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path: root/drivers/hv/hv_utils_transport.c
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Diffstat (limited to 'drivers/hv/hv_utils_transport.c')
-rw-r--r--drivers/hv/hv_utils_transport.c130
1 files changed, 97 insertions, 33 deletions
diff --git a/drivers/hv/hv_utils_transport.c b/drivers/hv/hv_utils_transport.c
index 6a9d80a53..4f42c0e20 100644
--- 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;
}
@@ -77,19 +82,22 @@ static ssize_t hvt_op_write(struct file *file, const char __user *buf,
{
struct hvutil_transport *hvt;
u8 *inmsg;
+ int ret;
hvt = container_of(file->f_op, struct hvutil_transport, fops);
- inmsg = kzalloc(count, GFP_KERNEL);
- if (copy_from_user(inmsg, buf, count)) {
- kfree(inmsg);
- return -EFAULT;
- }
- if (hvt->on_msg(inmsg, count))
- return -EFAULT;
+ inmsg = memdup_user(buf, count);
+ if (IS_ERR(inmsg))
+ return PTR_ERR(inmsg);
+
+ if (hvt->mode == HVUTIL_TRANSPORT_DESTROY)
+ ret = -EBADF;
+ else
+ ret = hvt->on_msg(inmsg, count);
+
kfree(inmsg);
- return count;
+ return ret ? ret : count;
}
static unsigned int hvt_op_poll(struct file *file, poll_table *wait)
@@ -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);
@@ -197,18 +240,26 @@ 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;
goto out_unlock;
}
hvt->outmsg = kzalloc(len, GFP_KERNEL);
- memcpy(hvt->outmsg, msg, len);
- hvt->outmsg_len = len;
- wake_up_interruptible(&hvt->outmsg_q);
+ if (hvt->outmsg) {
+ memcpy(hvt->outmsg, msg, len);
+ hvt->outmsg_len = len;
+ wake_up_interruptible(&hvt->outmsg_q);
+ } else
+ ret = -ENOMEM;
out_unlock:
- mutex_unlock(&hvt->outmsg_lock);
+ mutex_unlock(&hvt->lock);
return ret;
}
@@ -239,7 +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);
@@ -265,12 +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);
}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-07-04 00:18:59 +0000