--- linux-2.6.13-rc6-mm2/fs/relayfs/inode.c~	2005-08-23 14:29:11.000000000 +0200
+++ linux-2.6.13-rc6-mm2/fs/relayfs/inode.c	2005-08-23 14:29:54.000000000 +0200
@@ -302,94 +302,73 @@
  *	return the original value.
  */
 static inline size_t relayfs_read_start(size_t read_pos,
-					size_t avail,
-					size_t start_subbuf,
 					struct rchan_buf *buf)
 {
-	size_t read_subbuf, adj_read_subbuf;
-	size_t padding, padding_start, padding_end;
+	size_t read_subbuf, padding, padding_start, padding_end;
 	size_t subbuf_size = buf->chan->subbuf_size;
 	size_t n_subbufs = buf->chan->n_subbufs;
-
+	
 	read_subbuf = read_pos / subbuf_size;
-	adj_read_subbuf = (read_subbuf + start_subbuf) % n_subbufs;
-
-	if ((read_subbuf + 1) * subbuf_size <= avail) {
-		padding = buf->padding[adj_read_subbuf];
-		padding_start = (read_subbuf + 1) * subbuf_size - padding;
-		padding_end = (read_subbuf + 1) * subbuf_size;
-		if (read_pos >= padding_start && read_pos < padding_end) {
-			read_subbuf = (read_subbuf + 1) % n_subbufs;
-			read_pos = read_subbuf * subbuf_size;
-		}
+	padding = buf->padding[read_subbuf];
+	padding_start = (read_subbuf + 1) * subbuf_size - padding;
+	padding_end = (read_subbuf + 1) * subbuf_size;
+	if (read_pos >= padding_start && read_pos < padding_end) {
+		read_subbuf = (read_subbuf + 1) % n_subbufs;
+		read_pos = read_subbuf * subbuf_size;
 	}
 
 	return read_pos;
 }
 
 /**
- *	relayfs_read_end - return the end of available bytes to read
- *
- *	If the read_pos is in the middle of a full sub-buffer, return
- *	the padding-adjusted end of that sub-buffer, otherwise return
- *	the position after the last byte written to the buffer.  At
- *	most, 1 sub-buffer can be read at a time.
+ *	relayfs_read_avail - return total available along with buffer start
  *
+ *	Because buffers are circular, the 'beginning' of the buffer
+ *	depends on where the buffer was last written.  If the writer
+ *	has cycled around the buffer, the beginning is defined to be
+ *	the beginning of the sub-buffer following the last sub-buffer
+ *	written to, otherwise it's the beginning of sub-buffer 0.
+ *	
  */
-static inline size_t relayfs_read_end(size_t read_pos,
-				      size_t avail,
-				      size_t start_subbuf,
-				      struct rchan_buf *buf)
+static inline size_t relayfs_read_avail(size_t read_pos,
+					struct rchan_buf *buf)
 {
-	size_t padding, read_endpos, buf_offset;
-	size_t read_subbuf, adj_read_subbuf;
+	size_t padding, avail = 0;
+	size_t read_subbuf, read_offset, write_subbuf, write_offset;
 	size_t subbuf_size = buf->chan->subbuf_size;
-	size_t n_subbufs = buf->chan->n_subbufs;
 
-	buf_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
+	write_subbuf = (buf->data - buf->start) / subbuf_size;
+	write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
 	read_subbuf = read_pos / subbuf_size;
-	adj_read_subbuf = (read_subbuf + start_subbuf) % n_subbufs;
+	read_offset = read_pos % subbuf_size;
+	padding = buf->padding[read_subbuf];
 
-	if ((read_subbuf + 1) * subbuf_size <= avail) {
-		padding = buf->padding[adj_read_subbuf];
-		read_endpos = (read_subbuf + 1) * subbuf_size - padding;
+	if (read_subbuf == write_subbuf) {
+		if (read_offset + padding < write_offset)
+			avail = write_offset - (read_offset + padding);
 	} else
-		read_endpos = read_subbuf * subbuf_size + buf_offset;
+		avail = (subbuf_size - padding) - read_offset;
 
-	return read_endpos;
+	return avail;
 }
 
-/**
- *	relayfs_read_avail - return total available along with buffer start
- *
- *	Because buffers are circular, the 'beginning' of the buffer
- *	depends on where the buffer was last written.  If the writer
- *	has cycled around the buffer, the beginning is defined to be
- *	the beginning of the sub-buffer following the last sub-buffer
- *	written to, otherwise it's the beginning of sub-buffer 0.
- *
- */
-static inline size_t relayfs_read_avail(struct rchan_buf *buf,
-					size_t *start_subbuf)
+static void relayfs_read_consume(struct rchan_buf *buf,
+				 size_t read_pos,
+				 size_t bytes_consumed)
 {
-	size_t avail, complete_subbufs, cur_subbuf, buf_offset;
 	size_t subbuf_size = buf->chan->subbuf_size;
-	size_t n_subbufs = buf->chan->n_subbufs;
+	size_t read_subbuf;
+	size_t tmp;
 
-	buf_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
+	buf->bytes_consumed += bytes_consumed;
+	read_subbuf = read_pos / buf->chan->subbuf_size;
 
