Merge tag 'for-4.5' of git://git.osdn.jp/gitroot/uclinux-h8/linux

[deliverable/linux.git] / drivers / hv / hv_utils_transport.c

diff --git a/drivers/hv/hv_utils_transport.c b/drivers/hv/hv_utils_transport.c
index 40abe44fcd984b7d9cd2e5631a2e09bd1a5eb162..4f42c0e20c20fd12f6de24d4490fb23952b7ed79 100644 (file)
--- a/drivers/hv/hv_utils_transport.c
+++ b/drivers/hv/hv_utils_transport.c
@@ -27,11 +27,9 @@ static struct list_head hvt_list = LIST_HEAD_INIT(hvt_list);
 
 static void hvt_reset(struct hvutil_transport *hvt)
 {
-       mutex_lock(&hvt->outmsg_lock);
        kfree(hvt->outmsg);
        hvt->outmsg = NULL;
        hvt->outmsg_len = 0;
-       mutex_unlock(&hvt->outmsg_lock);
        if (hvt->on_reset)
                hvt->on_reset();
 }
@@ -44,10 +42,17 @@ static ssize_t hvt_op_read(struct file *file, char __user *buf,
 
        hvt = container_of(file->f_op, struct hvutil_transport, fops);
 
-       if (wait_event_interruptible(hvt->outmsg_q, hvt->outmsg_len > 0))
+       if (wait_event_interruptible(hvt->outmsg_q, hvt->outmsg_len > 0 ||
+                                    hvt->mode != HVUTIL_TRANSPORT_CHARDEV))
                return -EINTR;
 
-       mutex_lock(&hvt->outmsg_lock);
+       mutex_lock(&hvt->lock);
+
+       if (hvt->mode == HVUTIL_TRANSPORT_DESTROY) {
+               ret = -EBADF;
+               goto out_unlock;
+       }
+
        if (!hvt->outmsg) {
                ret = -EAGAIN;
                goto out_unlock;
@@ -68,7 +73,7 @@ static ssize_t hvt_op_read(struct file *file, char __user *buf,
        hvt->outmsg_len = 0;
 
 out_unlock:
-       mutex_unlock(&hvt->outmsg_lock);
+       mutex_unlock(&hvt->lock);
        return ret;
 }
 
@@ -85,7 +90,10 @@ static ssize_t hvt_op_write(struct file *file, const char __user *buf,
        if (IS_ERR(inmsg))
                return PTR_ERR(inmsg);
 
-       ret = hvt->on_msg(inmsg, count);
+       if (hvt->mode == HVUTIL_TRANSPORT_DESTROY)
+               ret = -EBADF;
+       else
+               ret = hvt->on_msg(inmsg, count);
 
        kfree(inmsg);
 
@@ -99,6 +107,10 @@ static unsigned int hvt_op_poll(struct file *file, poll_table *wait)
        hvt = container_of(file->f_op, struct hvutil_transport, fops);
 
        poll_wait(file, &hvt->outmsg_q, wait);
+
+       if (hvt->mode == HVUTIL_TRANSPORT_DESTROY)
+               return POLLERR | POLLHUP;
+
        if (hvt->outmsg_len > 0)
                return POLLIN | POLLRDNORM;
 
@@ -108,40 +120,68 @@ static unsigned int hvt_op_poll(struct file *file, poll_table *wait)
 static int hvt_op_open(struct inode *inode, struct file *file)
 {
        struct hvutil_transport *hvt;
+       int ret = 0;
+       bool issue_reset = false;
 
        hvt = container_of(file->f_op, struct hvutil_transport, fops);
 
-       /*
-        * Switching to CHARDEV mode. We switch bach to INIT when device
-        * gets released.
-        */
-       if (hvt->mode == HVUTIL_TRANSPORT_INIT)
+       mutex_lock(&hvt->lock);
+
+       if (hvt->mode == HVUTIL_TRANSPORT_DESTROY) {
+               ret = -EBADF;
+       } else if (hvt->mode == HVUTIL_TRANSPORT_INIT) {
+               /*
+                * Switching to CHARDEV mode. We switch bach to INIT when
+                * device gets released.
+                */
                hvt->mode = HVUTIL_TRANSPORT_CHARDEV;
+       }
        else if (hvt->mode == HVUTIL_TRANSPORT_NETLINK) {
                /*
                 * We're switching from netlink communication to using char
                 * device. Issue the reset first.
                 */
-               hvt_reset(hvt);
+               issue_reset = true;
                hvt->mode = HVUTIL_TRANSPORT_CHARDEV;
-       } else
-               return -EBUSY;
+       } else {
+               ret = -EBUSY;
+       }
 
