Re: [PATCH v12 4/4] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

On Mon, Nov 09, 2020 at 12:11:40PM -0500, William Breathitt Gray wrote:

On Mon, Nov 09, 2020 at 10:15:29PM +0530, Syed Nayyar Waris wrote:

quoted

On Mon, Nov 09, 2020 at 03:41:53PM +0100, Arnd Bergmann wrote:

...

quoted

 static inline void bitmap_set_value(unsigned long *map,
-                                    unsigned long value,
+                                    unsigned long value, const size_t length,
                                     unsigned long start, unsigned long nbits)
 {
         const size_t index = BIT_WORD(start);

@@ -15,6 +15,10 @@ static inline void bitmap_set_value(unsigned long *map,
         } else {
                 map[index + 0] &= ~BITMAP_FIRST_WORD_MASK(start);
                 map[index + 0] |= value << offset;
+
+               if (index + 1 >= length)
+                       __builtin_unreachable();
+
                 map[index + 1] &= ~BITMAP_LAST_WORD_MASK(start + nbits);
                 map[index + 1] |= value >> space;
         }

Hi Syed,

Let's rename 'length' to 'nbits' as Arnd suggested, and rename 'nbits'
to value_width.

length here is in longs. I guess this is the point of entire patch.

But to me sounds like it would be better to have simply bitmap_set_value64() /
bitmap_set_value32() with proper optimization done and forget about variadic
ones for now.

-- 
With Best Regards,
Andy Shevchenko



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