linux/net/rds/send.c

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/*
* Copyright (c) 2006 Oracle. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
#include <linux/kernel.h>
#include <linux/moduleparam.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 09:04:11 +01:00
#include <linux/gfp.h>
#include <net/sock.h>
#include <linux/in.h>
#include <linux/list.h>
#include <linux/ratelimit.h>
#include <linux/export.h>
#include "rds.h"
/* When transmitting messages in rds_send_xmit, we need to emerge from
* time to time and briefly release the CPU. Otherwise the softlock watchdog
* will kick our shin.
* Also, it seems fairer to not let one busy connection stall all the
* others.
*
* send_batch_count is the number of times we'll loop in send_xmit. Setting
* it to 0 will restore the old behavior (where we looped until we had
* drained the queue).
*/
static int send_batch_count = 64;
module_param(send_batch_count, int, 0444);
MODULE_PARM_DESC(send_batch_count, " batch factor when working the send queue");
static void rds_send_remove_from_sock(struct list_head *messages, int status);
/*
* Reset the send state. Callers must ensure that this doesn't race with
* rds_send_xmit().
*/
void rds_send_reset(struct rds_connection *conn)
{
struct rds_message *rm, *tmp;
unsigned long flags;
if (conn->c_xmit_rm) {
rm = conn->c_xmit_rm;
conn->c_xmit_rm = NULL;
/* Tell the user the RDMA op is no longer mapped by the
* transport. This isn't entirely true (it's flushed out
* independently) but as the connection is down, there's
* no ongoing RDMA to/from that memory */
rds_message_unmapped(rm);
rds_message_put(rm);
}
conn->c_xmit_sg = 0;
conn->c_xmit_hdr_off = 0;
conn->c_xmit_data_off = 0;
conn->c_xmit_atomic_sent = 0;
conn->c_xmit_rdma_sent = 0;
conn->c_xmit_data_sent = 0;
conn->c_map_queued = 0;
conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
/* Mark messages as retransmissions, and move them to the send q */
spin_lock_irqsave(&conn->c_lock, flags);
list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags);
}
list_splice_init(&conn->c_retrans, &conn->c_send_queue);
spin_unlock_irqrestore(&conn->c_lock, flags);
}
static int acquire_in_xmit(struct rds_connection *conn)
{
return test_and_set_bit(RDS_IN_XMIT, &conn->c_flags) == 0;
}
static void release_in_xmit(struct rds_connection *conn)
{
clear_bit(RDS_IN_XMIT, &conn->c_flags);
smp_mb__after_clear_bit();
/*
* We don't use wait_on_bit()/wake_up_bit() because our waking is in a
* hot path and finding waiters is very rare. We don't want to walk
* the system-wide hashed waitqueue buckets in the fast path only to
* almost never find waiters.
*/
if (waitqueue_active(&conn->c_waitq))
wake_up_all(&conn->c_waitq);
}
/*
* We're making the conscious trade-off here to only send one message
* down the connection at a time.
* Pro:
* - tx queueing is a simple fifo list
* - reassembly is optional and easily done by transports per conn
* - no per flow rx lookup at all, straight to the socket
* - less per-frag memory and wire overhead
* Con:
* - queued acks can be delayed behind large messages
* Depends:
* - small message latency is higher behind queued large messages
* - large message latency isn't starved by intervening small sends
*/
int rds_send_xmit(struct rds_connection *conn)
{
struct rds_message *rm;
unsigned long flags;
unsigned int tmp;
struct scatterlist *sg;
int ret = 0;
LIST_HEAD(to_be_dropped);
restart:
/*
* sendmsg calls here after having queued its message on the send
* queue. We only have one task feeding the connection at a time. If
* another thread is already feeding the queue then we back off. This
* avoids blocking the caller and trading per-connection data between
* caches per message.
*/
if (!acquire_in_xmit(conn)) {
rds_stats_inc(s_send_lock_contention);
ret = -ENOMEM;
goto out;
}
/*
* rds_conn_shutdown() sets the conn state and then tests RDS_IN_XMIT,
* we do the opposite to avoid races.
