Commit Graph

268 Commits

Author SHA1 Message Date
Andy Grover f4a3fc03c1 RDS: Clean up error handling in rds_cmsg_rdma_args
We don't need to set ret = 0 at the end -- it's initialized to 0.

Also, don't increment s_send_rdma stat if we're exiting with an
error.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-10-30 16:34:17 -07:00
Andy Grover a09f69c49b RDS: Return -EINVAL if rds_rdma_pages returns an error
rds_cmsg_rdma_args would still return success even if rds_rdma_pages
returned an error (or overflowed).

Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-10-30 16:34:16 -07:00
Linus Torvalds 1b1f693d7a net: fix rds_iovec page count overflow
As reported by Thomas Pollet, the rdma page counting can overflow.  We
get the rdma sizes in 64-bit unsigned entities, but then limit it to
UINT_MAX bytes and shift them down to pages (so with a possible "+1" for
an unaligned address).

So each individual page count fits comfortably in an 'unsigned int' (not
even close to overflowing into signed), but as they are added up, they
might end up resulting in a signed return value. Which would be wrong.

Catch the case of tot_pages turning negative, and return the appropriate
error code.

Reported-by: Thomas Pollet <thomas.pollet@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-10-30 16:34:16 -07:00
David S. Miller 2198a10b50 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
	net/core/dev.c
2010-10-21 08:43:05 -07:00
stephen hemminger ff51bf8415 rds: make local functions/variables static
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: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-10-21 04:26:39 -07:00
Linus Torvalds 799c10559d De-pessimize rds_page_copy_user
Don't try to "optimize" rds_page_copy_user() by using kmap_atomic() and
the unsafe atomic user mode accessor functions.  It's actually slower
than the straightforward code on any reasonable modern CPU.

Back when the code was written (although probably not by the time it was
actually merged, though), 32-bit x86 may have been the dominant
architecture.  And there kmap_atomic() can be a lot faster than kmap()
(unless you have very good locality, in which case the virtual address
caching by kmap() can overcome all the downsides).

But these days, x86-64 may not be more populous, but it's getting there
(and if you care about performance, it's definitely already there -
you'd have upgraded your CPU's already in the last few years).  And on
x86-64, the non-kmap_atomic() version is faster, simply because the code
is simpler and doesn't have the "re-try page fault" case.

People with old hardware are not likely to care about RDS anyway, and
the optimization for the 32-bit case is simply buggy, since it doesn't
verify the user addresses properly.

Reported-by: Dan Rosenberg <drosenberg@vsecurity.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-15 11:09:28 -07:00
David S. Miller e40051d134 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
	drivers/net/qlcnic/qlcnic_init.c
	net/ipv4/ip_output.c
2010-09-27 01:03:03 -07:00
Eric Dumazet f064af1e50 net: fix a lockdep splat
We have for each socket :

One spinlock (sk_slock.slock)
One rwlock (sk_callback_lock)

Possible scenarios are :

(A) (this is used in net/sunrpc/xprtsock.c)
read_lock(&sk->sk_callback_lock) (without blocking BH)
<BH>
spin_lock(&sk->sk_slock.slock);
...
read_lock(&sk->sk_callback_lock);
...

(B)
write_lock_bh(&sk->sk_callback_lock)
stuff
write_unlock_bh(&sk->sk_callback_lock)

(C)
spin_lock_bh(&sk->sk_slock)
...
write_lock_bh(&sk->sk_callback_lock)
stuff
write_unlock_bh(&sk->sk_callback_lock)
spin_unlock_bh(&sk->sk_slock)

This (C) case conflicts with (A) :

CPU1 [A]                         CPU2 [C]
read_lock(callback_lock)
<BH>                             spin_lock_bh(slock)
<wait to spin_lock(slock)>
                                 <wait to write_lock_bh(callback_lock)>

We have one problematic (C) use case in inet_csk_listen_stop() :

local_bh_disable();
bh_lock_sock(child); // spin_lock_bh(&sk->sk_slock)
WARN_ON(sock_owned_by_user(child));
...
sock_orphan(child); // write_lock_bh(&sk->sk_callback_lock)

lockdep is not happy with this, as reported by Tetsuo Handa

It seems only way to deal with this is to use read_lock_bh(callbacklock)
everywhere.

