[3.16.y-ckt,stable] Patch "ACPI / PNP: Avoid conflicting resource reservations" has been added to staging queue

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 1b2d872c7398..bbde6af69584 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -165,11 +165,7 @@  static void __init acpi_request_region (struct acpi_generic_address *gas,
 	if (!addr || !length)
 		return;

-	/* Resources are never freed */
-	if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO)
-		request_region(addr, length, desc);
-	else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
-		request_mem_region(addr, length, desc);
+	acpi_reserve_region(addr, length, gas->space_id, 0, desc);
 }

 static void __init acpi_reserve_resources(void)
diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index 2ba8f02ced36..28314ba82320 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -26,6 +26,7 @@ 
 #include <linux/device.h>
 #include <linux/export.h>
 #include <linux/ioport.h>
+#include <linux/list.h>
 #include <linux/slab.h>

 #ifdef CONFIG_X86
@@ -538,3 +539,162 @@  int acpi_dev_get_resources(struct acpi_device *adev, struct list_head *list,
 	return c.count;
 }
 EXPORT_SYMBOL_GPL(acpi_dev_get_resources);
+
+struct reserved_region {
+	struct list_head node;
+	u64 start;
+	u64 end;
+};
+
+static LIST_HEAD(reserved_io_regions);
+static LIST_HEAD(reserved_mem_regions);
+
+static int request_range(u64 start, u64 end, u8 space_id, unsigned long flags,
+			 char *desc)
+{
+	unsigned int length = end - start + 1;
+	struct resource *res;
+
+	res = space_id == ACPI_ADR_SPACE_SYSTEM_IO ?
+		request_region(start, length, desc) :
+		request_mem_region(start, length, desc);
+	if (!res)
+		return -EIO;
+
+	res->flags &= ~flags;
+	return 0;
+}
+
+static int add_region_before(u64 start, u64 end, u8 space_id,
+			     unsigned long flags, char *desc,
+			     struct list_head *head)
+{
+	struct reserved_region *reg;
+	int error;
+
+	reg = kmalloc(sizeof(*reg), GFP_KERNEL);
+	if (!reg)
+		return -ENOMEM;
+
+	error = request_range(start, end, space_id, flags, desc);
+	if (error)
+		return error;
+
+	reg->start = start;
+	reg->end = end;
+	list_add_tail(&reg->node, head);
+	return 0;
+}
+
+/**
+ * acpi_reserve_region - Reserve an I/O or memory region as a system resource.
+ * @start: Starting address of the region.
+ * @length: Length of the region.
+ * @space_id: Identifier of address space to reserve the region from.
+ * @flags: Resource flags to clear for the region after requesting it.
+ * @desc: Region description (for messages).
+ *
+ * Reserve an I/O or memory region as a system resource to prevent others from
+ * using it.  If the new region overlaps with one of the regions (in the given
+ * address space) already reserved by this routine, only the non-overlapping
+ * parts of it will be reserved.
+ *
+ * Returned is either 0 (success) or a negative error code indicating a resource
+ * reservation problem.  It is the code of the first encountered error, but the
+ * routine doesn't abort until it has attempted to request all of the parts of
+ * the new region that don't overlap with other regions reserved previously.
+ *
+ * The resources requested by this routine are never released.
+ */
+int acpi_reserve_region(u64 start, unsigned int length, u8 space_id,
+			unsigned long flags, char *desc)
+{
+	struct list_head *regions;
+	struct reserved_region *reg;
+	u64 end = start + length - 1;
+	int ret = 0, error = 0;
+
+	if (space_id == ACPI_ADR_SPACE_SYSTEM_IO)
+		regions = &reserved_io_regions;
+	else if (space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+		regions = &reserved_mem_regions;
+	else
+		return -EINVAL;
+
+	if (list_empty(regions))
+		return add_region_before(start, end, space_id, flags, desc, regions);
+
+	list_for_each_entry(reg, regions, node)
+		if (reg->start == end + 1) {
+			/* The new region can be prepended to this one. */
+			ret = request_range(start, end, space_id, flags, desc);
+			if (!ret)
+				reg->start = start;
+
+			return ret;
+		} else if (reg->start > end) {
+			/* No overlap.  Add the new region here and get out. */
+			return add_region_before(start, end, space_id, flags,
+						 desc, &reg->node);
+		} else if (reg->end == start - 1) {
+			goto combine;
+		} else if (reg->end >= start) {
+			goto overlap;
+		}
+
+	/* The new region goes after the last existing one. */
+	return add_region_before(start, end, space_id, flags, desc, regions);
+
+ overlap:
+	/*
+	 * The new region overlaps an existing one.
+	 *
+	 * The head part of the new region immediately preceding the existing
+	 * overlapping one can be combined with it right away.
+	 */
+	if (reg->start > start) {
+		error = request_range(start, reg->start - 1, space_id, flags, desc);
+		if (error)
+			ret = error;
+		else
+			reg->start = start;
+	}
+
+ combine:
+	/*
+	 * The new region is adjacent to an existing one.  If it extends beyond
+	 * that region all the way to the next one, it is possible to combine
+	 * all three of them.
+	 */
+	while (reg->end < end) {
+		struct reserved_region *next = NULL;
+		u64 a = reg->end + 1, b = end;
+
+		if (!list_is_last(&reg->node, regions)) {
+			next = list_next_entry(reg, node);
+			if (next->start <= end)
+				b = next->start - 1;
+		}
+		error = request_range(a, b, space_id, flags, desc);
+		if (!error) {
+			if (next && next->start == b + 1) {
+				reg->end = next->end;
+				list_del(&next->node);
+				kfree(next);
+			} else {
+				reg->end = end;
+				break;
+			}
+		} else if (next) {
+			if (!ret)
+				ret = error;
+
+			reg = next;
+		} else {
+			break;
+		}
+	}
+
+	return ret ? ret : error;
+}
+EXPORT_SYMBOL_GPL(acpi_reserve_region);
diff --git a/drivers/pnp/system.c b/drivers/pnp/system.c
index 49c1720df59a..515f33882ab8 100644
--- a/drivers/pnp/system.c
+++ b/drivers/pnp/system.c
@@ -7,6 +7,7 @@ 
  *	Bjorn Helgaas <bjorn.helgaas@hp.com>
  */

