UBIFS: use nicer 64-bit math

Instead of using do_div(), use better primitives from
linux/math64.h.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

1 files changed, 6 insertions, 9 deletions

diff --git a/fs/ubifs/lpt.c b/fs/ubifs/lpt.c
index 6d914160ec55..b2792e84d245 100644
--- a/fs/ubifs/lpt.c
+++ b/fs/ubifs/lpt.c
@@ -43,8 +43,9 @@
  * mounted.
  */
 
-#include <linux/crc16.h>
 #include "ubifs.h"
+#include <linux/crc16.h>
+#include <linux/math64.h>
 
 /**
  * do_calc_lpt_geom - calculate sizes for the LPT area.
@@ -135,15 +136,13 @@ static void do_calc_lpt_geom(struct ubifs_info *c)
 int ubifs_calc_lpt_geom(struct ubifs_info *c)
 {
         int lebs_needed;
-        uint64_t sz;
+        long long sz;
 
         do_calc_lpt_geom(c);
 
         /* Verify that lpt_lebs is big enough */
         sz = c->lpt_sz * 2; /* Must have at least 2 times the size */
-        sz += c->leb_size - 1;
-        do_div(sz, c->leb_size);
-        lebs_needed = sz;
+        lebs_needed = div_u64(sz + c->leb_size - 1, c->leb_size);
         if (lebs_needed > c->lpt_lebs) {
                 ubifs_err("too few LPT LEBs");
                 return -EINVAL;
@@ -175,7 +174,7 @@ static int calc_dflt_lpt_geom(struct ubifs_info *c, int *main_lebs,
                               int *big_lpt)
 {
         int i, lebs_needed;
-        uint64_t sz;
+        long long sz;
 
         /* Start by assuming the minimum number of LPT LEBs */
         c->lpt_lebs = UBIFS_MIN_LPT_LEBS;
@@ -202,9 +201,7 @@ static int calc_dflt_lpt_geom(struct ubifs_info *c, int *main_lebs,
         /* Now check there are enough LPT LEBs */
         for (i = 0; i < 64 ; i++) {
                 sz = c->lpt_sz * 4; /* Allow 4 times the size */
-                sz += c->leb_size - 1;
-                do_div(sz, c->leb_size);
-                lebs_needed = sz;
+                lebs_needed = div_u64(sz + c->leb_size - 1, c->leb_size);
                 if (lebs_needed > c->lpt_lebs) {
                         /* Not enough LPT LEBs so try again with more */
                         c->lpt_lebs = lebs_needed;