[NET]: div64_64 consolidate (rev3)

Here is the current version of the 64 bit divide common code.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 25 insertions, 2 deletions

diff --git a/lib/Makefile b/lib/Makefile
index 992a39ef9ff..ae57f357fec 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -4,7 +4,7 @@
 
 lib-y := ctype.o string.o vsprintf.o cmdline.o \
 	 rbtree.o radix-tree.o dump_stack.o \
-	 idr.o div64.o int_sqrt.o bitmap.o extable.o prio_tree.o \
+	 idr.o int_sqrt.o bitmap.o extable.o prio_tree.o \
 	 sha1.o irq_regs.o reciprocal_div.o
 
 lib-$(CONFIG_MMU) += ioremap.o
@@ -12,7 +12,8 @@ lib-$(CONFIG_SMP) += cpumask.o
 
 lib-y	+= kobject.o kref.o kobject_uevent.o klist.o
 
-obj-y += sort.o parser.o halfmd4.o debug_locks.o random32.o bust_spinlocks.o
+obj-y += div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
+	 bust_spinlocks.o
 
 ifeq ($(CONFIG_DEBUG_KOBJECT),y)
 CFLAGS_kobject.o += -DDEBUG
diff --git a/lib/div64.c b/lib/div64.c
index 365719f8483..c3d7655cdfb 100644
--- a/lib/div64.c
+++ b/lib/div64.c
@@ -58,4 +58,26 @@ uint32_t __div64_32(uint64_t *n, uint32_t base)
 
 EXPORT_SYMBOL(__div64_32);
 
+/* 64bit divisor, dividend and result. dynamic precision */
+uint64_t div64_64(uint64_t dividend, uint64_t divisor)
+{
+	uint32_t d = divisor;
+
+	if (divisor > 0xffffffffULL) {
+		unsigned int shift = fls(divisor >> 32);
+
+		d = divisor >> shift;
+		dividend >>= shift;
+	}
+
+	/* avoid 64 bit division if possible */
+	if (dividend >> 32)
+		do_div(dividend, d);
+	else
+		dividend = (uint32_t) dividend / d;
+
+	return dividend;
+}
+EXPORT_SYMBOL(div64_64);
+
 #endif /* BITS_PER_LONG == 32 */