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vhost: add __rcu annotations

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Also add rcu_dereference_protected() for code paths where locks are held.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
This commit is contained in:
Arnd Bergmann
2010-03-09 19:24:45 +01:00
committed by Paul E. McKenney
parent 65e6bf484c
commit 28457ee69c
3 changed files with 35 additions and 13 deletions
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22
drivers/vhost/vhost.c
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@@ -284,7 +284,7 @@ long vhost_dev_reset_owner(struct vhost_dev *dev)
vhost_dev_cleanup(dev);
memory->nregions = 0;
dev->memory = memory;
RCU_INIT_POINTER(dev->memory, memory);
return 0;
}
@@ -316,8 +316,9 @@ void vhost_dev_cleanup(struct vhost_dev *dev)
fput(dev->log_file);
dev->log_file = NULL;
/* No one will access memory at this point */
kfree(dev->memory);
dev->memory = NULL;
kfree(rcu_dereference_protected(dev->memory,
lockdep_is_held(&dev->mutex)));
RCU_INIT_POINTER(dev->memory, NULL);
if (dev->mm)
mmput(dev->mm);
dev->mm = NULL;
@@ -401,14 +402,22 @@ static int vq_access_ok(unsigned int num,
/* Caller should have device mutex but not vq mutex */
int vhost_log_access_ok(struct vhost_dev *dev)
{
return memory_access_ok(dev, dev->memory, 1);
struct vhost_memory *mp;
mp = rcu_dereference_protected(dev->memory,
lockdep_is_held(&dev->mutex));
return memory_access_ok(dev, mp, 1);
}
/* Verify access for write logging. */
/* Caller should have vq mutex and device mutex */
static int vq_log_access_ok(struct vhost_virtqueue *vq, void __user *log_base)
{
return vq_memory_access_ok(log_base, vq->dev->memory,
struct vhost_memory *mp;
mp = rcu_dereference_protected(vq->dev->memory,
lockdep_is_held(&vq->mutex));
return vq_memory_access_ok(log_base, mp,
vhost_has_feature(vq->dev, VHOST_F_LOG_ALL)) &&
(!vq->log_used || log_access_ok(log_base, vq->log_addr,
sizeof *vq->used +
@@ -448,7 +457,8 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
kfree(newmem);
return -EFAULT;
}
oldmem = d->memory;
oldmem = rcu_dereference_protected(d->memory,
lockdep_is_held(&d->mutex));
rcu_assign_pointer(d->memory, newmem);
synchronize_rcu();
kfree(oldmem);