resource: Add I/O resource descriptor

walk_iomem_res() and region_intersects() still need to use
strcmp() for searching a resource entry by @name in the iomem
table.

This patch introduces I/O resource descriptor 'desc' in struct
resource for the iomem search interfaces. Drivers can assign
their unique descriptor to a range when they support the search
interfaces.

Otherwise, 'desc' is set to IORES_DESC_NONE (0). This avoids
changing most of the drivers as they typically allocate resource
entries statically, or by calling alloc_resource(), kzalloc(),
or alloc_bootmem_low(), which set the field to zero by default.
A later patch will address some drivers that use kmalloc()
without zero'ing the field.

Also change release_mem_region_adjustable() to set 'desc' when
its resource entry gets separated. Other resource interfaces are
also changed to initialize 'desc' explicitly although
alloc_resource() sets it to 0.

Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jakub Sitnicki <jsitnicki@gmail.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm <linux-mm@kvack.org>
Link: http://lkml.kernel.org/r/1453841853-11383-4-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 18 insertions, 0 deletions

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 4b65d944717f..983bea05d69c 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -20,6 +20,7 @@ struct resource {
 	resource_size_t end;
 	const char *name;
 	unsigned long flags;
+	unsigned long desc;
 	struct resource *parent, *sibling, *child;
 };
 
@@ -112,6 +113,22 @@ struct resource {
 /* PCI control bits.  Shares IORESOURCE_BITS with above PCI ROM.  */
 #define IORESOURCE_PCI_FIXED		(1<<4)	/* Do not move resource */
 
+/*
+ * I/O Resource Descriptors
+ *
+ * Descriptors are used by walk_iomem_res_desc() and region_intersects()
+ * for searching a specific resource range in the iomem table.  Assign
+ * a new descriptor when a resource range supports the search interfaces.
+ * Otherwise, resource.desc must be set to IORES_DESC_NONE (0).
+ */
+enum {
+	IORES_DESC_NONE				= 0,
+	IORES_DESC_CRASH_KERNEL			= 1,
+	IORES_DESC_ACPI_TABLES			= 2,
+	IORES_DESC_ACPI_NV_STORAGE		= 3,
+	IORES_DESC_PERSISTENT_MEMORY		= 4,
+	IORES_DESC_PERSISTENT_MEMORY_LEGACY	= 5,
+};
 
 /* helpers to define resources */
 #define DEFINE_RES_NAMED(_start, _size, _name, _flags)			\
@@ -120,6 +137,7 @@ struct resource {
 		.end = (_start) + (_size) - 1,				\
 		.name = (_name),					\
 		.flags = (_flags),					\
+		.desc = IORES_DESC_NONE,				\
 	}
 
 #define DEFINE_RES_IO_NAMED(_start, _size, _name)			\