dmaengine: add a release for dma class devices and dependent infrastructure
Resolves:
WARNING: at drivers/base/core.c:122 device_release+0x4d/0x52()
Device 'dma0chan0' does not have a release() function, it is broken and must be fixed.
The dma_chan_dev object is introduced to gear-match sysfs kobject and
dmaengine channel lifetimes. When a channel is removed access to the
sysfs entries return -ENODEV until the kobject can be released.
The bulk of the change is updates to existing code to handle the extra
layer of indirection between a dma_chan and its struct device.
Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Cc: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index cdc8ecf..93c4c9a 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -64,36 +64,75 @@
/* --- sysfs implementation --- */
+/**
+ * dev_to_dma_chan - convert a device pointer to the its sysfs container object
+ * @dev - device node
+ *
+ * Must be called under dma_list_mutex
+ */
+static struct dma_chan *dev_to_dma_chan(struct device *dev)
+{
+ struct dma_chan_dev *chan_dev;
+
+ chan_dev = container_of(dev, typeof(*chan_dev), device);
+ return chan_dev->chan;
+}
+
static ssize_t show_memcpy_count(struct device *dev, struct device_attribute *attr, char *buf)
{
- struct dma_chan *chan = to_dma_chan(dev);
+ struct dma_chan *chan;
unsigned long count = 0;
int i;
+ int err;
- for_each_possible_cpu(i)
- count += per_cpu_ptr(chan->local, i)->memcpy_count;
+ mutex_lock(&dma_list_mutex);
+ chan = dev_to_dma_chan(dev);
+ if (chan) {
+ for_each_possible_cpu(i)
+ count += per_cpu_ptr(chan->local, i)->memcpy_count;
+ err = sprintf(buf, "%lu\n", count);
+ } else
+ err = -ENODEV;
+ mutex_unlock(&dma_list_mutex);
- return sprintf(buf, "%lu\n", count);
+ return err;
}
static ssize_t show_bytes_transferred(struct device *dev, struct device_attribute *attr,
char *buf)
{
- struct dma_chan *chan = to_dma_chan(dev);
+ struct dma_chan *chan;
unsigned long count = 0;
int i;
+ int err;
- for_each_possible_cpu(i)
- count += per_cpu_ptr(chan->local, i)->bytes_transferred;
+ mutex_lock(&dma_list_mutex);
+ chan = dev_to_dma_chan(dev);
+ if (chan) {
+ for_each_possible_cpu(i)
+ count += per_cpu_ptr(chan->local, i)->bytes_transferred;
+ err = sprintf(buf, "%lu\n", count);
+ } else
+ err = -ENODEV;
+ mutex_unlock(&dma_list_mutex);
- return sprintf(buf, "%lu\n", count);
+ return err;
}
static ssize_t show_in_use(struct device *dev, struct device_attribute *attr, char *buf)
{
- struct dma_chan *chan = to_dma_chan(dev);
+ struct dma_chan *chan;
+ int err;
- return sprintf(buf, "%d\n", chan->client_count);
+ mutex_lock(&dma_list_mutex);
+ chan = dev_to_dma_chan(dev);
+ if (chan)
+ err = sprintf(buf, "%d\n", chan->client_count);
+ else
+ err = -ENODEV;
+ mutex_unlock(&dma_list_mutex);
+
+ return err;
}
static struct device_attribute dma_attrs[] = {
@@ -103,9 +142,18 @@
__ATTR_NULL
};
+static void chan_dev_release(struct device *dev)
+{
+ struct dma_chan_dev *chan_dev;
+
+ chan_dev = container_of(dev, typeof(*chan_dev), device);
+ kfree(chan_dev);
+}
+
static struct class dma_devclass = {
.name = "dma",
.dev_attrs = dma_attrs,
+ .dev_release = chan_dev_release,
};
/* --- client and device registration --- */
@@ -420,7 +468,7 @@
list_for_each_entry(chan, &dev->channels, device_node) {
if (chan->client_count) {
pr_debug("%s: %s busy\n",
- __func__, dev_name(&chan->dev));
+ __func__, dma_chan_name(chan));
continue;
}
ret = chan;
@@ -466,22 +514,22 @@
if (err == -ENODEV) {
pr_debug("%s: %s module removed\n", __func__,
- dev_name(&chan->dev));
+ dma_chan_name(chan));
list_del_rcu(&device->global_node);
} else if (err)
pr_err("dmaengine: failed to get %s: (%d)\n",
- dev_name(&chan->dev), err);
+ dma_chan_name(chan), err);
else
break;
} else
pr_debug("%s: %s filter said false\n",
- __func__, dev_name(&chan->dev));
+ __func__, dma_chan_name(chan));
chan = NULL;
}
mutex_unlock(&dma_list_mutex);
pr_debug("%s: %s (%s)\n", __func__, chan ? "success" : "fail",
- chan ? dev_name(&chan->dev) : NULL);
+ chan ? dma_chan_name(chan) : NULL);
return chan;
}
@@ -521,7 +569,7 @@
break;
} else if (err)
pr_err("dmaengine: failed to get %s: (%d)\n",
- dev_name(&chan->dev), err);
+ dma_chan_name(chan), err);
}
}
@@ -601,14 +649,20 @@
chan->local = alloc_percpu(typeof(*chan->local));
if (chan->local == NULL)
continue;
+ chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
+ if (chan->dev == NULL) {
+ free_percpu(chan->local);
+ continue;
+ }
chan->chan_id = chancnt++;
- chan->dev.class = &dma_devclass;
- chan->dev.parent = device->dev;
- dev_set_name(&chan->dev, "dma%dchan%d",
+ chan->dev->device.class = &dma_devclass;
+ chan->dev->device.parent = device->dev;
+ chan->dev->chan = chan;
+ dev_set_name(&chan->dev->device, "dma%dchan%d",
device->dev_id, chan->chan_id);
- rc = device_register(&chan->dev);
+ rc = device_register(&chan->dev->device);
if (rc) {
free_percpu(chan->local);
chan->local = NULL;
@@ -645,7 +699,10 @@
list_for_each_entry(chan, &device->channels, device_node) {
if (chan->local == NULL)
continue;
- device_unregister(&chan->dev);
+ mutex_lock(&dma_list_mutex);
+ chan->dev->chan = NULL;
+ mutex_unlock(&dma_list_mutex);
+ device_unregister(&chan->dev->device);
free_percpu(chan->local);
}
return rc;
@@ -672,7 +729,10 @@
WARN_ONCE(chan->client_count,
"%s called while %d clients hold a reference\n",
__func__, chan->client_count);
- device_unregister(&chan->dev);
+ mutex_lock(&dma_list_mutex);
+ chan->dev->chan = NULL;
+ mutex_unlock(&dma_list_mutex);
+ device_unregister(&chan->dev->device);
}
}
EXPORT_SYMBOL(dma_async_device_unregister);
@@ -845,7 +905,7 @@
return DMA_SUCCESS;
WARN_ONCE(tx->parent, "%s: speculatively walking dependency chain for"
- " %s\n", __func__, dev_name(&tx->chan->dev));
+ " %s\n", __func__, dma_chan_name(tx->chan));
/* poll through the dependency chain, return when tx is complete */
do {