Merge branch 'dma-debug/2.6.31' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux-2.6-iommu into core/iommu
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index d9aa43d..25fb8bc 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -704,12 +704,24 @@
The current number of free dma_debug_entries
in the allocator.
+ dma-api/driver-filter
+ You can write a name of a driver into this file
+ to limit the debug output to requests from that
+ particular driver. Write an empty string to
+ that file to disable the filter and see
+ all errors again.
+
If you have this code compiled into your kernel it will be enabled by default.
If you want to boot without the bookkeeping anyway you can provide
'dma_debug=off' as a boot parameter. This will disable DMA-API debugging.
Notice that you can not enable it again at runtime. You have to reboot to do
so.
+If you want to see debug messages only for a special device driver you can
+specify the dma_debug_driver=<drivername> parameter. This will enable the
+driver filter at boot time. The debug code will only print errors for that
+driver afterwards. This filter can be disabled or changed later using debugfs.
+
When the code disables itself at runtime this is most likely because it ran
out of dma_debug_entries. These entries are preallocated at boot. The number
of preallocated entries is defined per architecture. If it is too low for you
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index e2999cb..8f9e17c 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -641,6 +641,13 @@
DMA-API debugging code disables itself because the
architectural default is too low.
+ dma_debug_driver=<driver_name>
+ With this option the DMA-API debugging driver
+ filter feature can be enabled at boot time. Just
+ pass the driver to filter for as the parameter.
+ The filter can be disabled or changed to another
+ driver later using sysfs.
+
dscc4.setup= [NET]
dtc3181e= [HW,SCSI]
diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index 8fcc09c..77053d9 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -23,9 +23,11 @@
#include <linux/dma-debug.h>
#include <linux/spinlock.h>
#include <linux/debugfs.h>
+#include <linux/uaccess.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/sched.h>
+#include <linux/ctype.h>
#include <linux/list.h>
#include <linux/slab.h>
@@ -98,6 +100,16 @@
static struct dentry *show_num_errors_dent __read_mostly;
static struct dentry *num_free_entries_dent __read_mostly;
static struct dentry *min_free_entries_dent __read_mostly;
+static struct dentry *filter_dent __read_mostly;
+
+/* per-driver filter related state */
+
+#define NAME_MAX_LEN 64
+
+static char current_driver_name[NAME_MAX_LEN] __read_mostly;
+static struct device_driver *current_driver __read_mostly;
+
+static DEFINE_RWLOCK(driver_name_lock);
static const char *type2name[4] = { "single", "page",
"scather-gather", "coherent" };
@@ -105,6 +117,11 @@
static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
"DMA_FROM_DEVICE", "DMA_NONE" };
+/* little merge helper - remove it after the merge window */
+#ifndef BUS_NOTIFY_UNBOUND_DRIVER
+#define BUS_NOTIFY_UNBOUND_DRIVER 0x0005
+#endif
+
/*
* The access to some variables in this macro is racy. We can't use atomic_t
* here because all these variables are exported to debugfs. Some of them even
@@ -128,9 +145,48 @@
#endif
}
+static bool driver_filter(struct device *dev)
+{
+ /* driver filter off */
+ if (likely(!current_driver_name[0]))
+ return true;
+
+ /* driver filter on and initialized */
+ if (current_driver && dev->driver == current_driver)
+ return true;
+
+ /* driver filter on but not yet initialized */
+ if (!current_driver && current_driver_name[0]) {
+ struct device_driver *drv = get_driver(dev->driver);
+ unsigned long flags;
+ bool ret = false;
+
+ if (!drv)
+ return false;
+
+ /* lock to protect against change of current_driver_name */
+ read_lock_irqsave(&driver_name_lock, flags);
+
+ if (drv->name &&
+ strncmp(current_driver_name, drv->name,
+ NAME_MAX_LEN-1) == 0) {
+ current_driver = drv;
+ ret = true;
+ }
+
+ read_unlock_irqrestore(&driver_name_lock, flags);
+ put_driver(drv);
+
+ return ret;
+ }
+
+ return false;
+}
+
#define err_printk(dev, entry, format, arg...) do { \
error_count += 1; \
- if (show_all_errors || show_num_errors > 0) { \
+ if (driver_filter(dev) && \
+ (show_all_errors || show_num_errors > 0)) { \
WARN(1, "%s %s: " format, \
dev_driver_string(dev), \
dev_name(dev) , ## arg); \
@@ -442,6 +498,97 @@
return -ENOMEM;
}
+static ssize_t filter_read(struct file *file, char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ unsigned long flags;
+ char buf[NAME_MAX_LEN + 1];
+ int len;
+
+ if (!current_driver_name[0])
+ return 0;
+
+ /*
+ * We can't copy to userspace directly because current_driver_name can
+ * only be read under the driver_name_lock with irqs disabled. So
+ * create a temporary copy first.
