linux-kernel - [PATCH 2/2] pnp: add PNP resource range checking function

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Date:	Sat, 6 Jun 2009 09:36:24 +0300 (EEST)
From:	Pekka J Enberg <penberg@...helsinki.fi>
To:	akpm@...ux-foundation.org
cc:	linux-kernel@...r.kernel.org, apw@...onical.com,
	colin.king@...onical.com, tim.gardner@...onicalc.com,
	bjorn.helgaas@...com
Subject: [PATCH 2/2] pnp: add PNP resource range checking function

From: Bjorn Helgaas <bjorn.helgaas@...com>

Add a PNP resource range check function, indicating whether a resource
has been assigned to any device.

This patch fixes a serious performance regression on Asus Eee PC 701 (and
probably other) systems. See the following URL for details:

  http://bugs.launchpad.net/bugs/349314

[ apw@...onical.com: fixed up exports et al ]
Signed-off-by: Andy Whitcroft <apw@...onical.com>
Acked-by: Colin King <colin.king@...onical.com>
Acked-by: Tim Gardner <tim.gardner@...onicalc.com>
Signed-off-by: Pekka Enberg <penberg@...helsinki.fi>
---
Andrew, I am not completely sure if this is needed or not. But apparently 
the Ubuntu folks think it is and I did test the combination of these two 
patches.

 drivers/pnp/resource.c |   18 ++++++++++++++++++
 include/linux/pnp.h    |    2 ++
 2 files changed, 20 insertions(+), 0 deletions(-)

diff --git a/drivers/pnp/resource.c b/drivers/pnp/resource.c
index f604061..ba97654 100644
--- a/drivers/pnp/resource.c
+++ b/drivers/pnp/resource.c
@@ -638,6 +638,24 @@ int pnp_possible_config(struct pnp_dev *dev, int type, resource_size_t start,
 }
 EXPORT_SYMBOL(pnp_possible_config);
 
+int pnp_range_reserved(resource_size_t start, resource_size_t end)
+{
+	struct pnp_dev *dev;
+	struct pnp_resource *pnp_res;
+	resource_size_t *dev_start, *dev_end;
+
+	pnp_for_each_dev(dev) {
+		list_for_each_entry(pnp_res, &dev->resources, list) {
+			dev_start = &pnp_res->res.start;
+			dev_end   = &pnp_res->res.end;
+			if (ranged_conflict(&start, &end, dev_start, dev_end))
+				return 1;
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL(pnp_range_reserved);
+
 /* format is: pnp_reserve_irq=irq1[,irq2] .... */
 static int __init pnp_setup_reserve_irq(char *str)
 {
diff --git a/include/linux/pnp.h b/include/linux/pnp.h
index ca3c887..b063c73 100644
--- a/include/linux/pnp.h
+++ b/include/linux/pnp.h
@@ -446,6 +446,7 @@ int pnp_start_dev(struct pnp_dev *dev);
 int pnp_stop_dev(struct pnp_dev *dev);
 int pnp_activate_dev(struct pnp_dev *dev);
 int pnp_disable_dev(struct pnp_dev *dev);
+int pnp_range_reserved(resource_size_t start, resource_size_t end);
 
 /* protocol helpers */
 int pnp_is_active(struct pnp_dev *dev);
@@ -476,6 +477,7 @@ static inline int pnp_start_dev(struct pnp_dev *dev) { return -ENODEV; }
 static inline int pnp_stop_dev(struct pnp_dev *dev) { return -ENODEV; }
 static inline int pnp_activate_dev(struct pnp_dev *dev) { return -ENODEV; }
 static inline int pnp_disable_dev(struct pnp_dev *dev) { return -ENODEV; }
+static inline int pnp_range_reserved(resource_size_t start, resource_size_t end) { return 0;}
 
 /* protocol helpers */
 static inline int pnp_is_active(struct pnp_dev *dev) { return 0; }
-- 
1.5.6.3

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