*/
if (!rds_conn_up(conn)) {
release_in_xmit(conn);
ret = 0;
goto out;
}
if (conn->c_trans->xmit_prepare)
conn->c_trans->xmit_prepare(conn);
/*
* spin trying to push headers and data down the connection until
* the connection doesn't make forward progress.
*/
while (1) {
rm = conn->c_xmit_rm;
/*
* If between sending messages, we can send a pending congestion
* map update.
*/
if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
rm = rds_cong_update_alloc(conn);
if (IS_ERR(rm)) {
ret = PTR_ERR(rm);
break;
}
rm->data.op_active = 1;
conn->c_xmit_rm = rm;
}
/*
* If not already working on one, grab the next message.
*
* c_xmit_rm holds a ref while we're sending this message down
* the connction. We can use this ref while holding the
* send_sem.. rds_send_reset() is serialized with it.
*/
if (!rm) {
unsigned int len;
spin_lock_irqsave(&conn->c_lock, flags);
if (!list_empty(&conn->c_send_queue)) {
rm = list_entry(conn->c_send_queue.next,
struct rds_message,
m_conn_item);
rds_message_addref(rm);
/*
* Move the message from the send queue to the retransmit
* list right away.
*/
list_move_tail(&rm->m_conn_item, &conn->c_retrans);
}
spin_unlock_irqrestore(&conn->c_lock, flags);
if (!rm)
break;
/* Unfortunately, the way Infiniband deals with
* RDMA to a bad MR key is by moving the entire
* queue pair to error state. We cold possibly
* recover from that, but right now we drop the
* connection.
* Therefore, we never retransmit messages with RDMA ops.
*/
if (rm->rdma.op_active &&
test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
spin_lock_irqsave(&conn->c_lock, flags);
if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
list_move(&rm->m_conn_item, &to_be_dropped);
spin_unlock_irqrestore(&conn->c_lock, flags);
continue;
}
/* Require an ACK every once in a while */
len = ntohl(rm->m_inc.i_hdr.h_len);
if (conn->c_unacked_packets == 0 ||
conn->c_unacked_bytes < len) {
__set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
rds_stats_inc(s_send_ack_required);
} else {
conn->c_unacked_bytes -= len;
conn->c_unacked_packets--;
}
conn->c_xmit_rm = rm;
}
/* The transport either sends the whole rdma or none of it */
if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
rm->m_final_op = &rm->rdma;
ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
if (ret)
break;
conn->c_xmit_rdma_sent = 1;
/* The transport owns the mapped memory for now.
* You can't unmap it while it's on the send queue */
set_bit(RDS_MSG_MAPPED, &rm->m_flags);
}
if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
rm->m_final_op = &rm->atomic;
ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
if (ret)
break;
conn->c_xmit_atomic_sent = 1;
/* The transport owns the mapped memory for now.
* You can't unmap it while it's on the send queue */
set_bit(RDS_MSG_MAPPED, &rm->m_flags);
}
/*
* A number of cases require an RDS header to be sent
* even if there is no data.
* We permit 0-byte sends; rds-ping depends on this.
* However, if there are exclusively attached silent ops,
* we skip the hdr/data send, to enable silent operation.
