Add functions and macros as used upstream.

Added highbit64() and howmany() which are used in recent upstream
code.  Both highbit() and highbit64() should at some point be
re-factored to use the optimized fls() and fls64() functions.

Signed-off-by: Brian Behlendorf <[email protected]>
Signed-off-by: Prakash Surya <[email protected]>
Signed-off-by: Tim Chase <[email protected]>
Closes #363

1 files changed, 30 insertions, 0 deletions

diff --git a/module/spl/spl-generic.c b/module/spl/spl-generic.c
index 4f0842b1a..6cb73ddb7 100644
--- a/module/spl/spl-generic.c
+++ b/module/spl/spl-generic.c
@@ -97,6 +97,36 @@ highbit(unsigned long i)
 }
 EXPORT_SYMBOL(highbit);
 
+int
+highbit64(uint64_t i)
+{
+        register int h = 1;
+        SENTRY;
+
+        if (i == 0)
+                SRETURN(0);
+        if (i & 0xffffffff00000000ull) {
+                h += 32; i >>= 32;
+        }
+        if (i & 0xffff0000) {
+                h += 16; i >>= 16;
+        }
+        if (i & 0xff00) {
+                h += 8; i >>= 8;
+        }
+        if (i & 0xf0) {
+                h += 4; i >>= 4;
+        }
+        if (i & 0xc) {
+                h += 2; i >>= 2;
+        }
+        if (i & 0x2) {
+                h += 1;
+        }
+        SRETURN(h);
+}
+EXPORT_SYMBOL(highbit64);
+
 #if BITS_PER_LONG == 32
 /*
  * Support 64/64 => 64 division on a 32-bit platform.  While the kernel