-       return 0;
+       if (issue_reset)
+               hvt_reset(hvt);
+
+       mutex_unlock(&hvt->lock);
+
+       return ret;
+}
+
+static void hvt_transport_free(struct hvutil_transport *hvt)
+{
+       misc_deregister(&hvt->mdev);
+       kfree(hvt->outmsg);
+       kfree(hvt);
 }
 
 static int hvt_op_release(struct inode *inode, struct file *file)
 {
        struct hvutil_transport *hvt;
+       int mode_old;
 
        hvt = container_of(file->f_op, struct hvutil_transport, fops);
 
-       hvt->mode = HVUTIL_TRANSPORT_INIT;
+       mutex_lock(&hvt->lock);
+       mode_old = hvt->mode;
+       if (hvt->mode != HVUTIL_TRANSPORT_DESTROY)
+               hvt->mode = HVUTIL_TRANSPORT_INIT;
        /*
         * Cleanup message buffers to avoid spurious messages when the daemon
         * connects back.
         */
        hvt_reset(hvt);
+       mutex_unlock(&hvt->lock);
+
+       if (mode_old == HVUTIL_TRANSPORT_DESTROY)
+               hvt_transport_free(hvt);
 
        return 0;
 }
@@ -168,6 +208,7 @@ static void hvt_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
         * Switching to NETLINK mode. Switching to CHARDEV happens when someone
         * opens the device.
         */
+       mutex_lock(&hvt->lock);
        if (hvt->mode == HVUTIL_TRANSPORT_INIT)
                hvt->mode = HVUTIL_TRANSPORT_NETLINK;
 
@@ -175,6 +216,7 @@ static void hvt_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
                hvt_found->on_msg(msg->data, msg->len);
        else
                pr_warn("hvt_cn_callback: unexpected netlink message!\n");
+       mutex_unlock(&hvt->lock);
 }
 
 int hvutil_transport_send(struct hvutil_transport *hvt, void *msg, int len)
@@ -182,7 +224,8 @@ int hvutil_transport_send(struct hvutil_transport *hvt, void *msg, int len)
        struct cn_msg *cn_msg;
        int ret = 0;
 
-       if (hvt->mode == HVUTIL_TRANSPORT_INIT) {
+       if (hvt->mode == HVUTIL_TRANSPORT_INIT ||
+           hvt->mode == HVUTIL_TRANSPORT_DESTROY) {
                return -EINVAL;
        } else if (hvt->mode == HVUTIL_TRANSPORT_NETLINK) {
                cn_msg = kzalloc(sizeof(*cn_msg) + len, GFP_ATOMIC);
@@ -197,7 +240,12 @@ int hvutil_transport_send(struct hvutil_transport *hvt, void *msg, int len)
                return ret;
        }
        /* HVUTIL_TRANSPORT_CHARDEV */
-       mutex_lock(&hvt->outmsg_lock);
+       mutex_lock(&hvt->lock);
+       if (hvt->mode != HVUTIL_TRANSPORT_CHARDEV) {
+               ret = -EINVAL;
+               goto out_unlock;
+       }
+
        if (hvt->outmsg) {
                /* Previous message wasn't received */
                ret = -EFAULT;
@@ -211,7 +259,7 @@ int hvutil_transport_send(struct hvutil_transport *hvt, void *msg, int len)
        } else
                ret = -ENOMEM;
 out_unlock:
-       mutex_unlock(&hvt->outmsg_lock);
+       mutex_unlock(&hvt->lock);
        return ret;
 }
 
@@ -242,7 +290,7 @@ struct hvutil_transport *hvutil_transport_init(const char *name,
        hvt->mdev.fops = &hvt->fops;
 
        init_waitqueue_head(&hvt->outmsg_q);
-       mutex_init(&hvt->outmsg_lock);
+       mutex_init(&hvt->lock);
 
        spin_lock(&hvt_list_lock);
        list_add(&hvt->list, &hvt_list);
@@ -268,12 +316,25 @@ err_free_hvt:
 
 void hvutil_transport_destroy(struct hvutil_transport *hvt)
 {
+       int mode_old;
+
+       mutex_lock(&hvt->lock);
+       mode_old = hvt->mode;
+       hvt->mode = HVUTIL_TRANSPORT_DESTROY;
+       wake_up_interruptible(&hvt->outmsg_q);
+       mutex_unlock(&hvt->lock);
+
+       /*
+        * In case we were in 'chardev' mode we still have an open fd so we
+        * have to defer freeing the device. Netlink interface can be freed
+        * now.
+        */
        spin_lock(&hvt_list_lock);
        list_del(&hvt->list);
        spin_unlock(&hvt_list_lock);
        if (hvt->cn_id.idx > 0 && hvt->cn_id.val > 0)
                cn_del_callback(&hvt->cn_id);
-       misc_deregister(&hvt->mdev);
-       kfree(hvt->outmsg);
-       kfree(hvt);
+
+       if (mode_old != HVUTIL_TRANSPORT_CHARDEV)
+               hvt_transport_free(hvt);
 }