UBI: use nicer 64-bit math

Get rid of 'do_div()' and use more user-friendly primitives from
'linux/math64.h'.

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

5 files changed, 25 insertions, 52 deletions

diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index 0a2d835fec80..f9631eb3fef3 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -41,8 +41,8 @@
 #include <linux/capability.h>
 #include <linux/uaccess.h>
 #include <linux/compat.h>
+#include <linux/math64.h>
 #include <mtd/ubi-user.h>
-#include <asm/div64.h>
 #include "ubi.h"
 
 /**
@@ -195,7 +195,6 @@ static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
         int err, lnum, off, len,  tbuf_size;
         size_t count_save = count;
         void *tbuf;
-        uint64_t tmp;
 
         dbg_gen("read %zd bytes from offset %lld of volume %d",
                 count, *offp, vol->vol_id);
@@ -225,10 +224,7 @@ static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
                 return -ENOMEM;
 
         len = count > tbuf_size ? tbuf_size : count;
-
-        tmp = *offp;
-        off = do_div(tmp, vol->usable_leb_size);
-        lnum = tmp;
+        lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
 
         do {
                 cond_resched();
@@ -279,7 +275,6 @@ static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
         int lnum, off, len, tbuf_size, err = 0;
         size_t count_save = count;
         char *tbuf;
-        uint64_t tmp;
 
         dbg_gen("requested: write %zd bytes to offset %lld of volume %u",
                 count, *offp, vol->vol_id);
@@ -287,10 +282,7 @@ static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
         if (vol->vol_type == UBI_STATIC_VOLUME)
                 return -EROFS;
 
-        tmp = *offp;
-        off = do_div(tmp, vol->usable_leb_size);
-        lnum = tmp;
-
+        lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
         if (off & (ubi->min_io_size - 1)) {
                 dbg_err("unaligned position");
                 return -EINVAL;
@@ -882,7 +874,6 @@ static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
         case UBI_IOCRSVOL:
         {
                 int pebs;
-                uint64_t tmp;
                 struct ubi_rsvol_req req;
 
                 dbg_gen("re-size volume");
@@ -902,9 +893,8 @@ static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
                         break;
                 }
 
-                tmp = req.bytes;
-                pebs = !!do_div(tmp, desc->vol->usable_leb_size);
-                pebs += tmp;
+                pebs = div_u64(req.bytes + desc->vol->usable_leb_size - 1,
+                               desc->vol->usable_leb_size);
 
                 mutex_lock(&ubi->volumes_mutex);
                 err = ubi_resize_volume(desc, pebs);
diff --git a/drivers/mtd/ubi/gluebi.c b/drivers/mtd/ubi/gluebi.c
index 6dd4f5e77f82..49cd55ade9c8 100644
--- a/drivers/mtd/ubi/gluebi.c
+++ b/drivers/mtd/ubi/gluebi.c
@@ -28,7 +28,7 @@
  * eraseblock size is equivalent to the logical eraseblock size of the volume.
  */
 
-#include <asm/div64.h>
+#include <linux/math64.h>
 #include "ubi.h"
 
 /**
@@ -109,7 +109,6 @@ static int gluebi_read(struct mtd_info *mtd, loff_t from, size_t len,
         int err = 0, lnum, offs, total_read;
         struct ubi_volume *vol;
         struct ubi_device *ubi;
-        uint64_t tmp = from;
 
         dbg_gen("read %zd bytes from offset %lld", len, from);
 
@@ -119,9 +118,7 @@ static int gluebi_read(struct mtd_info *mtd, loff_t from, size_t len,
         vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
         ubi = vol->ubi;
 
-        offs = do_div(tmp, mtd->erasesize);
-        lnum = tmp;
-
+        lnum = div_u64_rem(from, mtd->erasesize, &offs);
         total_read = len;
         while (total_read) {
                 size_t to_read = mtd->erasesize - offs;
@@ -160,7 +157,6 @@ static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len,
         int err = 0, lnum, offs, total_written;
         struct ubi_volume *vol;
         struct ubi_device *ubi;
-        uint64_t tmp = to;
 
         dbg_gen("write %zd bytes to offset %lld", len, to);
 
@@ -173,8 +169,7 @@ static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len,
         if (ubi->ro_mode)
                 return -EROFS;
 
-        offs = do_div(tmp, mtd->erasesize);
-        lnum = tmp;
+        lnum = div_u64_rem(to, mtd->erasesize, &offs);
 
         if (len % mtd->writesize || offs % mtd->writesize)
                 return -EINVAL;
diff --git a/drivers/mtd/ubi/scan.c b/drivers/mtd/ubi/scan.c
index ecde202a5a12..c3d653ba5ca0 100644
--- a/drivers/mtd/ubi/scan.c
+++ b/drivers/mtd/ubi/scan.c
@@ -42,7 +42,7 @@
 
 #include <linux/err.h>
 #include <linux/crc32.h>
-#include <asm/div64.h>
+#include <linux/math64.h>
 #include "ubi.h"
 
 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
@@ -904,10 +904,8 @@ struct ubi_scan_info *ubi_scan(struct ubi_device *ubi)
         dbg_msg("scanning is finished");
 
