diff mbox series

[v4,1/1] drm/i915: Move abs_diff() to math.h

Message ID 20230803131918.53727-1-andriy.shevchenko@linux.intel.com (mailing list archive)
State Not Applicable
Headers show
Series [v4,1/1] drm/i915: Move abs_diff() to math.h | expand

Commit Message

Andy Shevchenko Aug. 3, 2023, 1:19 p.m. UTC 
abs_diff() belongs to math.h. Move it there.
This will allow others to use it.

Reviewed-by: Jiri Slaby <jirislaby@kernel.org> # tty/serial
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> # gpu/ipu-v3
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
v4:
- Cc'ed to Andrew (as Jani told he is okay to route it via other tree)
- added tags
 drivers/gpu/drm/i915/display/intel_dpll_mgr.c |  1 +
 drivers/gpu/drm/i915/display/intel_dpll_mgr.h |  7 -------
 drivers/gpu/ipu-v3/ipu-image-convert.c        | 15 +++++++--------
 drivers/tty/serial/omap-serial.c              |  7 +------
 drivers/video/fbdev/core/svgalib.c            |  7 +------
 include/linux/math.h                          |  7 +++++++
 6 files changed, 17 insertions(+), 27 deletions(-)

Comments

Andrew Morton Aug. 3, 2023, 5:24 p.m. UTC | #1 
On Thu,  3 Aug 2023 16:19:18 +0300 Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:

> abs_diff() belongs to math.h. Move it there.
> This will allow others to use it.
> 
> ...
>
> --- a/include/linux/math.h
> +++ b/include/linux/math.h
> @@ -155,6 +155,13 @@ __STRUCT_FRACT(u32)
>  	__builtin_types_compatible_p(typeof(x), unsigned type),		\
>  	({ signed type __x = (x); __x < 0 ? -__x : __x; }), other)
>  
> +#define abs_diff(a, b) ({			\
> +	typeof(a) __a = (a);			\
> +	typeof(b) __b = (b);			\
> +	(void)(&__a == &__b);			\
> +	__a > __b ? (__a - __b) : (__b - __a);	\
> +})

Can we document it please?

Also, the open-coded type comparison could be replaced with __typecheck()?

And why the heck isn't __typecheck() in typecheck.h, to be included by
minmax.h.

etcetera.  Sigh.  I'll grab it, but please at least send along some
kerneldoc?
Andy Shevchenko Aug. 4, 2023, 4:07 a.m. UTC | #2 
On Thu, Aug 03, 2023 at 10:24:46AM -0700, Andrew Morton wrote:
> On Thu,  3 Aug 2023 16:19:18 +0300 Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:

...

> > +#define abs_diff(a, b) ({			\
> > +	typeof(a) __a = (a);			\
> > +	typeof(b) __b = (b);			\
> > +	(void)(&__a == &__b);			\
> > +	__a > __b ? (__a - __b) : (__b - __a);	\
> > +})
> 
> Can we document it please?
> 
> Also, the open-coded type comparison could be replaced with __typecheck()?
> 
> And why the heck isn't __typecheck() in typecheck.h, to be included by
> minmax.h.
> 
> etcetera.  Sigh.  I'll grab it, but please at least send along some
> kerneldoc?

Sure and thank you!
David Laight Aug. 4, 2023, 3:50 p.m. UTC | #3 
From: Andrew Morton
> Sent: 03 August 2023 18:25
> 
> On Thu,  3 Aug 2023 16:19:18 +0300 Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> 
> > abs_diff() belongs to math.h. Move it there.
> > This will allow others to use it.
> >
> > ...
> >
> > --- a/include/linux/math.h
> > +++ b/include/linux/math.h
> > @@ -155,6 +155,13 @@ __STRUCT_FRACT(u32)
> >  	__builtin_types_compatible_p(typeof(x), unsigned type),		\
> >  	({ signed type __x = (x); __x < 0 ? -__x : __x; }), other)
> >
> > +#define abs_diff(a, b) ({			\
> > +	typeof(a) __a = (a);			\
> > +	typeof(b) __b = (b);			\
> > +	(void)(&__a == &__b);			\
> > +	__a > __b ? (__a - __b) : (__b - __a);	\
> > +})
> 
> Can we document it please?
> 
> Also, the open-coded type comparison could be replaced with __typecheck()?
> 
> And why the heck isn't __typecheck() in typecheck.h, to be included by
> minmax.h.

