From 41d5e59c1299f27983977bcfe3b360600996051c Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Tue, 6 Jan 2009 11:38:21 -0700 Subject: 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 Acked-by: Stephen Hemminger Cc: Haavard Skinnemoen Signed-off-by: Dan Williams --- drivers/dma/dmaengine.c | 106 +++++++++++++++++++++++++++++++++++++----------- 1 file changed, 83 insertions(+), 23 deletions(-) (limited to 'drivers/dma/dmaengine.c') 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 @@ static long dmaengine_ref_count; /* --- 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 @@ static struct device_attribute dma_attrs[] = { __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 @@ static struct dma_chan *private_candidate(dma_cap_mask_t *mask, struct dma_devic 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 @@ struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, v 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 @@ void dmaengine_get(void) 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 @@ int dma_async_device_register(struct dma_device *device) 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 @@ err_out: 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 @@ void dma_async_device_unregister(struct dma_device *device) 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 @@ dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx) 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 { -- cgit v1.1