Fixes: 9426bbc6 ("rds: use list structure to track information for zerocopy completion notification")
Signed-off-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes: d40a126b ("rds: refactor zcopy code into rds_message_zcopy_from_user")
Signed-off-by: NFengguang Wu <fengguang.wu@intel.com>
Acked-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 401910db ("rds: deliver zerocopy completion notification
with data") removes support fo r zerocopy completion notification
on the sk_error_queue, thus we no longer need to track the cookie
information in sk_buff structures.

This commit removes the struct sk_buff_head rs_zcookie_queue by
a simpler list that results in a smaller memory footprint as well
as more efficient memory_allocation time.
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move the large block of code predicated on zcopy from
rds_message_copy_from_user into a new function,
rds_message_zcopy_from_user()
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This commit is an optimization over commit 01883eda
("rds: support for zcopy completion notification") for PF_RDS sockets.

RDS applications are predominantly request-response transactions, so
it is more efficient to reduce the number of system calls and have
zerocopy completion notification delivered as ancillary data on the
POLLIN channel.

Cookies are passed up as ancillary data (at level SOL_RDS) in a
struct rds_zcopy_cookies when the returned value of recvmsg() is
greater than, or equal to, 0. A max of RDS_MAX_ZCOOKIES may be passed
with each message.

This commit removes support for zerocopy completion notification on
MSG_ERRQUEUE for PF_RDS sockets.
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If the MSG_ZEROCOPY flag is specified with rds_sendmsg(), and,
if the SO_ZEROCOPY socket option has been set on the PF_RDS socket,
application pages sent down with rds_sendmsg() are pinned.

The pinning uses the accounting infrastructure added by
Commit a91dbff5 ("sock: ulimit on MSG_ZEROCOPY pages")

The payload bytes in the message may not be modified for the
duration that the message has been pinned. A multi-threaded
application using this infrastructure may thus need to be notified
about send-completion so that it can free/reuse the buffers
passed to rds_sendmsg(). Notification of send-completion will
identify each message-buffer by a cookie that the application
must specify as ancillary data to rds_sendmsg().
The ancillary data in this case has cmsg_level == SOL_RDS
and cmsg_type == RDS_CMSG_ZCOPY_COOKIE.
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@oracle.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

RDS removes a datagram (rds_message) from the retransmit queue when
an ACK is received. The ACK indicates that the receiver has queued
the RDS datagram, so that the sender can safely forget the datagram.
When all references to the rds_message are quiesced, rds_message_purge
is called to release resources used by the rds_message

If the datagram to be removed had pinned pages set up, add
an entry to the rs->rs_znotify_queue so that the notifcation
will be sent up via rds_rm_zerocopy_callback() when the
rds_message is eventually freed by rds_message_purge.

rds_rm_zerocopy_callback() attempts to batch the number of cookies
sent with each notification  to a max of SO_EE_ORIGIN_MAX_ZCOOKIES.
This is achieved by checking the tail skb in the sk_error_queue:
if this has room for one more cookie, the cookie from the
current notification is added; else a new skb is added to the
sk_error_queue. Every invocation of rds_rm_zerocopy_callback() will
trigger a ->sk_error_report to notify the application.
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@oracle.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The existing model holds a reference from the rds_sock to the
rds_message, but the rds_message does not itself hold a sock_put()
on the rds_sock. Instead the m_rs field in the rds_message is
assigned when the message is queued on the sock, and nulled when
the message is dequeued from the sock.

We want to be able to notify userspace when the rds_message
is actually freed (from rds_message_purge(), after the refcounts
to the rds_message go to 0). At the time that rds_message_purge()
is called, the message is no longer on the rds_sock retransmit
queue. Thus the explicit reference for the m_rs is needed to
send a notification that will signal to userspace that
it is now safe to free/reuse any pages that may have
been pinned down for zerocopy.

This patch manages the m_rs assignment in the rds_message with
the necessary refcount book-keeping.
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The RDS transport has to be able to distinguish between
two types of failure events:
(a) when the transport fails (e.g., TCP connection reset)
    but the RDS socket/connection layer on both sides stays
    the same
(b) when the peer's RDS layer itself resets (e.g., due to module
    reload or machine reboot at the peer)
In case (a) both sides must reconnect and continue the RDS messaging
without any message loss or disruption to the message sequence numbers,
and this is achieved by rds_send_path_reset().

In case (b) we should reset all rds_connection state to the
new incarnation of the peer. Examples of state that needs to
be reset are next expected rx sequence number from, or messages to be
retransmitted to, the new incarnation of the peer.

To achieve this, the RDS handshake probe added as part of
commit 5916e2c1 ("RDS: TCP: Enable multipath RDS for TCP")
is enhanced so that sender and receiver of the RDS ping-probe
will add a generation number as part of the RDS_EXTHDR_GEN_NUM
extension header. Each peer stores local and remote generation
numbers as part of each rds_connection. Changes in generation
number will be detected via incoming handshake probe ping
request or response and will allow the receiver to reset rds_connection
state.
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use RDS probe-ping to compute how many paths may be used with
the peer, and to synchronously start the multiple paths. If mprds is
supported, hash outgoing traffic to one of multiple paths in rds_sendmsg()
when multipath RDS is supported by the transport.

