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>

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);

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;

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");

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;
 

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;