A big changeset, but it's all pretty dumb.

struct rds_rdma_op was already embedded in struct rm_rdma_op.
Remove rds_rdma_op and put its members in rm_rdma_op. Rename
members with "op_" prefix instead of "r_", for consistency.

Of course this breaks a lot, so fixup the code accordingly.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

Signed-off-by: NAndy Grover <andy.grover@oracle.com>

Maybe things worked fine with the flow control code running
even in the non-flow-control case, but making it explicitly
conditional helps the non-fc case be easier to read.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

Removed unsignaled_bytes sysctl and code to signal
based on it. I believe unsignaled_wrs is more than
sufficient for our purposes.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

Now that the header always goes first, it is possible to
simplify rds_ib_xmit. Instead of having a path to handle 0-byte
dgrams and another path to handle >0, these can both be handled
in one path. This lets us eliminate xmit_populate_wr().

Rename sent to bytes_sent, to differentiate better from other
variable named "send".
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

These functions were to cope with differently ordered
sg entries depending on RDS 3.0 or 3.1+. Now that
we've dropped 3.0 compatibility we no longer need them.

Also, modify usage sites for these to refer to sge[0] or [1]
directly. Reorder code to initialize header sgs first.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

Signed-off-by: NAndy Grover <andy.grover@oracle.com>

both atomics and rdmas need to convert ib-specific completion codes
into RDS status codes. Rename rds_ib_rdma_send_complete to
rds_ib_send_complete, and have it take a pointer to the function to
call with the new error code.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

Implement a CMSG-based interface to do FADD and CSWP ops.

Alter send routines to handle atomic ops.

Add atomic counters to stats.

Add xmit_atomic() to struct rds_transport

Inline rds_ib_send_unmap_rdma into unmap_rm
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

This eliminates a separate memory alloc, although
it is now necessary to add an "r_active" flag, since
it is no longer to use the m_rdma_op pointer as an
indicator of if an rdma op is present.

rdma SGs allocated from rm sg pool.

rds_rm_size also gets bigger. It's a little inefficient to
run through CMSGs twice, but it makes later steps a lot smoother.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

RDMA is now an intrinsic part of RDS, so it's easier to just have
a single header.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

Clearly separate rdma-related variables in rm from data-related ones.
This is in anticipation of adding atomic support.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

Favor "if (foo)" style over "if (foo != NULL)".
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

If the RDMA op has aborted with a remote access error,
in addition to what we already do (tell userspace it has
completed with an error) also unmap it and put() the rm.

Otherwise, hangs may occur on arches that track maps and
will not exit without proper cleanup.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We have two kinds of loopback: software (via loop transport)
and hardware (via IB). sw is used for 127.0.0.1, and doesn't
support rdma ops. hw is used for sends to local device IPs,
and supports rdma. Both are used in different cases.

For both of these, when there is a congestion map update, we
want to call rds_cong_map_updated() but not actually send
anything -- since loopback local and foreign congestion maps
point to the same spot, they're already in sync.

The old code never called sw loop's xmit_cong_map(),so
rds_cong_map_updated() wasn't being called for it. sw loop
ports would not work right with the congestion monitor.

Fixing that meant that hw loopback now would send congestion maps
to itself. This is also undesirable (racy), so we check for this
case in the ib-specific xmit code.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

BUGging on a runtime error code should be avoided. This
patch also eliminates all other BUG()s that have no real
reason to exist.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Not including net/atm/

Compiled tested x86 allyesconfig only
Added a > 80 column line or two, which I ignored.
Existing checkpatch plaints willfully, cheerfully ignored.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix hack that restricts the credit advertisement to 127.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NAndy Grover <andy.grover@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The RDS_LL_SEND_FULL bit should be set when we stop transmitted due to
flow control.  Otherwise the send worker will keep trying as opposed to
sleeping until we unthrottle.  Saves CPU.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NAndy Grover <andy.grover@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Specific to IB is a credits-based flow control mechanism, in
addition to the expected usage of the IB API to package outgoing
data into work requests.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>