Messages in this thread | | | Date | Mon, 8 Apr 2019 12:30:54 +0300 | From | Andy Shevchenko <> | Subject | Re: [PATCH 1/5] lib: make bitmap_parselist_user() a wrapper on bitmap_parselist() |
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On Fri, Apr 05, 2019 at 08:32:07PM +0300, Yury Norov wrote: > Currently we parse user data byte after byte which leads to > overcomplification of parsing algorithm. The only user of > bitmap_parselist_user() is not performance-critical, and so we > can duplicate user data to kernel buffer and simply call > bitmap_parselist(). This rework lets us unify and simplify > bitmap_parselist() and bitmap_parselist_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 | 19 +++++++++++-------- > 1 file changed, 11 insertions(+), 8 deletions(-) > > diff --git a/lib/bitmap.c b/lib/bitmap.c > index 98872e9025da..79ed5538617b 100644 > --- a/lib/bitmap.c > +++ b/lib/bitmap.c > @@ -632,19 +632,22 @@ EXPORT_SYMBOL(bitmap_parselist); > * @nmaskbits: size of bitmap, in bits. > * > * Wrapper for bitmap_parselist(), 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_parselist_user(const char __user *ubuf, > unsigned int ulen, unsigned long *maskp, > int nmaskbits) > { > - if (!access_ok(ubuf, ulen)) > - return -EFAULT; > - return __bitmap_parselist((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_parselist(buf, maskp, nmaskbits); > + > + kfree(buf); > + return ret; > } > EXPORT_SYMBOL(bitmap_parselist_user); > > -- > 2.17.1 >
-- With Best Regards, Andy Shevchenko
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