1 files changed, 54 insertions, 15 deletions

diff --git a/kernel/relay.c b/kernel/relay.c
index c0c93a04d4ce..8d915fe98198 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -118,7 +118,7 @@ static void *relay_alloc_buf(struct rchan_buf *buf, size_t *size)
 		return NULL;
 
 	for (i = 0; i < n_pages; i++) {
-		buf->page_array[i] = alloc_page(GFP_KERNEL);
+		buf->page_array[i] = alloc_page(GFP_KERNEL | __GFP_ZERO);
 		if (unlikely(!buf->page_array[i]))
 			goto depopulate;
 		set_page_private(buf->page_array[i], (unsigned long)buf);
@@ -127,7 +127,6 @@ static void *relay_alloc_buf(struct rchan_buf *buf, size_t *size)
 	if (!mem)
 		goto depopulate;
 
-	memset(mem, 0, *size);
 	buf->page_count = n_pages;
 	return mem;
 
@@ -250,13 +249,18 @@ EXPORT_SYMBOL_GPL(relay_buf_full);
  */
 
 static int relay_subbuf_start(struct rchan_buf *buf, void *subbuf,
-			      void *prev_subbuf, size_t prev_padding)
+			      void *prev_subbuf)
 {
+	int full = relay_buf_full(buf);
+
+	if (full)
+		buf->stats.full_count++;
+
 	if (!buf->chan->cb->subbuf_start)
-		return !relay_buf_full(buf);
+		return !full;
 
 	return buf->chan->cb->subbuf_start(buf, subbuf,
-					   prev_subbuf, prev_padding);
+					   prev_subbuf);
 }
 
 /**
@@ -298,11 +302,13 @@ static void __relay_reset(struct rchan_buf *buf, unsigned int init)
 	buf->finalized = 0;
 	buf->data = buf->start;
 	buf->offset = 0;
+	buf->stats.full_count = 0;
+	buf->stats.big_count = 0;
 
 	for (i = 0; i < buf->chan->n_subbufs; i++)
 		buf->padding[i] = 0;
 
-	relay_subbuf_start(buf, buf->data, NULL, 0);
+	relay_subbuf_start(buf, buf->data, NULL);
 }
 
 /**
@@ -555,9 +561,11 @@ size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length)
 		goto toobig;
 
 	if (buf->offset != buf->chan->subbuf_size + 1) {
-		buf->prev_padding = buf->chan->subbuf_size - buf->offset;
+		size_t prev_padding;
+
+		prev_padding = buf->chan->subbuf_size - buf->offset;
 		old_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
-		buf->padding[old_subbuf] = buf->prev_padding;
+		buf->padding[old_subbuf] = prev_padding;
 		buf->subbufs_produced++;
 		if (buf->dentry)
 			d_inode(buf->dentry)->i_size +=
@@ -582,7 +590,7 @@ size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length)
 	new_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
 	new = buf->start + new_subbuf * buf->chan->subbuf_size;
 	buf->offset = 0;
-	if (!relay_subbuf_start(buf, new, old, buf->prev_padding)) {
+	if (!relay_subbuf_start(buf, new, old)) {
 		buf->offset = buf->chan->subbuf_size + 1;
 		return 0;
 	}
@@ -595,7 +603,7 @@ size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length)
 	return length;
 
 toobig:
-	buf->chan->last_toobig = length;
+	buf->stats.big_count++;
 	return 0;
 }
 EXPORT_SYMBOL_GPL(relay_switch_subbuf);
@@ -655,11 +663,6 @@ void relay_close(struct rchan *chan)
 			if ((buf = *per_cpu_ptr(chan->buf, i)))
 				relay_close_buf(buf);
 
-	if (chan->last_toobig)
-		printk(KERN_WARNING "relay: one or more items not logged "
-		       "[item size (%zd) > sub-buffer size (%zd)]\n",
-		       chan->last_toobig, chan->subbuf_size);
-
 	list_del(&chan->list);
 	kref_put(&chan->kref, relay_destroy_channel);
 	mutex_unlock(&relay_channels_mutex);
@@ -694,6 +697,42 @@ void relay_flush(struct rchan *chan)
 EXPORT_SYMBOL_GPL(relay_flush);
 
 /**
+ *	relay_stats - get channel buffer statistics
+ *	@chan: the channel
+ *	@flags: select particular information to get
+ *
+ *	Returns the count of certain field that caller specifies.
+ */
+size_t relay_stats(struct rchan *chan, int flags)
+{
+	unsigned int i, count = 0;
+	struct rchan_buf *rbuf;
+
+	if (!chan || flags > RELAY_STATS_LAST)
+		return 0;
+
+	if (chan->is_global) {
+		rbuf = *per_cpu_ptr(chan->buf, 0);
+		if (flags & RELAY_STATS_BUF_FULL)
+			count = rbuf->stats.full_count;
+		else if (flags & RELAY_STATS_WRT_BIG)
+			count = rbuf->stats.big_count;
+	} else {
+		for_each_online_cpu(i) {
+			rbuf = *per_cpu_ptr(chan->buf, i);
+			if (rbuf) {
+				if (flags & RELAY_STATS_BUF_FULL)
+					count += rbuf->stats.full_count;
+				else if (flags & RELAY_STATS_WRT_BIG)
+					count += rbuf->stats.big_count;
+			}
+		}
+	}
+
+	return count;
+}
+
+/**
  *	relay_file_open - open file op for relay files
  *	@inode: the inode
  *	@filp: the file