convert ill defined log2() to ilog2()

It's *wrong* to have
			#define log2(n) ffz(~(n))
It should be *reversed*:
			#define log2(n) flz(~(n))
or
			#define log2(n) fls(n)
or just use
			ilog2(n) defined in linux/log2.h.

This patch follows the last solution, recommended by Andrew Morton.

Cc: <linux-ext4@vger.kernel.org>
Cc: Mingming Cao <cmm@us.ibm.com>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Chris Ahna <christopher.j.ahna@intel.com>
Cc: David Mosberger-Tang <davidm@hpl.hp.com>
Cc: Kyle McMartin <kyle@parisc-linux.org>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 3 deletions

diff --git a/drivers/char/agp/i460-agp.c b/drivers/char/agp/i460-agp.c
index 70117df4d067..e72a83e2bad5 100644
--- a/drivers/char/agp/i460-agp.c
+++ b/drivers/char/agp/i460-agp.c
@@ -13,6 +13,7 @@
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/agp_backend.h>
+#include <linux/log2.h>
 
 #include "agp.h"
 
@@ -59,8 +60,6 @@
  */
 #define WR_FLUSH_GATT(index)    RD_GATT(index)
 
-#define log2(x)                 ffz(~(x))
-
 static struct {
         void *gatt;                             /* ioremap'd GATT area */
 
@@ -148,7 +147,7 @@ static int i460_fetch_size (void)
                  * values[i].size.
                  */
                 values[i].num_entries = (values[i].size << 8) >> (I460_IO_PAGE_SHIFT - 12);
-                values[i].page_order = log2((sizeof(u32)*values[i].num_entries) >> PAGE_SHIFT);
+                values[i].page_order = ilog2((sizeof(u32)*values[i].num_entries) >> PAGE_SHIFT);
         }
 
         for (i = 0; i < agp_bridge->driver->num_aperture_sizes; i++) {