Re: [PATCH v2] powerpc: support sizes greater than an unsigned long

On Thu, 2015-06-11 at 19:10 +0300, Cristian Stoica wrote:

On 06/11/2015 06:38 PM, Greg KH wrote:

quoted

On Thu, Jun 11, 2015 at 05:42:00PM +0300, Cristian Stoica wrote:

Why?

This patch matches the input argument "size" of ioremap() with the 
output of request_mem_region() (which is
resource_size_t).
Since the latter is used as input to the former, the types should 
match (even though mapping more than 4G is not usually
expected). There are a lot of such differences in the code and this 
is an attempt to reduce that.

Dropping the upper bits of the size harms the ability to detect error 
scenarios where unmappably large -- but not power-of-two -- regions 
are requested to be mapped.

However, this patch doesn't fix that.  It just postpones the loss of 
the upper 32 bits until __ioremap_caller() calls get_vm_area_caller().

There's also no error checking at all for the size of ioremap() done 
during early boot (!slab_is_available()).

Don't just blindly turn static analyzer reports into patches -- and 
why didn't the analyzer complain about the call to 
get_vm_area_caller() after this patch?

-Scott