Commit e66eda06 authored Feb 03, 2020 by Yury Norov Committed by Linus Torvalds Feb 04, 2020

lib: make bitmap_parse_user a wrapper on bitmap_parse

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.

Link: http://lkml.kernel.org/r/20200102043031.30357-5-yury.norov@gmail.com


Signed-off-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Amritha Nambiar <amritha.nambiar@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: "Tobin C . Harding" <tobin@kernel.org>
Cc: Vineet Gupta <vineet.gupta1@synopsys.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 7eb2e94e

lib/bitmap.c

+10 −10

Original line number	Diff line number	Diff line
		@@ -530,22 +530,22 @@ 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);

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