[RFC 4/9] android/sync: Improved debug dump to dmesg

[John.C.Harrison@Intel.com]

From: John Harrison <John.C.Harrison@Intel.com>

The sync code has a facility for dumping current state information via
debugfs. It also has a way to re-use the same code for dumping to the
kernel log on an internal error. However, the redirection was rather
clunky and split the output across multiple prints at arbitrary
boundaries. This made it difficult to read and could result in output
from different sources being randomly interspersed.

This patch improves the redirection code to split the output on line
feed boundaries instead. It also adds support for highlighting the
offending fence object that caused the state dump in the first place.

v0.4: New patch in series.

v0.5: Twiddled white space and line wrapping to keep style checker
happy.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Cc: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Riley Andrews <riandrews@android.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
---
 drivers/android/sync.c       |  9 ++++++--
 drivers/android/sync.h       |  5 +++--
 drivers/android/sync_debug.c | 51 +++++++++++++++++++++++++++++++++-----------
 3 files changed, 48 insertions(+), 17 deletions(-)

diff --git a/drivers/android/sync.c b/drivers/android/sync.c
index 7f0e919..db4a54b 100644
--- a/drivers/android/sync.c
+++ b/drivers/android/sync.c
@@ -86,6 +86,11 @@ static void sync_timeline_put(struct sync_timeline *obj)
 
 void sync_timeline_destroy(struct sync_timeline *obj)
 {
+	if (!list_empty(&obj->active_list_head)) {
+		pr_info("destroying timeline with outstanding fences!\n");
+		sync_dump_timeline(obj);
+	}
+
 	obj->destroyed = true;
 	/*
 	 * Ensure timeline is marked as destroyed before
@@ -397,7 +402,7 @@ int sync_fence_wait(struct sync_fence *fence, long timeout)
 		if (timeout) {
 			pr_info("fence timeout on [%p] after %dms\n", fence,
 				jiffies_to_msecs(timeout));
-			sync_dump();
+			sync_dump(fence);
 		}
 		return -ETIME;
 	}
@@ -405,7 +410,7 @@ int sync_fence_wait(struct sync_fence *fence, long timeout)
 	ret = atomic_read(&fence->status);
 	if (ret) {
 		pr_info("fence error %ld on [%p]\n", ret, fence);
-		sync_dump();
+		sync_dump(fence);
 	}
 	return ret;
 }
diff --git a/drivers/android/sync.h b/drivers/android/sync.h
index 4ccff01..d57fa0a 100644
--- a/drivers/android/sync.h
+++ b/drivers/android/sync.h
@@ -351,14 +351,15 @@ void sync_timeline_debug_add(struct sync_timeline *obj);
 void sync_timeline_debug_remove(struct sync_timeline *obj);
 void sync_fence_debug_add(struct sync_fence *fence);
 void sync_fence_debug_remove(struct sync_fence *fence);
-void sync_dump(void);
+void sync_dump(struct sync_fence *fence);
+void sync_dump_timeline(struct sync_timeline *timeline);
 
 #else
 # define sync_timeline_debug_add(obj)
 # define sync_timeline_debug_remove(obj)
 # define sync_fence_debug_add(fence)
 # define sync_fence_debug_remove(fence)
-# define sync_dump()
+# define sync_dump(fence)
 #endif
 int sync_fence_wake_up_wq(wait_queue_t *curr, unsigned mode,
 				 int wake_flags, void *key);
diff --git a/drivers/android/sync_debug.c b/drivers/android/sync_debug.c
index 02a1649..4a2f9f5 100644
--- a/drivers/android/sync_debug.c
+++ b/drivers/android/sync_debug.c
@@ -228,28 +228,53 @@ late_initcall(sync_debugfs_init);
 
 #define DUMP_CHUNK 256
 static char sync_dump_buf[64 * 1024];
-void sync_dump(void)
+
+static void sync_dump_dfs(struct seq_file *s, void *targetPtr)
+{
+	char *start, *end;
+	char targetStr[100];
+
+	if (targetPtr)
+		snprintf(targetStr, sizeof(targetStr) - 1, "%p", targetPtr);
+
+	start = end = s->buf;
+	while ((end = strchr(end, '\n'))) {
+		*end = 0;
+		if (targetPtr && strstr(start, targetStr))
+			pr_info("*** %s ***\n", start);
+		else
+			pr_info("%s\n", start);
+		start = ++end;
+	}
+
+	if ((start - s->buf) < s->count)
+		pr_info("%d vs %d: >?>%s<?<\n", (uint32_t) (start - s->buf),
+			(uint32_t) s->count, start);
+}
+
+void sync_dump(struct sync_fence *targetPtr)
 {
 	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];
+	sync_dump_dfs(&s, targetPtr);
+}
 
-			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);
-		}
-	}
+void sync_dump_timeline(struct sync_timeline *timeline)
+{
+	struct seq_file s = {
+		.buf = sync_dump_buf,
+		.size = sizeof(sync_dump_buf) - 1,
+	};
+
+	pr_info("timeline: %p\n", timeline);
+	sync_print_obj(&s, timeline);
+
+	sync_dump_dfs(&s, NULL);
 }
 
 #endif
-- 
1.9.1

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