*/
if (rm->data.op_nents == 0) {
int ops_present;
int all_ops_are_silent = 1;
ops_present = (rm->atomic.op_active || rm->rdma.op_active);
if (rm->atomic.op_active && !rm->atomic.op_silent)
all_ops_are_silent = 0;
if (rm->rdma.op_active && !rm->rdma.op_silent)
all_ops_are_silent = 0;
if (ops_present && all_ops_are_silent
&& !rm->m_rdma_cookie)
rm->data.op_active = 0;
}
if (rm->data.op_active && !conn->c_xmit_data_sent) {
rm->m_final_op = &rm->data;
ret = conn->c_trans->xmit(conn, rm,
conn->c_xmit_hdr_off,
conn->c_xmit_sg,
conn->c_xmit_data_off);
if (ret <= 0)
break;
if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) {
tmp = min_t(int, ret,
sizeof(struct rds_header) -
conn->c_xmit_hdr_off);
conn->c_xmit_hdr_off += tmp;
ret -= tmp;
}
sg = &rm->data.op_sg[conn->c_xmit_sg];
while (ret) {
tmp = min_t(int, ret, sg->length -
conn->c_xmit_data_off);
conn->c_xmit_data_off += tmp;
ret -= tmp;
if (conn->c_xmit_data_off == sg->length) {
conn->c_xmit_data_off = 0;
sg++;
conn->c_xmit_sg++;
BUG_ON(ret != 0 &&
conn->c_xmit_sg == rm->data.op_nents);
}
}
if (conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
(conn->c_xmit_sg == rm->data.op_nents))
conn->c_xmit_data_sent = 1;
}
/*
* A rm will only take multiple times through this loop
* if there is a data op. Thus, if the data is sent (or there was
* none), then we're done with the rm.
*/
if (!rm->data.op_active || conn->c_xmit_data_sent) {
conn->c_xmit_rm = NULL;
conn->c_xmit_sg = 0;
conn->c_xmit_hdr_off = 0;
conn->c_xmit_data_off = 0;
conn->c_xmit_rdma_sent = 0;
conn->c_xmit_atomic_sent = 0;
conn->c_xmit_data_sent = 0;
rds_message_put(rm);
}
}
if (conn->c_trans->xmit_complete)
conn->c_trans->xmit_complete(conn);
release_in_xmit(conn);
/* Nuke any messages we decided not to retransmit. */
if (!list_empty(&to_be_dropped)) {
/* irqs on here, so we can put(), unlike above */
list_for_each_entry(rm, &to_be_dropped, m_conn_item)
rds_message_put(rm);
rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
}
/*
* Other senders can queue a message after we last test the send queue
* but before we clear RDS_IN_XMIT. In that case they'd back off and
* not try and send their newly queued message. We need to check the
* send queue after having cleared RDS_IN_XMIT so that their message
* doesn't get stuck on the send queue.
*
* If the transport cannot continue (i.e ret != 0), then it must
* call us when more room is available, such as from the tx
* completion handler.
*/
if (ret == 0) {
smp_mb();
if (!list_empty(&conn->c_send_queue)) {
rds_stats_inc(s_send_lock_queue_raced);
goto restart;
}
}
out:
return ret;
}
static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
{
u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
assert_spin_locked(&rs->rs_lock);
BUG_ON(rs->rs_snd_bytes < len);
rs->rs_snd_bytes -= len;
if (rs->rs_snd_bytes == 0)
rds_stats_inc(s_send_queue_empty);
}
static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
is_acked_func is_acked)
{
if (is_acked)
return is_acked(rm, ack);
return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
}
/*
* This is pretty similar to what happens below in the ACK
* handling code - except that we call here as soon as we get
* the IB send completion on the RDMA op and the accompanying
* message.
*/
void rds_rdma_send_complete(struct rds_message *rm, int status)
{
struct rds_sock *rs = NULL;
struct rm_rdma_op *ro;
struct rds_notifier *notifier;
unsigned long flags;
spin_lock_irqsave(&rm->m_rs_lock, flags);
ro = &rm->rdma;
if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
ro->op_active && ro->op_notify && ro->op_notifier) {
notifier = ro->op_notifier;
rs = rm->m_rs;
sock_hold(rds_rs_to_sk(rs));
notifier->n_status = status;
spin_lock(&rs->rs_lock);
list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
spin_unlock(&rs->rs_lock);
ro->op_notifier = NULL;
}
spin_unlock_irqrestore(&rm->m_rs_lock, flags);
if (rs) {
rds_wake_sk_sleep(rs);
sock_put(rds_rs_to_sk(rs));
}
}
EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
/*
* Just like above, except looks at atomic op
*/
void rds_atomic_send_complete(struct rds_message *rm, int status)
{
struct rds_sock *rs = NULL;
struct rm_atomic_op *ao;
struct rds_notifier *notifier;
unsigned long flags;
spin_lock_irqsave(&rm->m_rs_lock, flags);
ao = &rm->atomic;
if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
&& ao->op_active && ao->op_notify && ao->op_notifier) {
notifier = ao->op_notifier;
rs = rm->m_rs;
sock_hold(rds_rs_to_sk(rs));
notifier->n_status = status;
spin_lock(&rs->rs_lock);
list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
spin_unlock(&rs->rs_lock);
ao->op_notifier = NULL;
}
spin_unlock_irqrestore(&rm->m_rs_lock, flags);
if (rs) {
rds_wake_sk_sleep(rs);
sock_put(rds_rs_to_sk(rs));
}
}
EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
/*
* This is the same as rds_rdma_send_complete except we
* don't do any locking - we have all the ingredients (message,
* socket, socket lock) and can just move the notifier.