Thanks to Jarek for pointing a bug in my first attempt and suggesting
this solution.

Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Jarek Poplawski <jarkao2@gmail.com>
Tested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-09-24 22:26:10 -07:00
Dan Carpenter aef3ea33e8 rds: spin_lock_irq() is not nestable
This is basically just a cleanup.  IRQs were disabled on the previous
line so we don't need to do it again here.  In the current code IRQs
would get turned on one line earlier than intended.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-09-19 11:59:44 -07:00
Dan Carpenter f4fa7f3807 rds: double unlock in rds_ib_cm_handle_connect()
We unlock after we goto out.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-09-19 11:59:44 -07:00
Dan Carpenter 9b9d2e00bf rds: signedness bug
In the original code if the copy_from_user() fails in rds_rdma_pages()
then the error handling fails and we get a stack trace from kmalloc().

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-09-19 11:59:43 -07:00
Andy Grover 20c72bd5f5 RDS: Implement masked atomic operations
Add two CMSGs for masked versions of cswp and fadd. args
struct modified to use a union for different atomic op type's
arguments. Change IB to do masked atomic ops. Atomic op type
in rds_message similarly unionized.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:16:51 -07:00
Zach Brown 59f740a6ae RDS/IB: print string constants in more places
This prints the constant identifier for work completion status and rdma
cm event types, like we already do for IB event types.

A core string array helper is added that each string type uses.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:16:50 -07:00
Zach Brown 4518071ac1 RDS: cancel connection work structs as we shut down
Nothing was canceling the send and receive work that might have been
queued as a conn was being destroyed.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:16:49 -07:00
Zach Brown ffcec0e110 RDS: don't call rds_conn_shutdown() from rds_conn_destroy()
rds_conn_shutdown() can return before the connection is shut down when
it encounters an existing state that it doesn't understand.  This lets
rds_conn_destroy() then start tearing down the conn from under paths
that are still using it.

It's more reliable the shutdown work and wait for krdsd to complete the
shutdown callback.  This stopped some hangs I was seeing where krdsd was
trying to shut down a freed conn.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:16:48 -07:00
Zach Brown 5adb5bc65f RDS: have sockets get transport module references
Right now there's nothing to stop the various paths that use
rs->rs_transport from racing with rmmod and executing freed transport
code.  The simple fix is to have binding to a transport also hold a
reference to the transport's module, removing this class of races.

We already had an unused t_owner field which was set for the modular
transports and which wasn't set for the built-in loop transport.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:16:47 -07:00
Zach Brown 77510481c0 RDS: remove old rs_transport comment
rs_transport is now also used by the rdma paths once the socket is
bound.  We don't need this stale comment to tell us what cscope can.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:16:46 -07:00
Zach Brown fe8ff6b58f RDS: lock rds_conn_count decrement in rds_conn_destroy()
rds_conn_destroy() can race with all other modifications of the
rds_conn_count but it was modifying the count without locking.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:16:45 -07:00
Zach Brown ea819867b7 RDS/IB: protect the list of IB devices
The RDS IB device list wasn't protected by any locking.  Traversal in
both the get_mr and FMR flushing paths could race with additon and
removal.

List manipulation is done with RCU primatives and is protected by the
write side of a rwsem.  The list traversal in the get_mr fast path is
protected by a rcu read critical section.  The FMR list traversal is
more problematic because it can block while traversing the list.  We
protect this with the read side of the rwsem.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:16:44 -07:00
Zach Brown 1bde04a63d RDS/IB: print IB event strings as well as their number
It's nice to not have to go digging in the code to see which event
occurred.  It's easy to throw together a quick array that maps the ib
event enums to their strings.  I didn't see anything in the stack that
does this translation for us, but I also didn't look very hard.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:16:43 -07:00
Chris Mason 8576f374ac RDS: flush fmrs before allocating new ones
Flushing FMRs is somewhat expensive, and is currently kicked off when
the interrupt handler notices that we are getting low.  The result of
this is that FMR flushing only happens from the interrupt cpus.

