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authorIlya Dryomov <idryomov@gmail.com>2016-02-17 20:04:08 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-03-03 15:06:24 -0800
commit636a9c8a87da5056b4254ff9eaf67cf52c8c2d1d (patch)
tree8da59c2a98414b6a2644d80f6c0c8d5faafa9b3e
parentb6c92a436f3e930f7d7d8d456cf3ac36602039cf (diff)
downloadlinux-linaro-stable-636a9c8a87da5056b4254ff9eaf67cf52c8c2d1d.tar.gz
libceph: don't bail early from try_read() when skipping a message
commit e7a88e82fe380459b864e05b372638aeacb0f52d upstream. The contract between try_read() and try_write() is that when called each processes as much data as possible. When instructed by osd_client to skip a message, try_read() is violating this contract by returning after receiving and discarding a single message instead of checking for more. try_write() then gets a chance to write out more requests, generating more replies/skips for try_read() to handle, forcing the messenger into a starvation loop. Reported-by: Varada Kari <Varada.Kari@sandisk.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Tested-by: Varada Kari <Varada.Kari@sandisk.com> Reviewed-by: Alex Elder <elder@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/ceph/messenger.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index e3bea2e0821a..025ced8fbb57 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -2277,7 +2277,7 @@ static int read_partial_message(struct ceph_connection *con)
con->in_base_pos = -front_len - middle_len - data_len -
sizeof(m->footer);
con->in_tag = CEPH_MSGR_TAG_READY;
- return 0;
+ return 1;
} else if ((s64)seq - (s64)con->in_seq > 1) {
pr_err("read_partial_message bad seq %lld expected %lld\n",
seq, con->in_seq + 1);
@@ -2310,7 +2310,7 @@ static int read_partial_message(struct ceph_connection *con)
sizeof(m->footer);
con->in_tag = CEPH_MSGR_TAG_READY;
con->in_seq++;
- return 0;
+ return 1;
}
BUG_ON(!con->in_msg);