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libceph: don't bail early from try_read() when skipping a message

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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.

Cc: stable@vger.kernel.org # 3.10+
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>
This commit is contained in:
Ilya Dryomov 2016-02-17 20:04:08 +01:00
parent 81f70ba233
commit e7a88e82fe
1 changed files with 2 additions and 2 deletions
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4
net/ceph/messenger.c
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@ -2337,7 +2337,7 @@ 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);
@ -2363,7 +2363,7 @@ 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);