resources: skip sanity check of busy resources
Arjan van de Ven [Sat, 13 Dec 2008 17:15:27 +0000 (09:15 -0800)]
Impact: reduce false positives in iomem_map_sanity_check()

Some drivers (vesafb) only map/reserve a portion of a resource.
If then some other driver comes in and maps the whole resource,
the current code WARN_ON's. This is not the intent of the checks
in iomem_map_sanity_check(); rather these checks want to
warn when crossing *hardware* resources only.

This patch skips BUSY resources as suggested by Linus.

Note: having two drivers talk to the same hardware at the same
time is obviously not optimal behavior, but that's a separate story.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/resource.c

index 4337063..e633106 100644 (file)
@@ -853,6 +853,15 @@ int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
                if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
                    PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
                        continue;
+               /*
+                * if a resource is "BUSY", it's not a hardware resource
+                * but a driver mapping of such a resource; we don't want
+                * to warn for those; some drivers legitimately map only
+                * partial hardware resources. (example: vesafb)
+                */
+               if (p->flags & IORESOURCE_BUSY)
+                       continue;
+
                printk(KERN_WARNING "resource map sanity check conflict: "
                       "0x%llx 0x%llx 0x%llx 0x%llx %s\n",
                       (unsigned long long)addr,