*/
static inline void
__rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
{
struct rm_rdma_op *ro;
struct rm_atomic_op *ao;
ro = &rm->rdma;
if (ro->op_active && ro->op_notify && ro->op_notifier) {
ro->op_notifier->n_status = status;
list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
ro->op_notifier = NULL;
}
ao = &rm->atomic;
if (ao->op_active && ao->op_notify && ao->op_notifier) {
ao->op_notifier->n_status = status;
list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue);
ao->op_notifier = NULL;
}
/* No need to wake the app - caller does this */
}
/*
* This is called from the IB send completion when we detect
* a RDMA operation that failed with remote access error.
* So speed is not an issue here.
*/
struct rds_message *rds_send_get_message(struct rds_connection *conn,
struct rm_rdma_op *op)
{
struct rds_message *rm, *tmp, *found = NULL;
unsigned long flags;
spin_lock_irqsave(&conn->c_lock, flags);
list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
if (&rm->rdma == op) {
atomic_inc(&rm->m_refcount);
found = rm;
goto out;
}
}
list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
if (&rm->rdma == op) {
atomic_inc(&rm->m_refcount);
found = rm;
break;
}
}
out:
spin_unlock_irqrestore(&conn->c_lock, flags);
return found;
}
EXPORT_SYMBOL_GPL(rds_send_get_message);
/*
* This removes messages from the socket's list if they're on it. The list
* argument must be private to the caller, we must be able to modify it
* without locks. The messages must have a reference held for their
* position on the list. This function will drop that reference after
* removing the messages from the 'messages' list regardless of if it found
* the messages on the socket list or not.
*/
static void rds_send_remove_from_sock(struct list_head *messages, int status)
{
unsigned long flags;
struct rds_sock *rs = NULL;
struct rds_message *rm;
while (!list_empty(messages)) {
int was_on_sock = 0;
rm = list_entry(messages->next, struct rds_message,
m_conn_item);
list_del_init(&rm->m_conn_item);
/*
* If we see this flag cleared then we're *sure* that someone
* else beat us to removing it from the sock. If we race
* with their flag update we'll get the lock and then really
* see that the flag has been cleared.
*
* The message spinlock makes sure nobody clears rm->m_rs
* while we're messing with it. It does not prevent the
* message from being removed from the socket, though.
*/
spin_lock_irqsave(&rm->m_rs_lock, flags);
if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
goto unlock_and_drop;
if (rs != rm->m_rs) {
if (rs) {
rds_wake_sk_sleep(rs);
sock_put(rds_rs_to_sk(rs));
}
rs = rm->m_rs;
sock_hold(rds_rs_to_sk(rs));
}
spin_lock(&rs->rs_lock);
if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
struct rm_rdma_op *ro = &rm->rdma;
struct rds_notifier *notifier;
list_del_init(&rm->m_sock_item);
rds_send_sndbuf_remove(rs, rm);
if (ro->op_active && ro->op_notifier &&
(ro->op_notify || (ro->op_recverr && status))) {
notifier = ro->op_notifier;
list_add_tail(&notifier->n_list,
&rs->rs_notify_queue);
if (!notifier->n_status)
notifier->n_status = status;
rm->rdma.op_notifier = NULL;
}
was_on_sock = 1;
rm->m_rs = NULL;
}
spin_unlock(&rs->rs_lock);
unlock_and_drop:
spin_unlock_irqrestore(&rm->m_rs_lock, flags);
rds_message_put(rm);
if (was_on_sock)
rds_message_put(rm);
}
if (rs) {
rds_wake_sk_sleep(rs);
sock_put(rds_rs_to_sk(rs));
}
}
/*
* Transports call here when they've determined that the receiver queued
* messages up to, and including, the given sequence number. Messages are
* moved to the retrans queue when rds_send_xmit picks them off the send
* queue. This means that in the TCP case, the message may not have been
* assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
* checks the RDS_MSG_HAS_ACK_SEQ bit.
