[coreboot] New patch to review for coreboot: 5da88b0 Use dev_lock for alloc_find_dev()

[Kyösti Mälkki]

Kyösti Mälkki ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/1188

-gerrit

commit 5da88b005c2b1114d49ba345893f457f44353ff3
Author: Kyösti Mälkki 
Date:   Sat Jul 7 17:15:51 2012 +0300

Use dev_lock for alloc_find_dev()

If threads called alloc_find_dev() with same device_path
    simultaneously, two device nodes could be allocated.
    This bug is not triggered by current code.

Change-Id: Ifc87021c8d6f422901c5de5dd17392e3e2309afa
    Signed-off-by: Kyösti Mälkki 
---
 src/devices/device.c      |   30 +++++++++++++++++++++++++++---
 src/devices/device_util.c |   16 ----------------
 2 files changed, 27 insertions(+), 19 deletions(-)

diff --git a/src/devices/device.c b/src/devices/device.c
index ebac1a0..fafa599 100644
--- a/src/devices/device.c
+++ b/src/devices/device.c
@@ -66,12 +66,10 @@ DECLARE_SPIN_LOCK(dev_lock)
  *
  * @see device_path
  */
-device_t alloc_dev(struct bus *parent, struct device_path *path)
+static device_t __alloc_dev(struct bus *parent, struct device_path *path)
 {
    device_t dev, child;

-	spin_lock(&dev_lock);
-
    /* Find the last child of our parent. */
    for (child = parent->children; child && child->sibling; /* */ )
    	child = child->sibling;
@@ -99,11 +97,37 @@ device_t alloc_dev(struct bus *parent, struct device_path *path)
    last_dev->next = dev;
    last_dev = dev;

+	return dev;
+}
+
+device_t alloc_dev(struct bus *parent, struct device_path *path)
+{
+	device_t dev;
+	spin_lock(&dev_lock);
+	dev = __alloc_dev(parent, path);
    spin_unlock(&dev_lock);
    return dev;
 }

/**
+ * See if a device structure already exists and if not allocate it.
+ *
+ * @param parent The bus to find the device on.
+ * @param path The relative path from the bus to the appropriate device.
+ * @return Pointer to a device structure for the device on bus at path.
+ */
+device_t alloc_find_dev(struct bus *parent, struct device_path *path)
+{
+	device_t child;
+	spin_lock(&dev_lock);
+	child = find_dev_path(parent, path);
+	if (!child)
+		child = __alloc_dev(parent, path);
+	spin_unlock(&dev_lock);
+	return child;
+}
+
+/**
  * Round a number up to an alignment.
  *
  * @param val The starting value.
diff --git a/src/devices/device_util.c b/src/devices/device_util.c
index 5225938..ecc2c13 100644
--- a/src/devices/device_util.c
+++ b/src/devices/device_util.c
@@ -48,22 +48,6 @@ device_t find_dev_path(struct bus *parent, struct device_path *path)
 }

/**
- * See if a device structure already exists and if not allocate it.
- *
- * @param parent The bus to find the device on.
- * @param path The relative path from the bus to the appropriate device.
- * @return Pointer to a device structure for the device on bus at path.
- */
-device_t alloc_find_dev(struct bus *parent, struct device_path *path)
-{
-	device_t child;
-	child = find_dev_path(parent, path);
-	if (!child)
-		child = alloc_dev(parent, path);
-	return child;
-}
-
-/**
  * Given a PCI bus and a devfn number, find the device structure.
  *
  * @param bus The bus number.