And why would you want to use __typecheck() anyway?
It pretty much isn't the test you are looking for.
If you are trying to explicitly avoid converting negative value
to large positive unsigned ones then you want something like:
	is_signed_type(typeof(a)) == is_signed_type(typeof(b))
but it isn't even that simple :-)

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
index 6b2d8a1e2aa9..290e856fe9e9 100644
--- a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
+++ b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
@@ -21,6 +21,7 @@ 
  * DEALINGS IN THE SOFTWARE.
  */
 
+#include <linux/math.h>
 #include <linux/string_helpers.h>
 
 #include "i915_reg.h"
diff --git a/drivers/gpu/drm/i915/display/intel_dpll_mgr.h b/drivers/gpu/drm/i915/display/intel_dpll_mgr.h
index ba62eb5d7c51..04e6810954b2 100644
--- a/drivers/gpu/drm/i915/display/intel_dpll_mgr.h
+++ b/drivers/gpu/drm/i915/display/intel_dpll_mgr.h
@@ -29,13 +29,6 @@ 
 
 #include "intel_wakeref.h"
 
-/*FIXME: Move this to a more appropriate place. */
-#define abs_diff(a, b) ({			\
-	typeof(a) __a = (a);			\
-	typeof(b) __b = (b);			\
-	(void) (&__a == &__b);			\
-	__a > __b ? (__a - __b) : (__b - __a); })
-
 enum tc_port;
 struct drm_i915_private;
 struct intel_atomic_state;
diff --git a/drivers/gpu/ipu-v3/ipu-image-convert.c b/drivers/gpu/ipu-v3/ipu-image-convert.c
index af1612044eef..841316582ea9 100644
--- a/drivers/gpu/ipu-v3/ipu-image-convert.c
+++ b/drivers/gpu/ipu-v3/ipu-image-convert.c
@@ -7,7 +7,10 @@ 
 
 #include <linux/interrupt.h>
 #include <linux/dma-mapping.h>
+#include <linux/math.h>
+
 #include <video/imx-ipu-image-convert.h>
+
 #include "ipu-prv.h"
 
 /*
@@ -543,7 +546,7 @@  static void find_best_seam(struct ipu_image_convert_ctx *ctx,
 		unsigned int in_pos;
 		unsigned int in_pos_aligned;
 		unsigned int in_pos_rounded;
-		unsigned int abs_diff;
+		unsigned int diff;
 
 		/*
 		 * Tiles in the right row / bottom column may not be allowed to
@@ -575,15 +578,11 @@  static void find_best_seam(struct ipu_image_convert_ctx *ctx,
 		    (in_edge - in_pos_rounded) % in_burst)
 			continue;
 
-		if (in_pos < in_pos_aligned)
-			abs_diff = in_pos_aligned - in_pos;
-		else
-			abs_diff = in_pos - in_pos_aligned;
-
-		if (abs_diff < min_diff) {
+		diff = abs_diff(in_pos, in_pos_aligned);
+		if (diff < min_diff) {
 			in_seam = in_pos_rounded;
 			out_seam = out_pos;
-			min_diff = abs_diff;
+			min_diff = diff;
 		}
 	}
 
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 3dc14dcb01ca..0ead88c5a19a 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -222,16 +222,11 @@  static inline int calculate_baud_abs_diff(struct uart_port *port,
 				unsigned int baud, unsigned int mode)
 {
 	unsigned int n = port->uartclk / (mode * baud);
-	int abs_diff;
 
 	if (n == 0)
 		n = 1;
 
-	abs_diff = baud - (port->uartclk / (mode * n));
-	if (abs_diff < 0)
-		abs_diff = -abs_diff;
-
-	return abs_diff;
+	return abs_diff(baud, port->uartclk / (mode * n));
 }
 
 /*
diff --git a/drivers/video/fbdev/core/svgalib.c b/drivers/video/fbdev/core/svgalib.c
index 9e01322fabe3..2cba158888ea 100644
--- a/drivers/video/fbdev/core/svgalib.c
+++ b/drivers/video/fbdev/core/svgalib.c
@@ -14,6 +14,7 @@ 
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/fb.h>
+#include <linux/math.h>
 #include <linux/svga.h>
 #include <asm/types.h>
 #include <asm/io.h>
@@ -372,12 +373,6 @@  EXPORT_SYMBOL(svga_get_caps);
  *  F_VCO = (F_BASE * M) / N
  *  F_OUT = F_VCO / (2^R)
  */
-
-static inline u32 abs_diff(u32 a, u32 b)
-{
-	return (a > b) ? (a - b) : (b - a);
-}
-
 int svga_compute_pll(const struct svga_pll *pll, u32 f_wanted, u16 *m, u16 *n, u16 *r, int node)
 {
 	u16 am, an, ar;
diff --git a/include/linux/math.h b/include/linux/math.h
index 2d388650c556..336e3e3678e7 100644
--- a/include/linux/math.h
+++ b/include/linux/math.h
@@ -155,6 +155,13 @@  __STRUCT_FRACT(u32)
 	__builtin_types_compatible_p(typeof(x), unsigned type),		\
 	({ signed type __x = (x); __x < 0 ? -__x : __x; }), other)
 
+#define abs_diff(a, b) ({			\
+	typeof(a) __a = (a);			\
+	typeof(b) __b = (b);			\
+	(void)(&__a == &__b);			\
+	__a > __b ? (__a - __b) : (__b - __a);	\
+})
+
 /**
  * reciprocal_scale - "scale" a value into range [0, ep_ro)
  * @val: value