This spreads the load more effectively by triggering flushes just before
we allocate a new FMR.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-09-08 18:16:42 -07:00
Chris Mason b4e1da3c9a RDS: properly use sg_init_table
This is only needed to keep debugging code from bugging.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-09-08 18:16:41 -07:00
Zach Brown f046011cd7 RDS/IB: track signaled sends
We're seeing bugs today where IB connection shutdown clears the send
ring while the tasklet is processing completed sends.  Implementation
details cause this to dereference a null pointer.  Shutdown needs to
wait for send completion to stop before tearing down the connection.  We
can't simply wait for the ring to empty because it may contain
unsignaled sends that will never be processed.

This patch tracks the number of signaled sends that we've posted and
waits for them to complete.  It also makes sure that the tasklet has
finished executing.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:16:40 -07:00
Zach Brown ef87b7ea39 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>
2010-09-08 18:16:39 -07:00
Andy Grover c20f5b9633 RDS/IB: Use SLAB_HWCACHE_ALIGN flag for kmem_cache_create()
We are *definitely* counting cycles as closely as DaveM, so
ensure hwcache alignment for our recv ring control structs.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:16:38 -07:00
Zach Brown d455ab6409 RDS/IB: always process recv completions
The recv refill path was leaking fragments because the recv event handler had
marked a ring element as free without freeing its frag.  This was happening
because it wasn't processing receives when the conn wasn't marked up or
connecting, as can be the case if it races with rmmod.

Two observations support always processing receives in the callback.

First, buildup should only post receives, thus triggering recv event handler
calls, once it has built up all the state to handle them.  Teardown should
destroy the CQ and drain the ring before tearing down the state needed to
process recvs.  Both appear to be true today.

Second, this test was fundamentally racy.  There is nothing to stop rmmod and
connection destruction from swooping in the moment after the conn state was
sampled but before real receive procesing starts.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:16:36 -07:00
Zach Brown 80c51be56f RDS: return to a single-threaded krdsd
We were seeing very nasty bugs due to fundamental assumption the current code
makes about concurrent work struct processing.  The code simpy isn't able to
handle concurrent connection shutdown work function execution today, for
example, which is very much possible once a multi-threaded krdsd was
introduced.  The problem compounds as additional work structs are added to the
mix.

krdsd is no longer perforance critical now that send and receive posting and
FMR flushing are done elsewhere, so the safest fix is to move back to the
single threaded krdsd that the current code was built around.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:16:35 -07:00
Zach Brown 515e079dab RDS/IB: create a work queue for FMR flushing
This patch moves the FMR flushing work in to its own mult-threaded work queue.
This is to maintain performance in preparation for returning the main krdsd
work queue back to a single threaded work queue to avoid deep-rooted
concurrency bugs.

This is also good because it further separates FMRs, which might be removed
some day, from the rest of the code base.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:16:34 -07:00
Zach Brown 8aeb1ba663 RDS/IB: destroy connections on rmmod
IB connections were not being destroyed during rmmod.

First, recently IB device removal callback was changed to disconnect
connections that used the removing device rather than destroying them.  So
connections with devices during rmmod were not being destroyed.

Second, rds_ib_destroy_nodev_conns() was being called before connections are
disassociated with devices.  It would almost never find connections in the
nodev list.

We first get rid of rds_ib_destroy_conns(), which is no longer called, and
refactor the existing caller into the main body of the function and get rid of
the list and lock wrappers.

Then we call rds_ib_destroy_nodev_conns() *after* ib_unregister_client() has
removed the IB device from all the conns and put the conns on the nodev list.

The result is that IB connections are destroyed by rmmod.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:16:33 -07:00
Zach Brown 24fa163a4b RDS/IB: wait for IB dev freeing work to finish during rmmod
The RDS IB client removal callback can queue work to drop the final reference
to an IB device.  We have to make sure that this function has returned before
we complete rmmod or the work threads can try to execute freed code.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:16:32 -07:00
Andy Grover b6fb0df12d RDS/IB: Make ib_recv_refill return void
Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:16:31 -07:00
Andy Grover fbf4d7e3d0 RDS: Remove unused XLIST_PTR_TAIL and xlist_protect()
Not used.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:16:06 -07:00
Andy Grover c9455d9996 RDS: whitespace 2010-09-08 18:15:32 -07:00
Chris Mason 7a0ff5dbdd RDS: use delayed work for the FMR flushes
Using a delayed work queue helps us make sure a healthy number of FMRs
have queued up over the limit.  It makes for a large improvement in RDMA
iops.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-09-08 18:15:30 -07:00
Chris Mason eabb732279 rds: more FMRs are faster
When we add more FMRs, we flush them less often and so we go faster.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-09-08 18:15:29 -07:00
Chris Mason 6fa70da608 rds: recycle FMRs through lockless lists
FRM allocation and recycling is performance critical and fairly lock
intensive.  The current code has a per connection lock that all
processes bang on and it becomes a major bottleneck on large systems.