+ */
+ read_lock_irqsave(&driver_name_lock, flags);
+ len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
+ read_unlock_irqrestore(&driver_name_lock, flags);
+
+ return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static ssize_t filter_write(struct file *file, const char __user *userbuf,
+ size_t count, loff_t *ppos)
+{
+ unsigned long flags;
+ char buf[NAME_MAX_LEN];
+ size_t len = NAME_MAX_LEN - 1;
+ int i;
+
+ /*
+ * We can't copy from userspace directly. Access to
+ * current_driver_name is protected with a write_lock with irqs
+ * disabled. Since copy_from_user can fault and may sleep we
+ * need to copy to temporary buffer first
+ */
+ len = min(count, len);
+ if (copy_from_user(buf, userbuf, len))
+ return -EFAULT;
+
+ buf[len] = 0;
+
+ write_lock_irqsave(&driver_name_lock, flags);
+
+ /* Now handle the string we got from userspace very carefully.
+ * The rules are:
+ * - only use the first token we got
+ * - token delimiter is everything looking like a space
+ * character (' ', '\n', '\t' ...)
+ *
+ */
+ if (!isalnum(buf[0])) {
+ /*
+ If the first character userspace gave us is not
+ * alphanumerical then assume the filter should be
+ * switched off.
+ */
+ if (current_driver_name[0])
+ printk(KERN_INFO "DMA-API: switching off dma-debug "
+ "driver filter\n");
+ current_driver_name[0] = 0;
+ current_driver = NULL;
+ goto out_unlock;
+ }
+
+ /*
+ * Now parse out the first token and use it as the name for the
+ * driver to filter for.
+ */
+ for (i = 0; i < NAME_MAX_LEN; ++i) {
+ current_driver_name[i] = buf[i];
+ if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
+ break;
+ }
+ current_driver_name[i] = 0;
+ current_driver = NULL;
+
+ printk(KERN_INFO "DMA-API: enable driver filter for driver [%s]\n",
+ current_driver_name);
+
+out_unlock:
+ write_unlock_irqrestore(&driver_name_lock, flags);
+
+ return count;
+}
+
+const struct file_operations filter_fops = {
+ .read = filter_read,
+ .write = filter_write,
+};
+
static int dma_debug_fs_init(void)
{
dma_debug_dent = debugfs_create_dir("dma-api", NULL);
@@ -485,6 +632,11 @@
if (!min_free_entries_dent)
goto out_err;
+ filter_dent = debugfs_create_file("driver_filter", 0644,
+ dma_debug_dent, NULL, &filter_fops);
+ if (!filter_dent)
+ goto out_err;
+
return 0;
out_err:
@@ -493,9 +645,60 @@
return -ENOMEM;
}
+static int device_dma_allocations(struct device *dev)
+{
+ struct dma_debug_entry *entry;
+ unsigned long flags;
+ int count = 0, i;
+
+ for (i = 0; i < HASH_SIZE; ++i) {
+ spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
+ list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
+ if (entry->dev == dev)
+ count += 1;
+ }
+ spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
+ }
+
+ return count;
+}
+
+static int dma_debug_device_change(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct device *dev = data;
+ int count;
+
+
+ switch (action) {
+ case BUS_NOTIFY_UNBOUND_DRIVER:
+ count = device_dma_allocations(dev);
+ if (count == 0)
+ break;
+ err_printk(dev, NULL, "DMA-API: device driver has pending "
+ "DMA allocations while released from device "
+ "[count=%d]\n", count);
+ break;
+ default:
+ break;
+ }
+
+ return 0;
+}
+
void dma_debug_add_bus(struct bus_type *bus)
{
- /* FIXME: register notifier */
+ struct notifier_block *nb;
+
+ nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
+ if (nb == NULL) {
+ printk(KERN_ERR "dma_debug_add_bus: out of memory\n");
