@...ches.com>
To:	"Maciej W. Rozycki" <macro@...ux-mips.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Grant Likely <grant.likely@...retlab.ca>,
	David Miller <davem@...emloft.net>, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] vsprintf: Remove SPECIAL from pointer types

Because gcc issues a complaint about any pointer format with %#p,
remove the use of SPECIAL to prefix 0x to various pointer types.

There are no uses in the kernel tree of %#p.

This removes the capability added by commit 725fe002d315
("vsprintf: correctly handle width when '#' flag used in %#p format").

There are some incidental message logging output changes of %pa
uses with this change.  None are in seq output so there are no
api changes.

Signed-off-by: Joe Perches <joe@...ches.com>
---

Fine by me, here...

On Sat, 2014-07-05 at 21:25 +0100, Maciej W. Rozycki wrote:
> On Sat, 5 Jul 2014, Joe Perches wrote:
> 
> > > > I don't think %#p is valid so it
> > > > shouldn't have been set by #.
> > > 
> > >  Huh?  As recently as last Wednesday you pointed me at the specific commit 
> > > from Grant that made it valid (GCC format complaints aside).
> > 
> > Those gcc complaints are precisely the thing
> > that makes it invalid.
> 
>  So enforce that in code then, clear the SPECIAL flag where appropriate 
> and do not try to handle it in one place while leaving other ones to 
> behave randomly (i.e. a supposedly fixed field width varies depending on 
> the two uppermost digits).  Please note that it's only your proposed 
> change that introduces that randomness, right now code does what's 
> supposed and documented to, except a bit inconsistently.
> 
> > I believe you're tilting at windmills.
> > 
> > Hey, it works sometimes.  Knock yourself out.
> 
>  I pointed out an inconsistency with the intent to propose a fix once a 
> consensus have been reached, one way or another.  And I think shifting the 
> inconsistency to a different place, which is what your proposal does, 
> isn't really a complete solution, although I do recognise the improvement.

 lib/vsprintf.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 6fe2c84..1cad65b 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -632,7 +632,7 @@ char *symbol_string(char *buf, char *end, void *ptr,
 	return string(buf, end, sym, spec);
 #else
 	spec.field_width = 2 * sizeof(void *);
-	spec.flags |= SPECIAL | SMALL | ZEROPAD;
+	spec.flags |= SMALL | ZEROPAD;
 	spec.base = 16;
 
 	return number(buf, end, value, spec);
@@ -1165,18 +1165,18 @@ char *address_val(char *buf, char *end, const void *addr,
 {
 	unsigned long long num;
 
-	spec.flags |= SPECIAL | SMALL | ZEROPAD;
+	spec.flags |= SMALL | ZEROPAD;
 	spec.base = 16;
 
 	switch (fmt[1]) {
 	case 'd':
 		num = *(const dma_addr_t *)addr;
-		spec.field_width = sizeof(dma_addr_t) * 2 + 2;
+		spec.field_width = sizeof(dma_addr_t) * 2;
 		break;
 	case 'p':
 	default:
 		num = *(const phys_addr_t *)addr;
-		spec.field_width = sizeof(phys_addr_t) * 2 + 2;
+		spec.field_width = sizeof(phys_addr_t) * 2;
 		break;
 	}
 
@@ -1259,7 +1259,7 @@ static noinline_for_stack
 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
 	      struct printf_spec spec)
 {
-	int default_width = 2 * sizeof(void *) + (spec.flags & SPECIAL ? 2 : 0);
+	int default_width = 2 * sizeof(void *);
 
 	if (!ptr && *fmt != 'K') {
 		/*



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