This changes things to use a number of cmpxchg based lists instead,
allowing us to go through the whole FMR lifecycle without locking inside
RDS.

Zach Brown pointed out that our usage of cmpxchg for xlist removal is
racey if someone manages to remove and add back an FMR struct into the list
while another CPU can see the FMR's address at the head of the list.

The second CPU might assume the list hasn't changed when in fact any
number of operations might have happened in between the deletion and
reinsertion.

This commit maintains a per cpu count of CPUs that are currently
in xlist removal, and establishes a grace period to make sure that
nobody can see an entry we have just removed from the list.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-09-08 18:15:28 -07:00
Zach Brown 0f4b1c7e89 rds: fix rds_send_xmit() serialization
rds_send_xmit() was changed to hold an interrupt masking spinlock instead of a
mutex so that it could be called from the IB receive tasklet path.  This broke
the TCP transport because its xmit method can block and masks and unmasks
interrupts.

This patch serializes callers to rds_send_xmit() with a simple bit instead of
the current spinlock or previous mutex.  This enables rds_send_xmit() to be
called from any context and to call functions which block.  Getting rid of the
c_send_lock exposes the bare c_lock acquisitions which are changed to block
interrupts.

A waitqueue is added so that rds_conn_shutdown() can wait for callers to leave
rds_send_xmit() before tearing down partial send state.  This lets us get rid
of c_senders.

rds_send_xmit() is changed to check the conn state after acquiring the
RDS_IN_XMIT bit to resolve races with the shutdown path.  Previously both
worked with the conn state and then the lock in the same order, allowing them
to race and execute the paths concurrently.

rds_send_reset() isn't racing with rds_send_xmit() now that rds_conn_shutdown()
properly ensures that rds_send_xmit() can't start once the conn state has been
changed.  We can remove its previous use of the spinlock.

Finally, c_send_generation is redundant.  Callers can race to test the c_flags
bit by simply retrying instead of racing to test the c_send_generation atomic.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:15:27 -07:00
Zach Brown 501dcccdb7 rds: block ints when acquiring c_lock in rds_conn_message_info()
conn->c_lock is acquired in interrupt context.  rds_conn_message_info() is
called from user context and was acquiring c_lock without blocking interrupts,
leading to possible deadlocks.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:15:26 -07:00
Zach Brown 671202f349 rds: remove unused rds_send_acked_before()
rds_send_acked_before() wasn't blocking interrupts when acquiring c_lock from
user context but nothing calls it.  Rather than fix its use of c_lock we just
remove the function.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:15:25 -07:00
Chris Mason 037f18a307 RDS: use friendly gfp masks for prefill
When prefilling the rds frags, we end up doing a lot of allocations.
We're not in atomic context here, and so there's no reason to dip into
atomic reserves.  This changes the prefills to use masks that allow
waiting.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-09-08 18:15:24 -07:00
Chris Mason 3324412587 RDS/IB: Add caching of frags and incs
This patch is based heavily on an initial patch by Chris Mason.
Instead of freeing slab memory and pages, it keeps them, and
funnels them back to be reused.

The lock minimization strategy uses xchg and cmpxchg atomic ops
for manipulation of pointers to list heads. We anchor the lists with a
pointer to a list_head struct instead of a static list_head struct.
We just have to carefully use the existing primitives with
the difference between a pointer and a static head struct.

For example, 'list_empty()' means that our anchor pointer points to a list with
a single item instead of meaning that our static head element doesn't point to
any list items.

Original patch by Chris, with significant mods and fixes by Andy and Zach.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:15:23 -07:00
Andy Grover fc24f78085 RDS/IB: Remove ib_recv_unmap_page()
All it does is call unmap_sg(), so just call that directly.

