dma-buf/sw_sync: de-stage SW_SYNC

SW_SYNC allows to run tests on the sync_file framework via debugfs on

<debugfs>/sync/sw_sync

Opening and closing the file triggers creation and release of a sync
timeline. To create fences on this timeline the SW_SYNC_IOC_CREATE_FENCE
ioctl should be used. To increment the timeline value use SW_SYNC_IOC_INC.

Also it exports Sync information on

<debugfs>/sync/info

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 230 insertions, 0 deletions

diff --git a/drivers/dma-buf/sync_debug.c b/drivers/dma-buf/sync_debug.c
new file mode 100644
index 000000000000..fab95204cf74
--- /dev/null
+++ b/drivers/dma-buf/sync_debug.c
@@ -0,0 +1,230 @@
+/*
+ * Sync File validation framework and debug information
+ *
+ * Copyright (C) 2012 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/debugfs.h>
+#include "sync_debug.h"
+
+static struct dentry *dbgfs;
+
+static LIST_HEAD(sync_timeline_list_head);
+static DEFINE_SPINLOCK(sync_timeline_list_lock);
+static LIST_HEAD(sync_file_list_head);
+static DEFINE_SPINLOCK(sync_file_list_lock);
+
+void sync_timeline_debug_add(struct sync_timeline *obj)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&sync_timeline_list_lock, flags);
+	list_add_tail(&obj->sync_timeline_list, &sync_timeline_list_head);
+	spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
+}
+
+void sync_timeline_debug_remove(struct sync_timeline *obj)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&sync_timeline_list_lock, flags);
+	list_del(&obj->sync_timeline_list);
+	spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
+}
+
+void sync_file_debug_add(struct sync_file *sync_file)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&sync_file_list_lock, flags);
+	list_add_tail(&sync_file->sync_file_list, &sync_file_list_head);
+	spin_unlock_irqrestore(&sync_file_list_lock, flags);
+}
+
+void sync_file_debug_remove(struct sync_file *sync_file)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&sync_file_list_lock, flags);
+	list_del(&sync_file->sync_file_list);
+	spin_unlock_irqrestore(&sync_file_list_lock, flags);
+}
+
+static const char *sync_status_str(int status)
+{
+	if (status == 0)
+		return "signaled";
+
+	if (status > 0)
+		return "active";
+
+	return "error";
+}
+
+static void sync_print_fence(struct seq_file *s, struct fence *fence, bool show)
+{
+	int status = 1;
+	struct sync_timeline *parent = fence_parent(fence);
+
+	if (fence_is_signaled_locked(fence))
+		status = fence->status;
+
+	seq_printf(s, "  %s%sfence %s",
+		   show ? parent->name : "",
+		   show ? "_" : "",
+		   sync_status_str(status));
+
+	if (status <= 0) {
+		struct timespec64 ts64 =
+			ktime_to_timespec64(fence->timestamp);
+
+		seq_printf(s, "@%lld.%09ld", (s64)ts64.tv_sec, ts64.tv_nsec);
+	}
+
+	if (fence->ops->timeline_value_str &&
+		fence->ops->fence_value_str) {
+		char value[64];
+		bool success;
+
+		fence->ops->fence_value_str(fence, value, sizeof(value));
+		success = strlen(value);
+
+		if (success) {
+			seq_printf(s, ": %s", value);
+
+			fence->ops->timeline_value_str(fence, value,
+						       sizeof(value));
+
+			if (strlen(value))
+				seq_printf(s, " / %s", value);
+		}
+	}
+
+	seq_puts(s, "\n");
+}
+
+static void sync_print_obj(struct seq_file *s, struct sync_timeline *obj)
+{
+	struct list_head *pos;
+	unsigned long flags;
+
+	seq_printf(s, "%s: %d\n", obj->name, obj->value);
+
+	spin_lock_irqsave(&obj->child_list_lock, flags);
+	list_for_each(pos, &obj->child_list_head) {
+		struct sync_pt *pt =
+			container_of(pos, struct sync_pt, child_list);
+		sync_print_fence(s, &pt->base, false);
+	}
+	spin_unlock_irqrestore(&obj->child_list_lock, flags);
+}
+
+static void sync_print_sync_file(struct seq_file *s,
+				  struct sync_file *sync_file)
+{
+	int i;
+
+	seq_printf(s, "[%p] %s: %s\n", sync_file, sync_file->name,
+		   sync_status_str(atomic_read(&sync_file->status)));
+
+	for (i = 0; i < sync_file->num_fences; ++i)
+		sync_print_fence(s, sync_file->cbs[i].fence, true);
+}
+
+static int sync_debugfs_show(struct seq_file *s, void *unused)
+{
+	unsigned long flags;
+	struct list_head *pos;
+
+	seq_puts(s, "objs:\n--------------\n");
+
+	spin_lock_irqsave(&sync_timeline_list_lock, flags);
+	list_for_each(pos, &sync_timeline_list_head) {
+		struct sync_timeline *obj =
+			container_of(pos, struct sync_timeline,
+				     sync_timeline_list);
+
+		sync_print_obj(s, obj);
+		seq_puts(s, "\n");
+	}
+	spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
+
+	seq_puts(s, "fences:\n--------------\n");
+
+	spin_lock_irqsave(&sync_file_list_lock, flags);
+	list_for_each(pos, &sync_file_list_head) {
+		struct sync_file *sync_file =
+			container_of(pos, struct sync_file, sync_file_list);
+
+		sync_print_sync_file(s, sync_file);
+		seq_puts(s, "\n");
+	}
+	spin_unlock_irqrestore(&sync_file_list_lock, flags);
+	return 0;
+}
+
+static int sync_info_debugfs_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, sync_debugfs_show, inode->i_private);
+}
+
+static const struct file_operations sync_info_debugfs_fops = {
+	.open           = sync_info_debugfs_open,
+	.read           = seq_read,
+	.llseek         = seq_lseek,
+	.release        = single_release,
+};
+
+static __init int sync_debugfs_init(void)
+{
+	dbgfs = debugfs_create_dir("sync", NULL);
+
+	/*
+	 * The debugfs files won't ever get removed and thus, there is
+	 * no need to protect it against removal races. The use of
+	 * debugfs_create_file_unsafe() is actually safe here.
+	 */
+	debugfs_create_file_unsafe("info", 0444, dbgfs, NULL,
+				   &sync_info_debugfs_fops);
+	debugfs_create_file_unsafe("sw_sync", 0644, dbgfs, NULL,
+				   &sw_sync_debugfs_fops);
+
+	return 0;
+}
+late_initcall(sync_debugfs_init);
+
+#define DUMP_CHUNK 256
+static char sync_dump_buf[64 * 1024];
+void sync_dump(void)
+{
+	struct seq_file s = {
+		.buf = sync_dump_buf,
+		.size = sizeof(sync_dump_buf) - 1,
+	};
+	int i;
+
+	sync_debugfs_show(&s, NULL);
+
+	for (i = 0; i < s.count; i += DUMP_CHUNK) {
+		if ((s.count - i) > DUMP_CHUNK) {
+			char c = s.buf[i + DUMP_CHUNK];
+
+			s.buf[i + DUMP_CHUNK] = 0;
+			pr_cont("%s", s.buf + i);
+			s.buf[i + DUMP_CHUNK] = c;
+		} else {
+			s.buf[s.count] = 0;
+			pr_cont("%s", s.buf + i);
+		}
+	}
+}