linux-stable.git/drivers/vhost/vhost.c, branch v3.19

vhost: relax used address alignment

2014-12-29T08:55:06+00:00

virtio 1.0 only requires used address to be 4 byte aligned,
vhost required 8 bytes (size of vring_used_elem).
Fix up vhost to match that.

Additionally, while vhost correctly requires 8 byte
alignment for log, it's unconnected to used ring:
it's a consequence that log has u64 entries.
Tweak code to make that clearer.

Signed-off-by: Michael S. Tsirkin

vhost: virtio 1.0 endian-ness support

2014-12-09T10:05:29+00:00

Signed-off-by: Michael S. Tsirkin

vhost: switch to get/put_user exclusively

2014-12-09T10:05:29+00:00

Most places in vhost can use __get/__put_user rather than
get/put_user since addresses are pre-validated.
This should be good for performance, but this also
will help make code sparse-clean: get/put_user macros
don't play well with __virtioXX bitwise tags.
Switch to get/put_user to __ variants everywhere in vhost.
There's one exception - for consistency switch that
as well, and add an explicit access_ok check.

Signed-off-by: Michael S. Tsirkin

vhost: move memory pointer to VQs

2014-06-09T13:21:07+00:00

commit 2ae76693b8bcabf370b981cd00c36cd41d33fabc
    vhost: replace rcu with mutex
replaced rcu sync for memory accesses with VQ mutex locl/unlock.
This is correct since all accesses are under VQ mutex, but incomplete:
we still do useless rcu lock/unlock operations, someone might copy this
code into some other context where this won't be right.
This use of RCU is also non standard and hard to understand.
Let's copy the pointer to each VQ structure, this way
the access rules become straight-forward, and there's
no need for RCU anymore.

Reported-by: Eric Dumazet 
Signed-off-by: Michael S. Tsirkin

vhost: move acked_features to VQs

2014-06-09T13:21:06+00:00

Refactor code to make sure features are only accessed
under VQ mutex. This makes everything simpler, no need
for RCU here anymore.

Signed-off-by: Michael S. Tsirkin

vhost: replace rcu with mutex

2014-06-09T13:21:06+00:00

All memory accesses are done under some VQ mutex.
So lock/unlock all VQs is a faster equivalent of synchronize_rcu()
for memory access changes.
Some guests cause a lot of these changes, so it's helpful
to make them faster.

Reported-by: "Gonglei (Arei)" 
Signed-off-by: Michael S. Tsirkin

vhost: remove the dead branch

2013-12-06T20:22:05+00:00

Since vhost_dev_init() forever return 0, some branches are never run,
therefore need to be removed.

Signed-off-by: Zhi Yong Wu 
Acked-by: Michael S. Tsirkin 
Signed-off-by: David S. Miller

vhost: wake up worker outside spin_lock

2013-09-17T06:21:32+00:00

the wake_up_process func is included by spin_lock/unlock in
vhost_work_queue,
but it could be done outside the spin_lock.
I have test it with kernel 3.0.27 and guest suse11-sp2 using iperf,
the num as below.
                  original                 modified
thread_num  tp(Gbps)   vhost(%)  |  tp(Gbps)     vhost(%)
1           9.59        28.82    |   9.59        27.49
8           9.61        32.92    |   9.62        26.77
64          9.58        46.48    |   9.55        38.99
256         9.6         63.7     |   9.6         52.59

Signed-off-by: Chuanyu Qin 
Signed-off-by: Michael S. Tsirkin

vhost: switch to use vhost_add_used_n()

2013-09-04T02:46:57+00:00

Let vhost_add_used() to use vhost_add_used_n() to reduce the code
duplication. To avoid the overhead brought by __copy_to_user(). We will use
put_user() when one used need to be added.

Signed-off-by: Jason Wang 
Signed-off-by: David S. Miller

vhost: Include linux/uio.h instead of linux/socket.h

2013-08-20T22:05:04+00:00

memcpy_fromiovec is moved from net/core/iovec.c to lib/iovec.c.
linux/uio.h provides the declaration for memcpy_fromiovec.

Include linux/uio.h instead of inux/socket.h for it.

Signed-off-by: Asias He 
Acked-by: Michael S. Tsirkin 
Signed-off-by: David S. Miller