The comment above unmap_page also may be incorrect, so we
shouldn't hold on to it, either.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:15:22 -07:00
Andy Grover 3427e854e1 RDS: Assume recv->r_frag is always NULL in refill_one()
refill_one() should never be called on a recv struct that
doesn't need a new r_frag allocated. Add a WARN and remove
conditional around r_frag alloc code.

Also, add a comment to explain why r_ibinc may or may not
need refilling.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:15:21 -07:00
Andy Grover 0b088e003c RDS: Use page_remainder_alloc() for recv bufs
Instead of splitting up a page into RDS_FRAG_SIZE chunks
ourselves, ask rds_page_remainder_alloc() to do it. While it
is possible PAGE_SIZE > FRAG_SIZE, on x86en it isn't, so having
duplicate "carve up a page into buffers" code seems excessive.

The other modification this spawns is the use of a single
struct scatterlist in rds_page_frag instead of a bare page ptr.
This causes verbosity to increase in some places, and decrease
in others.

Finally, I decided to unify the lifetimes and alloc/free of
rds_page_frag and its page. This is a nice simplification in itself,
but will be extra-nice once we come to adding cmason's recycling
patch.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:15:20 -07:00
Zach Brown fc19de38be RDS/IB: disconnect when IB devices are removed
Currently IB device removal destroys connections which are associated with the
device.  This prevents connections from being re-established when replacement
devices are added.

Instead we'll queue shutdown work on the connections as their devices are
removed.  When we see that devices are added we triger connection attempts on
all connections that don't currently have a device.

The result is that RDS sockets can resume device-independent work (bcopy, not
RDMA) across IB device removal and restoration.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:15:19 -07:00
Zach Brown f3c6808d3d RDS: introduce rds_conn_connect_if_down()
A few paths had the same block of code to queue a connection's connect work if
it was in the right state.  Let's move this in to a helper function.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:15:18 -07:00
Zach Brown 3e0249f9c0 RDS/IB: add refcount tracking to struct rds_ib_device
The RDS IB client .remove callback used to free the rds_ibdev for the given
device unconditionally.  This could race other users of the struct.  This patch
adds refcounting so that we only free the rds_ibdev once all of its users are
done.

Many rds_ibdev users are tied to connections.  We give the connection a
reference and change these users to reference the device in the connection
instead of looking it up in the IB client data.  The only user of the IB client
data remaining is the first lookup of the device as connections are built up.

Incrementing the reference count of a device found in the IB client data could
race with final freeing so we use an RCU grace period to make sure that freeing
won't happen until those lookups are done.

MRs need the rds_ibdev to get at the pool that they're freed in to.  They exist
outside a connection and many MRs can reference different devices from one
socket, so it was natural to have each MR hold a reference.  MR refs can be
dropped from interrupt handlers and final device teardown can block so we push
it off to a work struct.  Pool teardown had to be fixed to cancel its pending
work instead of deadlocking waiting for all queued work, including itself, to
finish.

MRs get their reference from the global device list, which gets a reference.
It is left unprotected by locks and remains racy.  A simple global lock would
be a significant bottleneck.  More scalable (complicated) locking should be
done carefully in a later patch.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:15:17 -07:00
Zach Brown 89bf9d4158 RDS/IB: get the xmit max_sge from the RDS IB device on the connection
rds_ib_xmit_rdma() was calling ib_get_client_data() to get at the rds_ibdevice
just to get the max_sge for the transmit.  This patch instead has it get it
directly off the rds_ibdev which is stored on the connection.

The current code won't free the rds_ibdev until all the IB connections that use
it are freed.  So it's safe to reference the rds_ibdev this way.  In the future
it also makes it easier to support proper reference counting of the rds_ibdev
struct.

