[PATCH] remove __ioremap_explicit() error message

[John Rose]

Here's a really long explanation for a really short patch! :)

As an unfortunate side effect of runtime addition/removal of PCI Host Bridges,
the RPA DLPAR driver can no longer depend on the success of ioremap_explicit() 
(and therefore remap_page_range()) for the case of DLPAR adding an I/O Slot.  

Without addressing this, an attempt to add the first child slot of a newly
added PHB will fail when __ioremap_explicit() determines the mappings for that
range to already exist.

For a little context, __ioremap_explicit() creates mappings for the range of a
newly added slot.  Here's why these calls will be expected to fail in some
cases.  Keep in mind that at boot-time, the PPC64 kernel calls ioremap() for
the entire range spanned by each PHB.  Consider the following scenarios of
DLPAR-adding an I/O slot.

1) Just after boot, one removes an I/O slot.  At this point the range 
   associated with the parent PHB is fragmented, and the child range for the 
   slot in question is iounmap()'ed.  One then re-adds the slot, at which point
   remap_page_range()/ioremap_explicit() restores the mappings that were 
   previously removed.

2) One adds a new PHB, at which point the ppc64-specific addition ioremaps the 
   entire PHB range.  One then performs a DLPAR-add of a child slot of that
   PHB.  At this point, mappings already exist for the range of the slot to
   be added.  So remap_page_range()/ioremap_explicit() will fail at this point.

The problem is, there's not a good way to distinguish between cases 1 and 2
from the perspective of the DLPAR driver.  Because of that, I believe the
correct solution to be:

- Removal of relevant error prints from iounmap_explicit(), which is only used 
  for DLPAR.
- Removal of error code checks from the RPA driver

Here's the first of these.

Thanks-
John

diff -Nru a/arch/ppc64/mm/init.c b/arch/ppc64/mm/init.c
--- a/arch/ppc64/mm/init.c	Wed Sep 29 14:10:06 2004
+++ b/arch/ppc64/mm/init.c	Wed Sep 29 14:10:06 2004
@@ -265,7 +265,7 @@
 	} else {
 		area = im_get_area(ea, size, IM_REGION_UNUSED|IM_REGION_SUBSET);
 		if (area == NULL) {
-			printk(KERN_ERR "could not obtain imalloc area for ea 0x%lx\n", ea);
+			/* Expected when PHB-dlpar is in play */
 			return 1;
 		}
 		if (ea != (unsigned long) area->addr) {