+#include <linux/acpi.h>
 #include <linux/pnp.h>
 #include <linux/device.h>
 #include <linux/init.h>
@@ -22,25 +23,41 @@  static const struct pnp_device_id pnp_dev_table[] = {
 	{"", 0}
 };

+#ifdef CONFIG_ACPI
+static bool __reserve_range(u64 start, unsigned int length, bool io, char *desc)
+{
+	u8 space_id = io ? ACPI_ADR_SPACE_SYSTEM_IO : ACPI_ADR_SPACE_SYSTEM_MEMORY;
+	return !acpi_reserve_region(start, length, space_id, IORESOURCE_BUSY, desc);
+}
+#else
+static bool __reserve_range(u64 start, unsigned int length, bool io, char *desc)
+{
+	struct resource *res;
+
+	res = io ? request_region(start, length, desc) :
+		request_mem_region(start, length, desc);
+	if (res) {
+		res->flags &= ~IORESOURCE_BUSY;
+		return true;
+	}
+	return false;
+}
+#endif
+
 static void reserve_range(struct pnp_dev *dev, struct resource *r, int port)
 {
 	char *regionid;
 	const char *pnpid = dev_name(&dev->dev);
 	resource_size_t start = r->start, end = r->end;
-	struct resource *res;
+	bool reserved;

 	regionid = kmalloc(16, GFP_KERNEL);
 	if (!regionid)
 		return;

 	snprintf(regionid, 16, "pnp %s", pnpid);
-	if (port)
-		res = request_region(start, end - start + 1, regionid);
-	else
-		res = request_mem_region(start, end - start + 1, regionid);
-	if (res)
-		res->flags &= ~IORESOURCE_BUSY;
-	else
+	reserved = __reserve_range(start, end - start + 1, !!port, regionid);
+	if (!reserved)
 		kfree(regionid);

 	/*
@@ -49,7 +66,7 @@  static void reserve_range(struct pnp_dev *dev, struct resource *r, int port)
 	 * have double reservations.
 	 */
 	dev_info(&dev->dev, "%pR %s reserved\n", r,
-		 res ? "has been" : "could not be");
+		 reserved ? "has been" : "could not be");
 }

 static void reserve_resources_of_dev(struct pnp_dev *dev)
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 358c01b971db..fa91beba3cd0 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -306,6 +306,9 @@  int acpi_check_region(resource_size_t start, resource_size_t n,

 int acpi_resources_are_enforced(void);

+int acpi_reserve_region(u64 start, unsigned int length, u8 space_id,
+			unsigned long flags, char *desc);
+
 #ifdef CONFIG_HIBERNATION
 void __init acpi_no_s4_hw_signature(void);
 #endif
@@ -468,6 +471,13 @@  static inline int acpi_check_region(resource_size_t start, resource_size_t n,
 	return 0;
 }

+static inline int acpi_reserve_region(u64 start, unsigned int length,
+				      u8 space_id, unsigned long flags,
+				      char *desc)
+{
+	return -ENXIO;
+}
+
 struct acpi_table_header;
 static inline int acpi_table_parse(char *id,
 				int (*handler)(struct acpi_table_header *))