As an additional bonus, this gets rid of the performance hit of calling in to
the IB stack to look up the rds_ibdev.  The current implementation in the IB
stack acquires an interrupt blocking spinlock to protect the registration of
client callback data.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:15:16 -07:00
Zach Brown a46ca94e7f RDS/IB: rds_ib_cm_handle_connect() forgot to unlock c_cm_lock
rds_ib_cm_handle_connect() could return without unlocking the c_conn_lock if
rds_setup_qp() failed.  Rather than adding another imbalanced mutex_unlock() to
this error path we only unlock the mutex once as we exit the function, reducing
the likelyhood of making this same mistake in the future.  We remove the
previous mulitple return sites, leaving one unambigious return path.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08 18:15:15 -07:00
Chris Mason 1cc2228c59 rds: Fix reference counting on the for xmit_atomic and xmit_rdma
This makes sure we have the proper number of references in
rds_ib_xmit_atomic and rds_ib_xmit_rdma.  We also consistently
drop references the same way for all message types as the IOs end.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-09-08 18:15:13 -07:00
Chris Mason bcf50ef2ce rds: use RCU to protect the connection hash
The connection hash was almost entirely RCU ready, this
just makes the final couple of changes to use RCU instead
of spinlocks for everything.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-09-08 18:15:12 -07:00
Chris Mason abf454398c RDS: use locking on the connection hash list
rds_conn_destroy really needs locking while it changes the
connection hash.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-09-08 18:15:11 -07:00
Chris Mason c9e65383a2 rds: Fix RDMA message reference counting
The RDS send_xmit code was trying to get fancy with message
counting and was dropping the final reference on the RDMA messages
too early.  This resulted in memory corruption and oopsen.

The fix here is to always add a ref as the parts of the message passes
through rds_send_xmit, and always drop a ref as the parts of the message
go through completion handling.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-09-08 18:15:10 -07:00
Chris Mason 7e3f2952ee rds: don't let RDS shutdown a connection while senders are present
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: Chris Mason <chris.mason@oracle.com>
2010-09-08 18:15:09 -07:00
Chris Mason 38a4e5e613 rds: Use RCU for the bind lookup searches
The RDS bind lookups are somewhat expensive in terms of CPU
time and locking overhead.  This commit changes them into a
faster RCU based hash tree instead of the rbtrees they were using
before.

On large NUMA systems it is a significant improvement.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-09-08 18:15:08 -07:00
Andy Grover e4c52c98e0 RDS/IB: add _to_node() macros for numa and use {k,v}malloc_node()
Allocate send/recv rings in memory that is node-local to the HCA.
This significantly helps performance.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:14:06 -07:00
Andy Grover 4a81802b5e RDS/IB: Remove unused variable in ib_remove_addr()
Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:29 -07:00
Chris Mason 764f2dd92f rds: rcu-ize rds_ib_get_device()
rds_ib_get_device is called very often as we turn an
ip address into a corresponding device structure.  It currently
take a global spinlock as it walks different lists to find active
devices.

This commit changes the lists over to RCU, which isn't very complex
because they are not updated very often at all.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-09-08 18:12:28 -07:00
Chris Mason c83188dcd7 rds: per-rm flush_wait waitq
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: Chris Mason <chris.mason@oracle.com>
2010-09-08 18:12:27 -07:00
Chris Mason 976673ee1b rds: switch to rwlock on bind_lock
The bind_lock is almost entirely readonly, but it gets
hammered during normal operations and is a major bottleneck.

This commit changes it to an rwlock, which takes it from 80%
of the system time on a big numa machine down to much lower
numbers.

A better fix would involve RCU, which is done in a later commit

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-09-08 18:12:26 -07:00
Andy Grover ce47f52f42 RDS: Update comments in rds_send_xmit()
Update comments to reflect changes in previous commit.

Keeping as separate commits due to different authorship.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:25 -07:00
Chris Mason 9e29db0e36 RDS: Use a generation counter to avoid rds_send_xmit loop
rds_send_xmit is required to loop around after it releases the lock
because someone else could done a trylock, found someone working on the
list and backed off.

But, once we drop our lock, it is possible that someone else does come
in and make progress on the list.  We should detect this and not loop
around if another process is actually working on the list.

This patch adds a generation counter that is bumped every time we
get the lock and do some send work.  If the retry notices someone else
has bumped the generation counter, it does not need to loop around and
continue working.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:24 -07:00
Andy Grover acfcd4d4ec RDS: Get pong working again
Call send_xmit() directly from pong()

Set pongs as op_active

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:23 -07:00
Andy Grover a40aa9233a RDS: Do wait_event_interruptible instead of wait_event
Can't see a reason not to allow signals to interrupt the wait.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:22 -07:00
Andy Grover fcc5450c63 RDS: Remove send_quota from send_xmit()
The purpose of the send quota was really to give fairness
when different connections were all using the same
workq thread to send backlogged msgs -- they could only send
so many before another connection could make progress.

