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SubjectRe: [PATCH 4/7] lib: make bitmap_parse_user a wrapper on bitmap_parse
On Tue, Apr 30, 2019 at 06:06:33PM -0700, Yury Norov wrote:
> Currently we parse user data byte after byte which leads to
> overcomplicating of parsing algorithm. There are no performance
> critical users of bitmap_parse_user(), and so we can duplicate
> user data to kernel buffer and simply call bitmap_parselist().
> This rework lets us unify and simplify bitmap_parse() and
> bitmap_parse_user(), which is done in the following patch.
>

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

> Signed-off-by: Yury Norov <ynorov@marvell.com>
> ---
> lib/bitmap.c | 20 ++++++++++----------
> 1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/lib/bitmap.c b/lib/bitmap.c
> index f235434df87b..300732031fad 100644
> --- a/lib/bitmap.c
> +++ b/lib/bitmap.c
> @@ -434,22 +434,22 @@ EXPORT_SYMBOL(__bitmap_parse);
> * then it must be terminated with a \0.
> * @maskp: pointer to bitmap array that will contain result.
> * @nmaskbits: size of bitmap, in bits.
> - *
> - * Wrapper for __bitmap_parse(), providing it with user buffer.
> - *
> - * We cannot have this as an inline function in bitmap.h because it needs
> - * linux/uaccess.h to get the access_ok() declaration and this causes
> - * cyclic dependencies.
> */
> int bitmap_parse_user(const char __user *ubuf,
> unsigned int ulen, unsigned long *maskp,
> int nmaskbits)
> {
> - if (!access_ok(ubuf, ulen))
> - return -EFAULT;
> - return __bitmap_parse((const char __force *)ubuf,
> - ulen, 1, maskp, nmaskbits);
> + char *buf;
> + int ret;
>
> + buf = memdup_user_nul(ubuf, ulen);
> + if (IS_ERR(buf))
> + return PTR_ERR(buf);
> +
> + ret = bitmap_parse(buf, ulen, maskp, nmaskbits);
> +
> + kfree(buf);
> + return ret;
> }
> EXPORT_SYMBOL(bitmap_parse_user);
>
> --
> 2.17.1
>

--
With Best Regards,
Andy Shevchenko


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