-	if (buf->subbufs_produced >= n_subbufs) {
-		complete_subbufs = n_subbufs - 1;
-		cur_subbuf = (buf->data - buf->start) / subbuf_size;
-		*start_subbuf = (cur_subbuf + 1) % n_subbufs;
-	} else {
-		complete_subbufs = buf->subbufs_produced;
-		*start_subbuf = 0;
+	if (buf->bytes_consumed + buf->padding[read_subbuf] == subbuf_size) {
+		tmp = buf->subbufs_consumed;
+		relay_subbufs_consumed(buf->chan, buf->cpu, 1);
+		if (buf->subbufs_consumed != tmp)
+			buf->bytes_consumed = 0;
 	}
-
-	avail = complete_subbufs * subbuf_size + buf_offset;
-
-	return avail;
 }
 
 /**
@@ -401,7 +380,7 @@
  *
  *	Reads count bytes or the number of bytes available in the
  *	current sub-buffer being read, whichever is smaller.
- *
+ *	
  *	NOTE: The results of reading a relayfs file which is currently
  *	being written to are undefined.  This is because the buffer is
  *	circular and an active writer in the kernel could be
@@ -416,31 +395,40 @@
 {
 	struct inode *inode = filp->f_dentry->d_inode;
 	struct rchan_buf *buf = RELAYFS_I(inode)->buf;
-	size_t read_start, read_end, avail, start_subbuf;
-	size_t buf_size = buf->chan->subbuf_size * buf->chan->n_subbufs;
+	size_t read_start, avail;
 	void *from;
+	long long produced, consumed;
+	size_t subbuf_size = buf->chan->subbuf_size;
+	size_t n_subbufs = buf->chan->n_subbufs;
+	size_t write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
 
-	avail = relayfs_read_avail(buf, &start_subbuf);
-	if (*ppos >= avail)
-		return 0;
+	if (buf->offset > subbuf_size)
+		produced = (buf->subbufs_produced - 1) * subbuf_size + write_offset;
+	else
+		produced = buf->subbufs_produced * subbuf_size + write_offset;
+	consumed = buf->subbufs_consumed * subbuf_size + buf->bytes_consumed;
 
-	read_start = relayfs_read_start(*ppos, avail, start_subbuf, buf);
-	if (read_start == 0 && *ppos)
+	if (produced == consumed)
 		return 0;
 
-	read_end = relayfs_read_end(read_start, avail, start_subbuf, buf);
-	if (read_end == read_start)
-		return 0;
+	relayfs_read_consume(buf, *ppos, 0);
 
-	from = buf->start + start_subbuf * buf->chan->subbuf_size + read_start;
-	if (from >= buf->start + buf_size)
-		from -= buf_size;
+	read_start = relayfs_read_start(*ppos, buf);
 
-	count = min(count, read_end - read_start);
+	avail = relayfs_read_avail(read_start, buf);
+	if (!avail)
+		return 0;
+	
+	from = buf->start + read_start;
+	count = min(count, avail);
 	if (copy_to_user(buffer, from, count))
 		return -EFAULT;
 
 	*ppos = read_start + count;
+	if (*ppos >= subbuf_size * n_subbufs)
+		*ppos = 0;
+
+	relayfs_read_consume(buf, read_start, count);
 
 	return count;
 }
--- linux-2.6.13-rc6-mm2/fs/relayfs/relay.c~	2005-08-23 14:29:08.000000000 +0200
+++ linux-2.6.13-rc6-mm2/fs/relayfs/relay.c	2005-08-23 14:29:48.000000000 +0200
@@ -58,6 +58,14 @@
 					  void *prev_subbuf,
 					  size_t prev_padding)
 {
+	if (relay_buf_full(buf)) {
+//		if (smp_processor_id() == 0) {
+//			printk("buf full, cpu %u\n", smp_processor_id());
+//			klog_printk("buf full, cpu %u\n", smp_processor_id());
+//		}
+		return 0;
+	}
+	
 	return 1;
 }
 
@@ -262,6 +270,7 @@
 	for_each_online_cpu(i) {
 		sprintf(tmpname, "%s%d", base_filename, i);
 		chan->buf[i] = relay_open_buf(chan, tmpname, parent);
+		chan->buf[i]->cpu = i;
 		if (!chan->buf[i])
 			goto free_bufs;
 	}
@@ -328,7 +337,7 @@
 	return length;
 
 toobig:
-	printk(KERN_WARNING "relayfs: event too large (%u)\n", length);
+	printk(KERN_WARNING "relayfs: event too large (%lu)\n", length);
 	WARN_ON(1);
 	return 0;
 }
--- linux-2.6.13-rc6-mm2/include/linux/relayfs_fs.h~	2005-08-23 14:29:21.000000000 +0200
+++ linux-2.6.13-rc6-mm2/include/linux/relayfs_fs.h	2005-08-23 14:29:31.000000000 +0200
@@ -22,7 +22,7 @@
 /*
  * Tracks changes to rchan_buf struct
  */
-#define RELAYFS_CHANNEL_VERSION		4
+#define RELAYFS_CHANNEL_VERSION		5
 
 /*
  * Per-cpu relay channel buffer
@@ -44,6 +44,8 @@
 	unsigned int finalized;		/* buffer has been finalized */
 	size_t *padding;		/* padding counts per sub-buffer */
 	size_t prev_padding;		/* temporary variable */
+	size_t bytes_consumed;		/* bytes consumed in cur read subbuf */
+	unsigned int cpu;		/* this buf's cpu */
 } ____cacheline_aligned;
 
 /*