[PATCH v3 03/17] resource: Add I/O resource descriptor

From: Toshi Kani
Date: Tue Jan 05 2016 - 14:00:29 EST


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 resoruce, for the iomem search interfaces. Drivers
can assign their unique descritor 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.

Link: http://lkml.kernel.org/r/<20151216181712.GJ29775@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Toshi Kani <toshi.kani@xxxxxxx>
---
include/linux/ioport.h | 18 ++++++++++++++++++
kernel/resource.c | 5 +++++
2 files changed, 23 insertions(+)

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 4b65d94..983bea0 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) \
diff --git a/kernel/resource.c b/kernel/resource.c
index d30a175..65eca4d 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -949,6 +949,7 @@ static void __init __reserve_region_with_split(struct resource *root,
res->start = start;
res->end = end;
res->flags = IORESOURCE_BUSY;
+ res->desc = IORES_DESC_NONE;

while (1) {

@@ -983,6 +984,7 @@ static void __init __reserve_region_with_split(struct resource *root,
next_res->start = conflict->end + 1;
next_res->end = end;
next_res->flags = IORESOURCE_BUSY;
+ next_res->desc = IORES_DESC_NONE;
}
} else {
res->start = conflict->end + 1;
@@ -1074,6 +1076,7 @@ struct resource * __request_region(struct resource *parent,
res->end = start + n - 1;
res->flags = resource_type(parent) | resource_ext_type(parent);
res->flags |= IORESOURCE_BUSY | flags;
+ res->desc = IORES_DESC_NONE;

write_lock(&resource_lock);

@@ -1238,6 +1241,7 @@ int release_mem_region_adjustable(struct resource *parent,
new_res->start = end + 1;
new_res->end = res->end;
new_res->flags = res->flags;
+ new_res->desc = res->desc;
new_res->parent = res->parent;
new_res->sibling = res->sibling;
new_res->child = NULL;
@@ -1413,6 +1417,7 @@ static int __init reserve_setup(char *str)
res->start = io_start;
res->end = io_start + io_num - 1;
res->flags = IORESOURCE_BUSY;
+ res->desc = IORES_DESC_NONE;
res->child = NULL;
if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
reserved = x+1;
--
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