Now that each connection is pushing the backlog from its
completion handler, they are all guaranteed to make progress
and the quota isn't needed any longer.

A thread *will* have to send all previously queued data, as well
as any further msgs placed on the queue while while c_send_lock
was held. In a pathological case a single process can get
roped into doing this for long periods while other threads
get off free. But, since it can only do this until the transport
reports full, this is a bounded scenario.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:21 -07:00
Andy Grover 51e2cba8b5 RDS: Move atomic stats from general to ib-specific area
Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:20 -07:00
Andy Grover ab1a6926f5 RDS: rds_message_unmapped() doesn't need to check if queue active
If the queue has nobody on it, then wake_up does nothing.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:19 -07:00
Andy Grover cf4b7389ee RDS: Fix locking in send on m_rs_lock
Do not nest m_rs_lock under c_lock

Disable interrupts in {rdma,atomic}_send_complete

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:18 -07:00
Andy Grover f2ec76f288 RDS: Use NOWAIT in message_map_pages()
Can no longer block, so use NOWAIT.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:17 -07:00
Andy Grover 2fa57129df RDS: Bypass workqueue when queueing cong updates
Now that rds_send_xmit() does not block, we can call it directly
instead of going through the helper thread.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:16 -07:00
Andy Grover a7d3a28148 RDS: Call rds_send_xmit() directly from sendmsg()
rds_sendmsg() is calling the send worker function to
send the just-queued datagrams, presumably because it wants
the behavior where anything not sent will re-call the send
worker. We now ensure all queued datagrams are sent by retrying
from the send completion handler, so this isn't needed any more.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:15 -07:00
Andy Grover 2ad8099b58 RDS: rds_send_xmit() locking/irq fixes
rds_message_put() cannot be called with irqs off, so move it after
irqs are re-enabled.

Spinlocks throughout the function do not to use _irqsave because
the lock of c_send_lock at top already disabled irqs.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:13 -07:00
Andy Grover 049ee3f500 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>
2010-09-08 18:12:12 -07:00
Andy Grover f17a1a55fb RDS: Refill recv ring directly from tasklet
Performance is better if we use allocations that don't block
to refill the receive ring. Since the whole reason we were
kicking out to the worker thread was so we could do blocking
allocs, we no longer need to do this.

Remove gfp params from rds_ib_recv_refill(); we always use
GFP_NOWAIT.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:11 -07:00
Andy Grover 77dd550e55 RDS: Stop supporting old cong map sending method
We now ask the transport to give us a rm for the congestion
map, and then we handle it normally. Previously, the
transport defined a function that we would call to send
a congestion map.

Convert TCP and loop transports to new cong map method.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:10 -07:00
Andy Grover e32b4a7049 RDS/IB: Do not wait for send ring to be empty on conn shutdown
Now that we are signaling send completions much less, we are likely
to have dirty entries in the send queue when the connection is
shut down (on rmmod, for example.) These are cleaned up a little
further down in conn_shutdown, but if we wait on the ring_empty_wait
for them, it'll never happen, and we hand on unload.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:09 -07:00
Andy Grover ff3d7d3613 RDS: Perform unmapping ops in stages
Previously, RDS would wait until the final send WR had completed
and then handle cleanup. With silent ops, we do not know
if an atomic, rdma, or data op will be last. This patch
handles any of these cases by keeping a pointer to the last
op in the message in m_last_op.

When the TX completion event fires, rds dispatches to per-op-type
cleanup functions, and then does whole-message cleanup, if the
last op equalled m_last_op.

This patch also moves towards having op-specific functions take
the op struct, instead of the overall rm struct.

rds_ib_connection has a pointer to keep track of a a partially-
completed data send operation. This patch changes it from an
rds_message pointer to the narrower rm_data_op pointer, and
modifies places that use this pointer as needed.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:08 -07:00
Andy Grover aa0a4ef4ac RDS: Make sure cmsgs aren't used in improper ways
It hasn't cropped up in the field, but this code ensures it is
impossible to issue operations that pass an rdma cookie (DEST, MAP)
in the same sendmsg call that's actually initiating rdma or atomic
ops.

