Wrong size calculation in __ioremap(), various platforms

Wrong size calculation in __ioremap(), various platforms

[Florian Zumbiehl]

Hi all,

in arch/*/mm/ioremap.c, __ioremap() of several platforms there seems to
be a minor mistake in the calculation of the page-aligned mapping size:

void * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
{
	void * addr;
	struct vm_struct * area;
	unsigned long offset, last_addr;

	/* Don't allow wraparound or zero size */
	last_addr = phys_addr + size - 1;
	if (!size || last_addr < phys_addr)
		return NULL;

	/* ... code which doesn't change last_addr ... */

	size = PAGE_ALIGN(last_addr) - phys_addr;

	/* ... */
}

For this calculation to work, PAGE_ALIGN(last_addr) would have to be
the address immediately after the last address to be mapped - if
last_addr is the first address of a page however, PAGE_ALIGN() of course
"returns" it unchanged.

So, the correct version IMO should look like this:

	size = PAGE_ALIGN(last_addr + 1) - phys_addr;

(2.5.47?/)i386 even seems to be affected twice - bt_ioremap() contains the
same piece of code.

In the hope not to have overlooked something,

Florian