void memcpy_fromio()

in kernel/io.c [467:512]

• 40 lines of code
• 11 McCabe index (conditional complexity)

void memcpy_fromio(void *to, const volatile void __iomem *from, long count)
{
	/* Optimize co-aligned transfers.  Everything else gets handled
	   a byte at a time. */

	if (count >= 8 && ((u64)to & 7) == ((u64)from & 7)) {
		count -= 8;
		do {
			*(u64 *)to = __raw_readq(from);
			count -= 8;
			to += 8;
			from += 8;
		} while (count >= 0);
		count += 8;
	}

	if (count >= 4 && ((u64)to & 3) == ((u64)from & 3)) {
		count -= 4;
		do {
			*(u32 *)to = __raw_readl(from);
			count -= 4;
			to += 4;
			from += 4;
		} while (count >= 0);
		count += 4;
	}

	if (count >= 2 && ((u64)to & 1) == ((u64)from & 1)) {
		count -= 2;
		do {
			*(u16 *)to = __raw_readw(from);
			count -= 2;
			to += 2;
			from += 2;
		} while (count >= 0);
		count += 2;
	}

	while (count > 0) {
		*(u8 *) to = __raw_readb(from);
		count--;
		to++;
		from++;
	}
	mb();
}