Disallowing this perverse-but-technically-allowed usage makes silent
RDMA heuristics slightly easier.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:07 -07:00
Andy Grover 2c3a5f9abb RDS: Add flag for silent ops. Do atomic op before RDMA
Add a flag to the API so users can indicate they want
silent operations. This is needed because silent ops
cannot be used with USE_ONCE MRs, so we can't just
assume silent.

Also, change send_xmit to do atomic op before rdma op if
both are present, and centralize the hairy logic to determine if
we want to attempt silent, or not.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:06 -07:00
Andy Grover 7e3bd65ebf RDS: Move some variables around for consistency
Also, add a comment.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:05 -07:00
Andy Grover 940786eb0a RDS: queue failure notifications for dropped atomic ops
When dropping ops in the send queue, we notify the client
of failed rdma ops they asked for notifications on, but not
atomic ops. It should be for both.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:04 -07:00
Andy Grover ee4c7b47e4 RDS: Add a warning if trying to allocate 0 sgs
rds_message_alloc_sgs() only works when nents is nonzero.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:03 -07:00
Andy Grover 372cd7dedf RDS: Do not set op_active in r_m_copy_from_user().
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: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:02 -07:00
Andy Grover 5b2366bd28 RDS: Rewrite rds_send_xmit
Simplify rds_send_xmit().

Send a congestion map (via xmit_cong_map) without
decrementing send_quota.

Move resetting of conn xmit variables to end of loop.

Update comments.

Implement a special case to turn off sending an rds header
when there is an atomic op and no other data.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:01 -07:00
Andy Grover 6c7cc6e469 RDS: Rename data op members prefix from m_ to op_
For consistency.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:59 -07:00
Andy Grover f8b3aaf2ba RDS: Remove struct rds_rdma_op
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: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:58 -07:00
Andy Grover d0ab25a83c RDS: purge atomic resources too in rds_message_purge()
Add atomic_free_op function, analogous to rdma_free_op,
and call it in rds_message_purge().

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:57 -07:00
Andy Grover 4324879df0 RDS: Inline rdma_prepare into cmsg_rdma_args
cmsg_rdma_args just calls rdma_prepare and does a little
arg checking -- not quite enough to justify its existence.
Plus, it is the only caller of rdma_prepare().

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:56 -07:00
Andy Grover 241eef3e2f RDS: Implement silent atomics
Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:55 -07:00
Andy Grover d37c935905 RDS: Move loop-only function to loop.c
Also, try to better-document the locking around the
rm and its m_inc in loop.c.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:54 -07:00
Andy Grover c8de3f1005 RDS/IB: Make all flow control code conditional on i_flowctl
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: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:53 -07:00
Andy Grover 1d34f17571 RDS: Remove unsignaled_bytes sysctl
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: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:52 -07:00
Andy Grover da5a06cef5 RDS: rewrite rds_ib_xmit
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: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:51 -07:00
Andy Grover 919ced4ce7 RDS/IB: Remove ib_[header/data]_sge() functions
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: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:50 -07:00
Andy Grover 6f3d05db0d RDS/IB: Remove dead code
Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:49 -07:00
Andy Grover f147dd9eca RDS/IB: Disallow connections less than RDS 3.1
RDS 3.0 connections (in OFED 1.3 and earlier) put the
header at the end. 3.1 connections put it at the head.
The code has significant added complexity in order to
handle both configurations. In OFED 1.6 we can
drop this and simplify the code by only supporting
"header-first" configuration.

This patch checks the protocol version, and if prior
to 3.1, does not complete the connection.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:48 -07:00
Andy Grover 9c030391e8 RDS/IB: eliminate duplicate code
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: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:47 -07:00
Andy Grover 809fa148a2 RDS: inc_purge() transport function unused - remove it
Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:46 -07:00
Andy Grover 6200ed7799 RDS: Whitespace
Tidy up some whitespace issues.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:44 -07:00
Andy Grover d22faec22c RDS: Do not mask address when pinning pages
This does not appear to be necessary.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:43 -07:00