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vhost: do not take lock on owner reset

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A deadlock happens when handling VHOST_USER_RESET_OWNER request
for the same reason the lock is not taken for
VHOST_USER_GET_VRING_BASE.

It is safe not to take the lock, as the queues are no more used
by the application when the virtqueues and the device are reset.

Fixes: a3688046995f ("vhost: protect active rings from async ring changes")
Cc: stable@dpdk.org

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: Tiwei Bie <tiwei.bie@intel.com>
Reviewed-by: Jianfeng Tan <jianfeng.tan@intel.com>
This commit is contained in:
Maxime Coquelin 2018-02-12 16:46:12 +01:00 committed by Thomas Monjalon
parent 4785747066
commit 9fce5d0b40
1 changed files with 5 additions and 5 deletions
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10
lib/librte_vhost/vhost_user.c
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@ -1348,16 +1348,16 @@ vhost_user_msg_handler(int vid, int fd)
}
/*
* Note: we don't lock all queues on VHOST_USER_GET_VRING_BASE,
* since it is sent when virtio stops and device is destroyed.
* destroy_device waits for queues to be inactive, so it is safe.
* Otherwise taking the access_lock would cause a dead lock.
* Note: we don't lock all queues on VHOST_USER_GET_VRING_BASE
* and VHOST_USER_RESET_OWNER, since it is sent when virtio stops
* and device is destroyed. destroy_device waits for queues to be
* inactive, so it is safe. Otherwise taking the access_lock
* would cause a dead lock.
*/
switch (msg.request.master) {
case VHOST_USER_SET_FEATURES:
case VHOST_USER_SET_PROTOCOL_FEATURES:
case VHOST_USER_SET_OWNER:
case VHOST_USER_RESET_OWNER:
case VHOST_USER_SET_MEM_TABLE:
case VHOST_USER_SET_LOG_BASE:
case VHOST_USER_SET_LOG_FD: