]> bbs.cooldavid.org Git - net-next-2.6.git/blobdiff - drivers/vhost/vhost.c
scm: lower SCM_MAX_FD
[net-next-2.6.git] / drivers / vhost / vhost.c
index e05557d529992ec4deb1827a32574043bcd00925..94701ff3a23ad957a9c675bd3ccd74418c2f989e 100644 (file)
@@ -60,22 +60,25 @@ static int vhost_poll_wakeup(wait_queue_t *wait, unsigned mode, int sync,
        return 0;
 }
 
+static void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn)
+{
+       INIT_LIST_HEAD(&work->node);
+       work->fn = fn;
+       init_waitqueue_head(&work->done);
+       work->flushing = 0;
+       work->queue_seq = work->done_seq = 0;
+}
+
 /* Init poll structure */
 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
                     unsigned long mask, struct vhost_dev *dev)
 {
-       struct vhost_work *work = &poll->work;
-
        init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
        init_poll_funcptr(&poll->table, vhost_poll_func);
        poll->mask = mask;
        poll->dev = dev;
 
-       INIT_LIST_HEAD(&work->node);
-       work->fn = fn;
-       init_waitqueue_head(&work->done);
-       work->flushing = 0;
-       work->queue_seq = work->done_seq = 0;
+       vhost_work_init(&poll->work, fn);
 }
 
 /* Start polling a file. We add ourselves to file's wait queue. The caller must
@@ -95,35 +98,38 @@ void vhost_poll_stop(struct vhost_poll *poll)
        remove_wait_queue(poll->wqh, &poll->wait);
 }
 
-/* Flush any work that has been scheduled. When calling this, don't hold any
- * locks that are also used by the callback. */
-void vhost_poll_flush(struct vhost_poll *poll)
+static void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work)
 {
-       struct vhost_work *work = &poll->work;
        unsigned seq;
        int left;
        int flushing;
 
-       spin_lock_irq(&poll->dev->work_lock);
+       spin_lock_irq(&dev->work_lock);
        seq = work->queue_seq;
        work->flushing++;
-       spin_unlock_irq(&poll->dev->work_lock);
+       spin_unlock_irq(&dev->work_lock);
        wait_event(work->done, ({
-                  spin_lock_irq(&poll->dev->work_lock);
+                  spin_lock_irq(&dev->work_lock);
                   left = seq - work->done_seq <= 0;
-                  spin_unlock_irq(&poll->dev->work_lock);
+                  spin_unlock_irq(&dev->work_lock);
                   left;
        }));
-       spin_lock_irq(&poll->dev->work_lock);
+       spin_lock_irq(&dev->work_lock);
        flushing = --work->flushing;
-       spin_unlock_irq(&poll->dev->work_lock);
+       spin_unlock_irq(&dev->work_lock);
        BUG_ON(flushing < 0);
 }
 
-void vhost_poll_queue(struct vhost_poll *poll)
+/* Flush any work that has been scheduled. When calling this, don't hold any
+ * locks that are also used by the callback. */
+void vhost_poll_flush(struct vhost_poll *poll)
+{
+       vhost_work_flush(poll->dev, &poll->work);
+}
+
+static inline void vhost_work_queue(struct vhost_dev *dev,
+                                   struct vhost_work *work)
 {
-       struct vhost_dev *dev = poll->dev;
-       struct vhost_work *work = &poll->work;
        unsigned long flags;
 
        spin_lock_irqsave(&dev->work_lock, flags);
@@ -135,6 +141,11 @@ void vhost_poll_queue(struct vhost_poll *poll)
        spin_unlock_irqrestore(&dev->work_lock, flags);
 }
 
+void vhost_poll_queue(struct vhost_poll *poll)
+{
+       vhost_work_queue(poll->dev, &poll->work);
+}
+
 static void vhost_vq_reset(struct vhost_dev *dev,
                           struct vhost_virtqueue *vq)
 {
@@ -201,6 +212,45 @@ static int vhost_worker(void *data)
        }
 }
 
+/* Helper to allocate iovec buffers for all vqs. */
+static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
+{
+       int i;
+       for (i = 0; i < dev->nvqs; ++i) {
+               dev->vqs[i].indirect = kmalloc(sizeof *dev->vqs[i].indirect *
+                                              UIO_MAXIOV, GFP_KERNEL);
+               dev->vqs[i].log = kmalloc(sizeof *dev->vqs[i].log * UIO_MAXIOV,
+                                         GFP_KERNEL);
+               dev->vqs[i].heads = kmalloc(sizeof *dev->vqs[i].heads *
+                                           UIO_MAXIOV, GFP_KERNEL);
+
+               if (!dev->vqs[i].indirect || !dev->vqs[i].log ||
+                       !dev->vqs[i].heads)
+                       goto err_nomem;
+       }
+       return 0;
+err_nomem:
+       for (; i >= 0; --i) {
+               kfree(dev->vqs[i].indirect);
+               kfree(dev->vqs[i].log);
+               kfree(dev->vqs[i].heads);
+       }
+       return -ENOMEM;
+}
+
+static void vhost_dev_free_iovecs(struct vhost_dev *dev)
+{
+       int i;
+       for (i = 0; i < dev->nvqs; ++i) {
+               kfree(dev->vqs[i].indirect);
+               dev->vqs[i].indirect = NULL;
+               kfree(dev->vqs[i].log);
+               dev->vqs[i].log = NULL;
+               kfree(dev->vqs[i].heads);
+               dev->vqs[i].heads = NULL;
+       }
+}
+
 long vhost_dev_init(struct vhost_dev *dev,
                    struct vhost_virtqueue *vqs, int nvqs)
 {
@@ -218,6 +268,9 @@ long vhost_dev_init(struct vhost_dev *dev,
        dev->worker = NULL;
 
        for (i = 0; i < dev->nvqs; ++i) {
+               dev->vqs[i].log = NULL;
+               dev->vqs[i].indirect = NULL;
+               dev->vqs[i].heads = NULL;
                dev->vqs[i].dev = dev;
                mutex_init(&dev->vqs[i].mutex);
                vhost_vq_reset(dev, dev->vqs + i);
@@ -236,6 +289,29 @@ long vhost_dev_check_owner(struct vhost_dev *dev)
        return dev->mm == current->mm ? 0 : -EPERM;
 }
 
+struct vhost_attach_cgroups_struct {
+        struct vhost_work work;
+        struct task_struct *owner;
+        int ret;
+};
+
+static void vhost_attach_cgroups_work(struct vhost_work *work)
+{
+        struct vhost_attach_cgroups_struct *s;
+        s = container_of(work, struct vhost_attach_cgroups_struct, work);
+        s->ret = cgroup_attach_task_all(s->owner, current);
+}
+
+static int vhost_attach_cgroups(struct vhost_dev *dev)
+{
+        struct vhost_attach_cgroups_struct attach;
+        attach.owner = current;
+        vhost_work_init(&attach.work, vhost_attach_cgroups_work);
+        vhost_work_queue(dev, &attach.work);
+        vhost_work_flush(dev, &attach.work);
+        return attach.ret;
+}
+
 /* Caller should have device mutex */
 static long vhost_dev_set_owner(struct vhost_dev *dev)
 {
@@ -255,14 +331,20 @@ static long vhost_dev_set_owner(struct vhost_dev *dev)
        }
 
        dev->worker = worker;
-       err = cgroup_attach_task_current_cg(worker);
+       wake_up_process(worker);        /* avoid contributing to loadavg */
+
+       err = vhost_attach_cgroups(dev);
+       if (err)
+               goto err_cgroup;
+
+       err = vhost_dev_alloc_iovecs(dev);
        if (err)
                goto err_cgroup;
-       wake_up_process(worker);        /* avoid contributing to loadavg */
 
        return 0;
 err_cgroup:
        kthread_stop(worker);
+       dev->worker = NULL;
 err_worker:
        if (dev->mm)
                mmput(dev->mm);
@@ -284,7 +366,7 @@ 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;
 }
 
@@ -309,6 +391,7 @@ void vhost_dev_cleanup(struct vhost_dev *dev)
                        fput(dev->vqs[i].call);
                vhost_vq_reset(dev, dev->vqs + i);
        }
+       vhost_dev_free_iovecs(dev);
        if (dev->log_ctx)
                eventfd_ctx_put(dev->log_ctx);
        dev->log_ctx = NULL;
@@ -316,14 +399,18 @@ 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;
 
        WARN_ON(!list_empty(&dev->work_list));
-       kthread_stop(dev->worker);
+       if (dev->worker) {
+               kthread_stop(dev->worker);
+               dev->worker = NULL;
+       }
 }
 
 static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
@@ -332,7 +419,7 @@ static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
        /* Make sure 64 bit math will not overflow. */
        if (a > ULONG_MAX - (unsigned long)log_base ||
            a + (unsigned long)log_base > ULONG_MAX)
-               return -EFAULT;
+               return 0;
 
        return access_ok(VERIFY_WRITE, log_base + a,
                         (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
@@ -401,14 +488,22 @@ 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 +543,8 @@ 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);
@@ -819,11 +915,12 @@ int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
                if (r < 0)
                        return r;
                len -= l;
-               if (!len)
+               if (!len) {
+                       if (vq->log_ctx)
+                               eventfd_signal(vq->log_ctx, 1);
                        return 0;
+               }
        }
-       if (vq->log_ctx)
-               eventfd_signal(vq->log_ctx, 1);
        /* Length written exceeds what we have stored. This is a bug. */
        BUG();
        return 0;
@@ -907,7 +1004,7 @@ static int get_indirect(struct vhost_dev *dev, struct vhost_virtqueue *vq,
        }
 
        ret = translate_desc(dev, indirect->addr, indirect->len, vq->indirect,
-                            ARRAY_SIZE(vq->indirect));
+                            UIO_MAXIOV);
        if (unlikely(ret < 0)) {
                vq_err(vq, "Translation failure %d in indirect.\n", ret);
                return ret;