*
* XXX It's not clear to me how this is safely serialized with socket
* destruction. Maybe it should bail if it sees SOCK_DEAD.
*/
void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
is_acked_func is_acked)
{
struct rds_message *rm, *tmp;
unsigned long flags;
LIST_HEAD(list);
spin_lock_irqsave(&conn->c_lock, flags);
list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
if (!rds_send_is_acked(rm, ack, is_acked))
break;
list_move(&rm->m_conn_item, &list);
clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
}
/* order flag updates with spin locks */
if (!list_empty(&list))
smp_mb__after_clear_bit();
spin_unlock_irqrestore(&conn->c_lock, flags);
/* now remove the messages from the sock list as needed */
rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
}
EXPORT_SYMBOL_GPL(rds_send_drop_acked);
void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
{
struct rds_message *rm, *tmp;
struct rds_connection *conn;
unsigned long flags;
LIST_HEAD(list);
/* get all the messages we're dropping under the rs lock */
spin_lock_irqsave(&rs->rs_lock, flags);
list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
dest->sin_port != rm->m_inc.i_hdr.h_dport))
continue;
list_move(&rm->m_sock_item, &list);
rds_send_sndbuf_remove(rs, rm);
clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
}
/* order flag updates with the rs lock */
smp_mb__after_clear_bit();
spin_unlock_irqrestore(&rs->rs_lock, flags);
if (list_empty(&list))
return;
/* Remove the messages from the conn */
list_for_each_entry(rm, &list, m_sock_item) {
conn = rm->m_inc.i_conn;
spin_lock_irqsave(&conn->c_lock, flags);
/*
* Maybe someone else beat us to removing rm from the conn.
* If we race with their flag update we'll get the lock and
* then really see that the flag has been cleared.
*/
if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
spin_unlock_irqrestore(&conn->c_lock, flags);
continue;
}
list_del_init(&rm->m_conn_item);
spin_unlock_irqrestore(&conn->c_lock, flags);
/*
* Couldn't grab m_rs_lock in top loop (lock ordering),
* but we can now.
*/
spin_lock_irqsave(&rm->m_rs_lock, flags);
spin_lock(&rs->rs_lock);
__rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
spin_unlock(&rs->rs_lock);
rm->m_rs = NULL;
spin_unlock_irqrestore(&rm->m_rs_lock, flags);
rds_message_put(rm);
}
rds_wake_sk_sleep(rs);
while (!list_empty(&list)) {
rm = list_entry(list.next, struct rds_message, m_sock_item);
list_del_init(&rm->m_sock_item);
rds_message_wait(rm);
rds_message_put(rm);
}
}
/*
* we only want this to fire once so we use the callers 'queued'. It's
* possible that another thread can race with us and remove the
* message from the flow with RDS_CANCEL_SENT_TO.
*/
static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
struct rds_message *rm, __be16 sport,
__be16 dport, int *queued)
{
unsigned long flags;
u32 len;
if (*queued)
goto out;
len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
/* this is the only place which holds both the socket's rs_lock
* and the connection's c_lock */
spin_lock_irqsave(&rs->rs_lock, flags);
/*
* If there is a little space in sndbuf, we don't queue anything,
* and userspace gets -EAGAIN. But poll() indicates there's send
* room. This can lead to bad behavior (spinning) if snd_bytes isn't
* freed up by incoming acks. So we check the *old* value of
* rs_snd_bytes here to allow the last msg to exceed the buffer,
* and poll() now knows no more data can be sent.
