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Commit cadb40cc authored by Kyungmin Park's avatar Kyungmin Park Committed by Artem Bityutskiy
Browse files

UBI: avoid unnecessary division operations 



UBI already checks that @min io size is the power of 2 at io_init.
It is save to use bit operations then.

Signed-off-by: default avatarKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
parent a0fd1efd

drivers/mtd/ubi/build.c

+6 −2
Original line number Original line Diff line number Diff line
@@ -530,7 +530,11 @@ static int io_init(struct ubi_device *ubi) 
	ubi->min_io_size = ubi->mtd->writesize;

	ubi->min_io_size = ubi->mtd->writesize;

	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;

	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;





	/* Make sure minimal I/O unit is power of 2 */

	/*

	 * Make sure minimal I/O unit is power of 2. Note, there is no

	 * fundamental reason for this assumption. It is just an optimization

	 * which allows us to avoid costly division operations.

	 */

	if (!is_power_of_2(ubi->min_io_size)) {

	if (!is_power_of_2(ubi->min_io_size)) {

		ubi_err("min. I/O unit (%d) is not power of 2",

		ubi_err("min. I/O unit (%d) is not power of 2",

			ubi->min_io_size);

			ubi->min_io_size);
@@ -581,7 +585,7 @@ static int io_init(struct ubi_device *ubi) 
	if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||

	if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||

	    ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||

	    ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||

	    ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||

	    ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||

	    ubi->leb_start % ubi->min_io_size) {

	    ubi->leb_start & (ubi->min_io_size - 1)) {

		ubi_err("bad VID header (%d) or data offsets (%d)",

		ubi_err("bad VID header (%d) or data offsets (%d)",

			ubi->vid_hdr_offset, ubi->leb_start);

			ubi->vid_hdr_offset, ubi->leb_start);

		return -EINVAL;

		return -EINVAL;

drivers/mtd/ubi/cdev.c

+3 −3
Original line number Original line Diff line number Diff line
@@ -295,7 +295,7 @@ static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf, 
	off = do_div(tmp, vol->usable_leb_size);

	off = do_div(tmp, vol->usable_leb_size);

	lnum = tmp;

	lnum = tmp;





	if (off % ubi->min_io_size) {

	if (off & (ubi->min_io_size - 1)) {

		dbg_err("unaligned position");

		dbg_err("unaligned position");

		return -EINVAL;

		return -EINVAL;

	}

	}
@@ -304,7 +304,7 @@ static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf, 
		count_save = count = vol->used_bytes - *offp;

		count_save = count = vol->used_bytes - *offp;





	/* We can write only in fractions of the minimum I/O unit */

	/* We can write only in fractions of the minimum I/O unit */

	if (count % ubi->min_io_size) {

	if (count & (ubi->min_io_size - 1)) {

		dbg_err("unaligned write length");

		dbg_err("unaligned write length");

		return -EINVAL;

		return -EINVAL;

	}

	}
@@ -564,7 +564,7 @@ static int verify_mkvol_req(const struct ubi_device *ubi, 
	if (req->alignment > ubi->leb_size)

	if (req->alignment > ubi->leb_size)

		goto bad;

		goto bad;





	n = req->alignment % ubi->min_io_size;

	n = req->alignment & (ubi->min_io_size - 1);

	if (req->alignment != 1 && n)

	if (req->alignment != 1 && n)

		goto bad;

		goto bad;

drivers/mtd/ubi/eba.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -752,7 +752,7 @@ int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol, 
		/* If this is the last LEB @len may be unaligned */

		/* If this is the last LEB @len may be unaligned */

		len = ALIGN(data_size, ubi->min_io_size);

		len = ALIGN(data_size, ubi->min_io_size);

	else

	else

		ubi_assert(len % ubi->min_io_size == 0);

		ubi_assert(!(len & (ubi->min_io_size - 1)));





	vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);

	vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);

	if (!vid_hdr)

	if (!vid_hdr)

drivers/mtd/ubi/kapi.c

+3 −3
Original line number Original line Diff line number Diff line
@@ -397,8 +397,8 @@ int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf, 
		return -EROFS;

		return -EROFS;





	if (lnum < 0 || lnum >= vol->reserved_pebs || offset < 0 || len < 0 ||

	if (lnum < 0 || lnum >= vol->reserved_pebs || offset < 0 || len < 0 ||

	    offset + len > vol->usable_leb_size || offset % ubi->min_io_size ||

	    offset + len > vol->usable_leb_size ||

	    len % ubi->min_io_size)

	    offset & (ubi->min_io_size - 1) || len & (ubi->min_io_size - 1))

		return -EINVAL;

		return -EINVAL;





	if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&

	if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&
@@ -447,7 +447,7 @@ int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf, 
		return -EROFS;

		return -EROFS;





	if (lnum < 0 || lnum >= vol->reserved_pebs || len < 0 ||

	if (lnum < 0 || lnum >= vol->reserved_pebs || len < 0 ||

	    len > vol->usable_leb_size || len % ubi->min_io_size)

	    len > vol->usable_leb_size || len & (ubi->min_io_size - 1))

		return -EINVAL;

		return -EINVAL;





	if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&

	if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&

drivers/mtd/ubi/misc.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -37,7 +37,7 @@ int ubi_calc_data_len(const struct ubi_device *ubi, const void *buf, 
{

{

	int i;

	int i;





	ubi_assert(length % ubi->min_io_size == 0);

	ubi_assert(!(length & (ubi->min_io_size - 1)));





	for (i = length - 1; i >= 0; i--)

	for (i = length - 1; i >= 0; i--)

		if (((const uint8_t *)buf)[i] != 0xFF)

		if (((const uint8_t *)buf)[i] != 0xFF)