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authorJoerg Roedel <joerg.roedel@amd.com>2009-06-02 14:45:02 (GMT)
committerJoerg Roedel <joerg.roedel@amd.com>2009-06-02 14:45:02 (GMT)
commitbdc2911cde7d18580a545483844d75fdb3551729 (patch)
tree53e6df89e8a0255f7fd749b33e27d76746edc687 /lib/dma-debug.c
parent88f3907f6f447899544beadf491dccb32015dacb (diff)
parent016ea6874a6d58df85b54f56997d26df13c307b2 (diff)
Merge branches 'dma-debug/fixes' and 'dma-debug/driver-filter' into dma-debug/2.6.31
Diffstat (limited to 'lib/dma-debug.c')
-rw-r--r--lib/dma-debug.c167
1 files changed, 166 insertions, 1 deletions
diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index 1abed17..f49ab22 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_all_errors_dent __read_mostly;
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" };
@@ -133,9 +145,48 @@ static inline void dump_entry_trace(struct dma_debug_entry *entry)
#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); \
@@ -412,6 +463,97 @@ out_err:
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);
@@ -455,6 +597,11 @@ static int dma_debug_fs_init(void)
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:
@@ -1044,3 +1191,21 @@ void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
}
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);

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