From a66e356c04ece4a96f44b942b68234c3de8ec3f5 Mon Sep 17 00:00:00 2001
From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Date: Wed, 27 Jun 2007 14:10:04 -0700
Subject: [PATCH] relayfs: fix overwrites
When I use relayfs with "overwrite" mode, read() still sets incorrect
number of consumed bytes.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Tom Zanussi <zanussi@us.ibm.com>
Acked-by: David Wilder <dwilder@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
kernel/relay.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/kernel/relay.c b/kernel/relay.c
index e61156ea4e25..95db8c79fe8f 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -812,7 +812,10 @@ static void relay_file_read_consume(struct rchan_buf *buf,
}
buf->bytes_consumed += bytes_consumed;
- read_subbuf = read_pos / buf->chan->subbuf_size;
+ if (!read_pos)
+ read_subbuf = buf->subbufs_consumed % n_subbufs;
+ else
+ read_subbuf = read_pos / buf->chan->subbuf_size;
if (buf->bytes_consumed + buf->padding[read_subbuf] == subbuf_size) {
if ((read_subbuf == buf->subbufs_produced % n_subbufs) &&
(buf->offset == subbuf_size))
@@ -841,8 +844,9 @@ static int relay_file_read_avail(struct rchan_buf *buf, size_t read_pos)
}
if (unlikely(produced - consumed >= n_subbufs)) {
- consumed = (produced / n_subbufs) * n_subbufs;
+ consumed = produced - n_subbufs + 1;
buf->subbufs_consumed = consumed;
+ buf->bytes_consumed = 0;
}
produced = (produced % n_subbufs) * subbuf_size + buf->offset;
--
2.20.1