This is essential, as for the rados block device we'll need
to run in different contexts that would need flags that
are other than GFP_NOFS.
Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
We only need to pass in front_len. Callers can attach any other payload
pieces (middle, data) as they see fit.
Signed-off-by: Sage Weil <sage@newdream.net>
Returning ERR_PTR(-ENOMEM) is useless extra work. Return NULL on failure
instead, and fix up the callers (about half of which were wrong anyway).
Signed-off-by: Sage Weil <sage@newdream.net>
Since we don't need to maintain large pools of messages, we can just
use the standard mempool_t. We maintain a msgpool 'wrapper' because we
need the mempool_t* in the alloc function, and mempool gives us only
pool_data.
Signed-off-by: Sage Weil <sage@newdream.net>
Reset msg front len when a message is returned to the pool: the caller
may have changed it.
BUG if we try to send a message with a hdr.front_len that doesn't match
the front iov.
Signed-off-by: Sage Weil <sage@newdream.net>
Pass the front_len we need when pulling a message off a msgpool,
and WARN if it is greater than the pool's size. Then try to
allocate a new message (to continue without failing).
Signed-off-by: Sage Weil <sage@newdream.net>
The msgpool is a basic mempool_t-like structure to preallocate
messages we expect to receive over the wire. This ensures we have the
necessary memory preallocated to process replies to requests, or to
process unsolicited messages from various servers.
Signed-off-by: Sage Weil <sage@newdream.net>