*/
if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
rs->rs_snd_bytes += len;
/* let recv side know we are close to send space exhaustion.
* This is probably not the optimal way to do it, as this
* means we set the flag on *all* messages as soon as our
* throughput hits a certain threshold.
*/
if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
__set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
rds_message_addref(rm);
rm->m_rs = rs;
/* The code ordering is a little weird, but we're
trying to minimize the time we hold c_lock */
rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
rm->m_inc.i_conn = conn;
rds_message_addref(rm);
spin_lock(&conn->c_lock);
rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
spin_unlock(&conn->c_lock);
rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
rm, len, rs, rs->rs_snd_bytes,
(unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
*queued = 1;
}
spin_unlock_irqrestore(&rs->rs_lock, flags);
out:
return *queued;
}
/*
* rds_message is getting to be quite complicated, and we'd like to allocate
* it all in one go. This figures out how big it needs to be up front.
*/
static int rds_rm_size(struct msghdr *msg, int data_len)
{
struct cmsghdr *cmsg;
int size = 0;
int cmsg_groups = 0;
int retval;
for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
if (!CMSG_OK(msg, cmsg))
return -EINVAL;
if (cmsg->cmsg_level != SOL_RDS)
continue;
switch (cmsg->cmsg_type) {
case RDS_CMSG_RDMA_ARGS:
cmsg_groups |= 1;
retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
if (retval < 0)
return retval;
size += retval;
break;
case RDS_CMSG_RDMA_DEST:
case RDS_CMSG_RDMA_MAP:
cmsg_groups |= 2;
/* these are valid but do no add any size */
break;
case RDS_CMSG_ATOMIC_CSWP:
case RDS_CMSG_ATOMIC_FADD:
case RDS_CMSG_MASKED_ATOMIC_CSWP:
case RDS_CMSG_MASKED_ATOMIC_FADD:
cmsg_groups |= 1;
size += sizeof(struct scatterlist);
break;
default:
return -EINVAL;
}
}
size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
/* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
if (cmsg_groups == 3)
return -EINVAL;
return size;
}
static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
struct msghdr *msg, int *allocated_mr)
{
struct cmsghdr *cmsg;
int ret = 0;
for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
if (!CMSG_OK(msg, cmsg))
return -EINVAL;
if (cmsg->cmsg_level != SOL_RDS)
continue;
/* As a side effect, RDMA_DEST and RDMA_MAP will set
* rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
*/
switch (cmsg->cmsg_type) {
case RDS_CMSG_RDMA_ARGS:
ret = rds_cmsg_rdma_args(rs, rm, cmsg);
break;
case RDS_CMSG_RDMA_DEST:
ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
break;
case RDS_CMSG_RDMA_MAP:
ret = rds_cmsg_rdma_map(rs, rm, cmsg);
if (!ret)
*allocated_mr = 1;
break;
case RDS_CMSG_ATOMIC_CSWP:
case RDS_CMSG_ATOMIC_FADD:
case RDS_CMSG_MASKED_ATOMIC_CSWP:
case RDS_CMSG_MASKED_ATOMIC_FADD:
ret = rds_cmsg_atomic(rs, rm, cmsg);
break;
default:
return -EINVAL;
}
if (ret)
break;
}
return ret;
}
int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
size_t payload_len)
{
struct sock *sk = sock->sk;
struct rds_sock *rs = rds_sk_to_rs(sk);
struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
__be32 daddr;
__be16 dport;
struct rds_message *rm = NULL;
struct rds_connection *conn;
int ret = 0;
int queued = 0, allocated_mr = 0;
int nonblock = msg->msg_flags & MSG_DONTWAIT;
long timeo = sock_sndtimeo(sk, nonblock);
/* Mirror Linux UDP mirror of BSD error message compatibility */
/* XXX: Perhaps MSG_MORE someday */
if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
ret = -EOPNOTSUPP;
goto out;
}
if (msg->msg_namelen) {
/* XXX fail non-unicast destination IPs? */
if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
ret = -EINVAL;
goto out;
}
daddr = usin->sin_addr.s_addr;
dport = usin->sin_port;