         /* Calculate mean erase counter */
-        if (si->ec_count) {
-                do_div(si->ec_sum, si->ec_count);
-                si->mean_ec = si->ec_sum;
-        }
+        if (si->ec_count)
+                si->mean_ec = div_u64(si->ec_sum, si->ec_count);
 
         if (si->is_empty)
                 ubi_msg("empty MTD device detected");
diff --git a/drivers/mtd/ubi/upd.c b/drivers/mtd/ubi/upd.c
index 8b89cc18ff0b..6b4d1ae891ae 100644
--- a/drivers/mtd/ubi/upd.c
+++ b/drivers/mtd/ubi/upd.c
@@ -40,7 +40,7 @@
 
 #include <linux/err.h>
 #include <linux/uaccess.h>
-#include <asm/div64.h>
+#include <linux/math64.h>
 #include "ubi.h"
 
 /**
@@ -89,7 +89,6 @@ static int clear_update_marker(struct ubi_device *ubi, struct ubi_volume *vol,
                                long long bytes)
 {
         int err;
-        uint64_t tmp;
         struct ubi_vtbl_record vtbl_rec;
 
         dbg_gen("clear update marker for volume %d", vol->vol_id);
@@ -101,9 +100,9 @@ static int clear_update_marker(struct ubi_device *ubi, struct ubi_volume *vol,
 
         if (vol->vol_type == UBI_STATIC_VOLUME) {
                 vol->corrupted = 0;
-                vol->used_bytes = tmp = bytes;
-                vol->last_eb_bytes = do_div(tmp, vol->usable_leb_size);
-                vol->used_ebs = tmp;
+                vol->used_bytes = bytes;
+                vol->used_ebs = div_u64_rem(bytes, vol->usable_leb_size,
+                                            &vol->last_eb_bytes);
                 if (vol->last_eb_bytes)
                         vol->used_ebs += 1;
                 else
@@ -131,7 +130,6 @@ int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
                      long long bytes)
 {
         int i, err;
-        uint64_t tmp;
 
         dbg_gen("start update of volume %d, %llu bytes", vol->vol_id, bytes);
         ubi_assert(!vol->updating && !vol->changing_leb);
@@ -161,9 +159,8 @@ int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
         if (!vol->upd_buf)
                 return -ENOMEM;
 
-        tmp = bytes;
-        vol->upd_ebs = !!do_div(tmp, vol->usable_leb_size);
-        vol->upd_ebs += tmp;
+        vol->upd_ebs = div_u64(bytes + vol->usable_leb_size - 1,
+                               vol->usable_leb_size);
         vol->upd_bytes = bytes;
         vol->upd_received = 0;
         return 0;
@@ -282,7 +279,6 @@ static int write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
 int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
                          const void __user *buf, int count)
 {
-        uint64_t tmp;
         int lnum, offs, err = 0, len, to_write = count;
 
         dbg_gen("write %d of %lld bytes, %lld already passed",
@@ -291,10 +287,7 @@ int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
         if (ubi->ro_mode)
                 return -EROFS;
 
-        tmp = vol->upd_received;
-        offs = do_div(tmp, vol->usable_leb_size);
-        lnum = tmp;
-
+        lnum = div_u64_rem(vol->upd_received,  vol->usable_leb_size, &offs);
         if (vol->upd_received + count > vol->upd_bytes)
                 to_write = count = vol->upd_bytes - vol->upd_received;
 
diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
index 22e1d7398fce..df5483562b7a 100644
--- a/drivers/mtd/ubi/vmt.c
+++ b/drivers/mtd/ubi/vmt.c
@@ -24,7 +24,7 @@
  */
 
 #include <linux/err.h>
-#include <asm/div64.h>
+#include <linux/math64.h>
 #include "ubi.h"
 
 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
@@ -205,7 +205,6 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
         int i, err, vol_id = req->vol_id, do_free = 1;
         struct ubi_volume *vol;
         struct ubi_vtbl_record vtbl_rec;
-        uint64_t bytes;
         dev_t dev;
 
         if (ubi->ro_mode)
@@ -255,10 +254,8 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
 
         /* Calculate how many eraseblocks are requested */
         vol->usable_leb_size = ubi->leb_size - ubi->leb_size % req->alignment;
-        bytes = req->bytes;
-        if (do_div(bytes, vol->usable_leb_size))
-                vol->reserved_pebs = 1;
-        vol->reserved_pebs += bytes;
+        vol->reserved_pebs += div_u64(req->bytes + vol->usable_leb_size - 1,
+                                      vol->usable_leb_size);
 
         /* Reserve physical eraseblocks */
         if (vol->reserved_pebs > ubi->avail_pebs) {
@@ -301,10 +298,10 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
                 vol->used_bytes =
                         (long long)vol->used_ebs * vol->usable_leb_size;
         } else {
-                bytes = vol->used_bytes;
-                vol->last_eb_bytes = do_div(bytes, vol->usable_leb_size);
-                vol->used_ebs = bytes;
-                if (vol->last_eb_bytes)
+                vol->used_ebs = div_u64_rem(vol->used_bytes,
+                                            vol->usable_leb_size,
+                                            &vol->last_eb_bytes);
+                if (vol->last_eb_bytes != 0)
                         vol->used_ebs += 1;
                 else
                         vol->last_eb_bytes = vol->usable_leb_size;