Resource providers set this flag if they want
that request_region will print a warning in dmesg
if this particular memory resource is locked by a driver.

Thous acting as a Protocol Police about experimental
devices that did not pass a committee approval.

The Only user of  this flag is x86/kernel/e820.c that
wants to WARN about UNKNOWN memory types.

NOTE: It would be preferred if I defined a general flag say
      IORESOURCE_WARN, where any kind of resource provider
      can WARN on use, but we have run out of flags in the
      32bit long systems. So I defined a free bit from the
      resource specific flags for mem resources. This is
      why I need to check if this is a memory resource first
      so not to conflict with other resource specific flags.
      (Though actually no one is using this specific bit)

CC: Thomas Gleixner <t...@linutronix.de>
CC: Ingo Molnar <mi...@redhat.com>
CC: "H. Peter Anvin" <h...@zytor.com>
CC: x...@kernel.org
CC: Dan Williams <dan.j.willi...@intel.com>
CC: Andrew Morton <a...@linux-foundation.org>
CC: Bjorn Helgaas <bhelg...@google.com>
CC: Vivek Goyal <vgo...@redhat.com>
Signed-off-by: Boaz Harrosh <b...@plexistor.com>
---
 arch/x86/kernel/e820.c | 3 +++
 include/linux/ioport.h | 1 +
 kernel/resource.c      | 9 ++++++++-
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 1a8a1c3..105bb37 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -961,6 +961,9 @@ void __init e820_reserve_resources(void)
 
                res->flags = IORESOURCE_MEM;
 
+               if (_is_unknown_type(e820.map[i].type))
+                       res->flags |= IORESOURCE_MEM_WARN;
+
                /*
                 * don't register the region that could be conflicted with
                 * pci device BAR resource and insert them later in
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 2c525022..f78972b 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -90,6 +90,7 @@ struct resource {
 #define IORESOURCE_MEM_32BIT           (3<<3)
 #define IORESOURCE_MEM_SHADOWABLE      (1<<5)  /* dup: IORESOURCE_SHADOWABLE */
 #define IORESOURCE_MEM_EXPANSIONROM    (1<<6)
+#define IORESOURCE_MEM_WARN            (1<<7)  /* WARN if requested by driver 
*/
 
 /* PnP I/O specific bits (IORESOURCE_BITS) */
 #define IORESOURCE_IO_16BIT_ADDR       (1<<0)
diff --git a/kernel/resource.c b/kernel/resource.c
index 19f2357..4bab16f 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -1075,8 +1075,15 @@ struct resource * __request_region(struct resource 
*parent,
                        break;
                if (conflict != parent) {
                        parent = conflict;
-                       if (!(conflict->flags & IORESOURCE_BUSY))
+                       if (!(conflict->flags & IORESOURCE_BUSY)) {
+                               if (unlikely(
+                                   (resource_type(conflict) == IORESOURCE_MEM)
+                                   && (conflict->flags & IORESOURCE_MEM_WARN)))
+                                       pr_warn("request region with unknown 
memory type [mem %#010llx-%#010llx] %s\n",
+                                               conflict->start, conflict->end,
+                                               conflict->name);
                                continue;
+                       }
                }
                if (conflict->flags & flags & IORESOURCE_MUXED) {
                        add_wait_queue(&muxed_resource_wait, &wait);
-- 
1.9.3

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