} else {
/* We only care about consistency with ->connect() */
lock_sock(sk);
daddr = rs->rs_conn_addr;
dport = rs->rs_conn_port;
release_sock(sk);
}
/* racing with another thread binding seems ok here */
if (daddr == 0 || rs->rs_bound_addr == 0) {
ret = -ENOTCONN; /* XXX not a great errno */
goto out;
}
/* size of rm including all sgs */
ret = rds_rm_size(msg, payload_len);
if (ret < 0)
goto out;
rm = rds_message_alloc(ret, GFP_KERNEL);
if (!rm) {
ret = -ENOMEM;
goto out;
}
/* Attach data to the rm */
if (payload_len) {
rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
if (!rm->data.op_sg) {
ret = -ENOMEM;
goto out;
}
ret = rds_message_copy_from_user(rm, msg->msg_iov, payload_len);
if (ret)
goto out;
}
rm->data.op_active = 1;
rm->m_daddr = daddr;
/* rds_conn_create has a spinlock that runs with IRQ off.
* Caching the conn in the socket helps a lot. */
if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
conn = rs->rs_conn;
else {
conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr,
rs->rs_transport,
sock->sk->sk_allocation);
if (IS_ERR(conn)) {
ret = PTR_ERR(conn);
goto out;
}
rs->rs_conn = conn;
}
/* Parse any control messages the user may have included. */
ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
if (ret)
goto out;
if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
printk_ratelimited(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
&rm->rdma, conn->c_trans->xmit_rdma);
ret = -EOPNOTSUPP;
goto out;
}
if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
printk_ratelimited(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
&rm->atomic, conn->c_trans->xmit_atomic);
ret = -EOPNOTSUPP;
goto out;
}
rds_conn_connect_if_down(conn);
ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
if (ret) {
rs->rs_seen_congestion = 1;
goto out;
}
while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
dport, &queued)) {
rds_stats_inc(s_send_queue_full);
/* XXX make sure this is reasonable */
if (payload_len > rds_sk_sndbuf(rs)) {
ret = -EMSGSIZE;
goto out;
}
if (nonblock) {
ret = -EAGAIN;
goto out;
}
timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
rds_send_queue_rm(rs, conn, rm,
rs->rs_bound_port,
dport,
&queued),
timeo);
rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
continue;
ret = timeo;
if (ret == 0)
ret = -ETIMEDOUT;
goto out;
}
/*
* By now we've committed to the send. We reuse rds_send_worker()
* to retry sends in the rds thread if the transport asks us to.
*/
rds_stats_inc(s_send_queued);
if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
rds_send_xmit(conn);
rds_message_put(rm);
return payload_len;
out:
/* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
* If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
* or in any other way, we need to destroy the MR again */
if (allocated_mr)
rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
if (rm)
rds_message_put(rm);
return ret;
}
/*
* Reply to a ping packet.
*/
int
rds_send_pong(struct rds_connection *conn, __be16 dport)
{
struct rds_message *rm;
unsigned long flags;
int ret = 0;
rm = rds_message_alloc(0, GFP_ATOMIC);
if (!rm) {
ret = -ENOMEM;
goto out;
}
rm->m_daddr = conn->c_faddr;
rm->data.op_active = 1;
rds_conn_connect_if_down(conn);
ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
if (ret)
goto out;
spin_lock_irqsave(&conn->c_lock, flags);
list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
rds_message_addref(rm);
rm->m_inc.i_conn = conn;
rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
conn->c_next_tx_seq);
conn->c_next_tx_seq++;
spin_unlock_irqrestore(&conn->c_lock, flags);
rds_stats_inc(s_send_queued);
rds_stats_inc(s_send_pong);
if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
rds_send_xmit(conn);
rds_message_put(rm);
return 0;
out:
if (rm)
rds_message_put(rm);
return ret;
}