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    Subject[PATCH] mtd/inftlmount: use memchr_inv
    Date
    Use memchr_inv to check if the data contains all 0xFF bytes.  It is
    faster than looping for each byte.
    This also removes memcmpb which is no longer used.

    Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
    Cc: David Woodhouse <dwmw2@infradead.org>
    Cc: linux-mtd@lists.infradead.org
    ---
    drivers/mtd/inftlmount.c | 14 ++------------
    1 files changed, 2 insertions(+), 12 deletions(-)

    diff --git a/drivers/mtd/inftlmount.c b/drivers/mtd/inftlmount.c
    index 4adc037..419b1c9 100644
    --- a/drivers/mtd/inftlmount.c
    +++ b/drivers/mtd/inftlmount.c
    @@ -320,16 +320,6 @@ static int find_boot_record(struct INFTLrecord *inftl)
    return -1;
    }

    -static int memcmpb(void *a, int c, int n)
    -{
    - int i;
    - for (i = 0; i < n; i++) {
    - if (c != ((unsigned char *)a)[i])
    - return 1;
    - }
    - return 0;
    -}
    -
    /*
    * check_free_sector: check if a free sector is actually FREE,
    * i.e. All 0xff in data and oob area.
    @@ -345,14 +335,14 @@ static int check_free_sectors(struct INFTLrecord *inftl, unsigned int address,
    for (i = 0; i < len; i += SECTORSIZE) {
    if (mtd_read(mtd, address, SECTORSIZE, &retlen, buf))
    return -1;
    - if (memcmpb(buf, 0xff, SECTORSIZE) != 0)
    + if (memchr_inv(buf, 0xff, SECTORSIZE))
    return -1;

    if (check_oob) {
    if(inftl_read_oob(mtd, address, mtd->oobsize,
    &retlen, &buf[SECTORSIZE]) < 0)
    return -1;
    - if (memcmpb(buf + SECTORSIZE, 0xff, mtd->oobsize) != 0)
    + if (memchr_inv(buf + SECTORSIZE, 0xff, mtd->oobsize))
    return -1;
    }
    address += SECTORSIZE;
    --
    1.7.4.4


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