rds: check for excessive looping in rds_send_xmit

Original commit from 2011 updated to include a change by
Yuval Shaia <yuval.shaia@oracle.com>
that adds a new statistic counter "send_stuck_rm"
to capture the messages looping exessively
in the send path.

Signed-off-by: Gerd Rausch <gerd.rausch@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds: Add a few missing rds_stat_names entries

In a previous commit, fields were added to "struct rds_statistics"
but array "rds_stat_names" was not updated accordingly.

Please note the inconsistent naming of the string representations
that is done in the name of compatibility
with the Oracle internal code-base.

s_recv_bytes_added_to_socket -> "recv_bytes_added_to_sock"
s_recv_bytes_removed_from_socket -> "recv_bytes_freed_fromsock"

Fixes: 192a798f5299 ("RDS: add stat for socket recv memory usage")
Signed-off-by: Gerd Rausch <gerd.rausch@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds: zero last byte for strncpy

for NUL terminated string, need be always sure '\0' in the end.

additional info:
strncpy will pads with zeroes to the end of the given buffer.
should initialise every bit of memory that is going to be copied to userland

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules

These files are non modular, but need to export symbols using
the macros now living in export.h -- call out the include so
that things won't break when we remove the implicit presence
of module.h from everywhere.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

RDS: remove __init and __exit annotation

The trivial amount of memory saved isn't worth the cost of dealing with section
mismatches.

Signed-off-by: Zach Brown <zach.brown@oracle.com>

RDS: Move atomic stats from general to ib-specific area

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

RDS: Change send lock from a mutex to a spinlock

This change allows us to call rds_send_xmit() from a tasklet,
which is crucial to our new operating model.

* Change c_send_lock to a spinlock
* Update stats fields "sem_" to "_lock"
* Remove unneeded rds_conn_is_sending()

About locking between shutdown and send -- send checks if the
connection is up. Shutdown puts the connection into
DISCONNECTING. After this, all threads entering send will exit
immediately. However, a thread could be *in* send_xmit(), so
shutdown acquires the c_send_lock to ensure everyone is out
before proceeding with connection shutdown.

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

RDS: Implement atomic operations

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: Andy Grover <andy.grover@oracle.com>

RDS: Export symbols from core RDS

Now that rdma and tcp transports will be modularized,
we need to export a number of functions so they can call them.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mark read-only arrays as const

String literals are constant, and usually, we can also tag the array
of pointers const too, moving it to the .rodata section.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

RDS: Info and stats

RDS currently generates a lot of stats that are accessible via
the rds-info utility. This code implements the support for this.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>