CC: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 083735f4 ("rds: switch rds_message_copy_from_user() to iov_iter")
breaks rds_message_copy_from_user() semantics on success, and causes it
to return nbytes copied, when it should return 0.  This commit fixes that bug.
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/rds/message.c: In function ‘rds_message_inc_copy_to_user’:
net/rds/message.c:328: warning: comparison of distinct pointer types lacks a cast

Use min_t(unsigned long, ...) like is done in
rds_message_copy_from_user().
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

instances get considerably simpler from that...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: David S. Miller <davem@davemloft.net>
Cc: Venkat Venkatsubra <venkat.x.venkatsubra@oracle.com>
Signed-off-by: NCong Wang <amwang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Dave Jones reported the following bug:

"When fed mangled socket data, rds will trust what userspace gives it,
and tries to allocate enormous amounts of memory larger than what
kmalloc can satisfy."

WARNING: at mm/page_alloc.c:2393 __alloc_pages_nodemask+0xa0d/0xbe0()
Hardware name: GA-MA78GM-S2H
Modules linked in: vmw_vsock_vmci_transport vmw_vmci vsock fuse bnep dlci bridge 8021q garp stp mrp binfmt_misc l2tp_ppp l2tp_core rfcomm s
Pid: 24652, comm: trinity-child2 Not tainted 3.8.0+ #65
Call Trace:
 [<ffffffff81044155>] warn_slowpath_common+0x75/0xa0
 [<ffffffff8104419a>] warn_slowpath_null+0x1a/0x20
 [<ffffffff811444ad>] __alloc_pages_nodemask+0xa0d/0xbe0
 [<ffffffff8100a196>] ? native_sched_clock+0x26/0x90
 [<ffffffff810b2128>] ? trace_hardirqs_off_caller+0x28/0xc0
 [<ffffffff810b21cd>] ? trace_hardirqs_off+0xd/0x10
 [<ffffffff811861f8>] alloc_pages_current+0xb8/0x180
 [<ffffffff8113eaaa>] __get_free_pages+0x2a/0x80
 [<ffffffff811934fe>] kmalloc_order_trace+0x3e/0x1a0
 [<ffffffff81193955>] __kmalloc+0x2f5/0x3a0
 [<ffffffff8104df0c>] ? local_bh_enable_ip+0x7c/0xf0
 [<ffffffffa0401ab3>] rds_message_alloc+0x23/0xb0 [rds]
 [<ffffffffa04043a1>] rds_sendmsg+0x2b1/0x990 [rds]
 [<ffffffff810b21cd>] ? trace_hardirqs_off+0xd/0x10
 [<ffffffff81564620>] sock_sendmsg+0xb0/0xe0
 [<ffffffff810b2052>] ? get_lock_stats+0x22/0x70
 [<ffffffff810b24be>] ? put_lock_stats.isra.23+0xe/0x40
 [<ffffffff81567f30>] sys_sendto+0x130/0x180
 [<ffffffff810b872d>] ? trace_hardirqs_on+0xd/0x10
 [<ffffffff816c547b>] ? _raw_spin_unlock_irq+0x3b/0x60
 [<ffffffff816cd767>] ? sysret_check+0x1b/0x56
 [<ffffffff810b8695>] ? trace_hardirqs_on_caller+0x115/0x1a0
 [<ffffffff81341d8e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
 [<ffffffff816cd742>] system_call_fastpath+0x16/0x1b
---[ end trace eed6ae990d018c8b ]---
Reported-by: NDave Jones <davej@redhat.com>
Cc: Dave Jones <davej@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Venkat Venkatsubra <venkat.x.venkatsubra@oracle.com>
Signed-off-by: NCong Wang <amwang@redhat.com>
Acked-by: NVenkat Venkatsubra <venkat.x.venkatsubra@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NPaul Gortmaker <paul.gortmaker@windriver.com>

The sgs allocation error path leaks the allocated message.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Acked-by: NAndy Grover <andy.grover@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Even with the previous fix, we still are reading the iovecs once
to determine SGs needed, and then again later on. Preallocating
space for sg lists as part of rds_message seemed like a good idea
but it might be better to not do this. While working to redo that
code, this patch attempts to protect against userspace rewriting
the rds_iovec array between the first and second accesses.

The consequences of this would be either a too-small or too-large
sg list array. Too large is not an issue. This patch changes all
callers of message_alloc_sgs to handle running out of preallocated
sgs, and fail gracefully.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The RDS protocol has lots of functions that should be
declared static. rds_message_get/add_version_extension is
removed since it defined but never used.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is the first in a long line of patches that tries to fix races
between RDS connection shutdown and RDS traffic.

Here we are maintaining a count of active senders to make sure
the connection doesn't go away while they are using it.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This removes a global waitqueue used to wait for rds messages
and replaces it with a waitqueue inside the rds_message struct.

The global waitqueue turns into a global lock and significantly
bottlenecks operations on large machines.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Can't see a reason not to allow signals to interrupt the wait.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

If the queue has nobody on it, then wake_up does nothing.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

Can no longer block, so use NOWAIT.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

rds_message_alloc_sgs() only works when nents is nonzero.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

Do not allocate sgs for data for 0-length datagrams

Set data.op_active in rds_sendmsg() instead of
rds_message_copy_from_user().
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

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

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>

Add atomic_free_op function, analogous to rdma_free_op,
and call it in rds_message_purge().
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

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

Also, try to better-document the locking around the
rm and its m_inc in loop.c.
Signed-off-by: NAndy Grover <andy.grover@oracle.com>

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

rds_message_alloc_sgs() now returns correctly-initialized
sg lists, so calleds need not do this themselves.
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>

r_m_copy_from_user used to allocate the rm as well as kernel
buffers for the data, and then copy the data in. Now, sendmsg()
allocates the rm, although the data buffer alloc still happens
in r_m_copy_from_user.

SGs are still allocated with rm, but now r_m_alloc_sgs() is
used to reserve them. This allows multiple SG lists to be
allocated from the one rm -- this is important once we also
want to alloc our rdma sgl from this pool.
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>