+ return;
+ }
+
+ nb->notifier_call = dma_debug_device_change;
+
+ bus_register_notifier(bus, nb);
}
/*
@@ -818,15 +1021,15 @@
entry->type = dma_debug_sg;
entry->dev = dev;
entry->paddr = sg_phys(s);
- entry->size = s->length;
- entry->dev_addr = s->dma_address;
+ entry->size = sg_dma_len(s);
+ entry->dev_addr = sg_dma_address(s);
entry->direction = direction;
entry->sg_call_ents = nents;
entry->sg_mapped_ents = mapped_ents;
if (!PageHighMem(sg_page(s))) {
check_for_stack(dev, sg_virt(s));
- check_for_illegal_area(dev, sg_virt(s), s->length);
+ check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
}
add_dma_entry(entry);
@@ -834,13 +1037,32 @@
}
EXPORT_SYMBOL(debug_dma_map_sg);
+static int get_nr_mapped_entries(struct device *dev, struct scatterlist *s)
+{
+ struct dma_debug_entry *entry;
+ struct hash_bucket *bucket;
+ unsigned long flags;
+ int mapped_ents = 0;
+ struct dma_debug_entry ref;
+
+ ref.dev = dev;
+ ref.dev_addr = sg_dma_address(s);
+ ref.size = sg_dma_len(s),
+
+ bucket = get_hash_bucket(&ref, &flags);
+ entry = hash_bucket_find(bucket, &ref);
+ if (entry)
+ mapped_ents = entry->sg_mapped_ents;
+ put_hash_bucket(bucket, &flags);
+
+ return mapped_ents;
+}
+
void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
int nelems, int dir)
{
- struct dma_debug_entry *entry;
struct scatterlist *s;
int mapped_ents = 0, i;
- unsigned long flags;
if (unlikely(global_disable))
return;
@@ -851,8 +1073,8 @@
.type = dma_debug_sg,
.dev = dev,
.paddr = sg_phys(s),
- .dev_addr = s->dma_address,
- .size = s->length,
+ .dev_addr = sg_dma_address(s),
+ .size = sg_dma_len(s),
.direction = dir,
.sg_call_ents = 0,
};
@@ -860,14 +1082,9 @@
if (mapped_ents && i >= mapped_ents)
break;
- if (mapped_ents == 0) {
- struct hash_bucket *bucket;
+ if (!i) {
ref.sg_call_ents = nelems;
- bucket = get_hash_bucket(&ref, &flags);
- entry = hash_bucket_find(bucket, &ref);
- if (entry)
- mapped_ents = entry->sg_mapped_ents;
- put_hash_bucket(bucket, &flags);
+ mapped_ents = get_nr_mapped_entries(dev, s);
}
check_unmap(&ref);
@@ -969,14 +1186,20 @@
int nelems, int direction)
{
struct scatterlist *s;
- int i;
+ int mapped_ents = 0, i;
if (unlikely(global_disable))
return;
for_each_sg(sg, s, nelems, i) {
- check_sync(dev, s->dma_address, s->dma_length, 0,
- direction, true);
+ if (!i)
+ mapped_ents = get_nr_mapped_entries(dev, s);
+
+ if (i >= mapped_ents)
+ break;
+
+ check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
+ direction, true);
}
}
EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
@@ -985,15 +1208,39 @@
int nelems, int direction)
{
struct scatterlist *s;
- int i;
+ int mapped_ents = 0, i;
if (unlikely(global_disable))
return;
for_each_sg(sg, s, nelems, i) {
- check_sync(dev, s->dma_address, s->dma_length, 0,
- direction, false);
+ if (!i)
+ mapped_ents = get_nr_mapped_entries(dev, s);
+
+ if (i >= mapped_ents)
+ break;
+
+ check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
+ direction, false);
}
}
EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
+static int __init dma_debug_driver_setup(char *str)
+{
+ int i;
+
+ for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
+ current_driver_name[i] = *str;
+ if (*str == 0)
+ break;
+ }
+
+ if (current_driver_name[0])
+ printk(KERN_INFO "DMA-API: enable driver filter for "
+ "driver [%s]\n", current_driver_name);
+
+
+ return 1;
+}
+__setup("dma_debug_driver=", dma_debug_driver_setup);