diff options
| author | Tom Zanussi <tzanussi@gmail.com> | 2008-08-06 00:05:03 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-08-20 11:15:23 -0700 |
| commit | 435d30c6e982de6c1c4ec5727445657cdb3009ef (patch) | |
| tree | 36acf4ad02b68359c04da044ece248e1c24d7bf4 | |
| parent | cf6d7d728ac241a86939d1dcb89ad62ce9d8ce5d (diff) | |
relay: fix "full buffer with exactly full last subbuffer" accounting problem
commit 32194450330be327f3b25bf6b66298bd122599e9 upstream
In relay's current read implementation, if the buffer is completely full
but hasn't triggered the buffer-full condition (i.e. the last write
didn't cross the subbuffer boundary) and the last subbuffer is exactly
full, the subbuffer accounting code erroneously finds nothing available.
This patch fixes the problem.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Andrea Righi <righi.andrea@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | kernel/relay.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/kernel/relay.c b/kernel/relay.c index d6204a48581..ee2e614a344 100644 --- a/kernel/relay.c +++ b/kernel/relay.c @@ -803,6 +803,10 @@ static void relay_file_read_consume(struct rchan_buf *buf, size_t n_subbufs = buf->chan->n_subbufs; size_t read_subbuf; + if (buf->subbufs_produced == buf->subbufs_consumed && + buf->offset == buf->bytes_consumed) + return; + if (buf->bytes_consumed + bytes_consumed > subbuf_size) { relay_subbufs_consumed(buf->chan, buf->cpu, 1); buf->bytes_consumed = 0; @@ -834,6 +838,8 @@ static int relay_file_read_avail(struct rchan_buf *buf, size_t read_pos) relay_file_read_consume(buf, read_pos, 0); + consumed = buf->subbufs_consumed; + if (unlikely(buf->offset > subbuf_size)) { if (produced == consumed) return 0; @@ -852,8 +858,12 @@ static int relay_file_read_avail(struct rchan_buf *buf, size_t read_pos) if (consumed > produced) produced += n_subbufs * subbuf_size; - if (consumed == produced) + if (consumed == produced) { + if (buf->offset == subbuf_size && + buf->subbufs_produced > buf->subbufs_consumed) + return 1; return 0; + } return 1; } |