Drivers: hv: fcopy: switch to using the hvutil_device_state state machine
Switch to using the hvutil_device_state state machine from using 3 different state variables: fcopy_transaction.active, opened, and in_hand_shake. State transitions are: -> HVUTIL_DEVICE_INIT when driver loads or on device release -> HVUTIL_READY if the handshake was successful -> HVUTIL_HOSTMSG_RECEIVED when there is a non-negotiation message from the host -> HVUTIL_USERSPACE_REQ after userspace daemon read the message -> HVUTIL_USERSPACE_RECV after/if userspace has replied -> HVUTIL_READY after we respond to the host -> HVUTIL_DEVICE_DYING on driver unload In hv_fcopy_onchannelcallback() process ICMSGTYPE_NEGOTIATE messages even when the userspace daemon is disconnected, otherwise we can make the host think we don't support FCOPY and disable the service completely. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Tested-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Vitaly Kuznetsov
Greg Kroah-Hartman
Родитель
086a6f68d6
Коммит
4c93ccccf4
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@ -47,15 +47,10 @@
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* ensure this by serializing packet processing in this driver - we do not
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* read additional packets from the VMBUs until the current packet is fully
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* handled.
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*
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* The transaction "active" state is set when we receive a request from the
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* host and we cleanup this state when the transaction is completed - when we
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* respond to the host with our response. When the transaction active state is
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* set, we defer handling incoming packets.
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*/
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static struct {
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bool active; /* transaction status - active or not */
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int state; /* hvutil_device_state */
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int recv_len; /* number of bytes received. */
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struct hv_fcopy_hdr *fcopy_msg; /* current message */
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struct hv_start_fcopy message; /* sent to daemon */
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@ -65,14 +60,6 @@ static struct {
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struct semaphore read_sema;
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} fcopy_transaction;
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static bool opened; /* currently device opened */
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/*
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* Before we can accept copy messages from the host, we need
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* to handshake with the user level daemon. This state tracks
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* if we are in the handshake phase.
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*/
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static bool in_hand_shake = true;
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static void fcopy_send_data(void);
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static void fcopy_respond_to_host(int error);
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static void fcopy_timeout_func(struct work_struct *dummy);
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@ -87,6 +74,10 @@ static void fcopy_timeout_func(struct work_struct *dummy)
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*/
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fcopy_respond_to_host(HV_E_FAIL);
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/* Transaction is finished, reset the state. */
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if (fcopy_transaction.state > HVUTIL_READY)
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fcopy_transaction.state = HVUTIL_READY;
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/* In the case the user-space daemon crashes, hangs or is killed, we
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* need to down the semaphore, otherwise, after the daemon starts next
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* time, the obsolete data in fcopy_transaction.message or
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@ -118,10 +109,9 @@ static int fcopy_handle_handshake(u32 version)
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}
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pr_info("FCP: user-mode registering done. Daemon version: %d\n",
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version);
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fcopy_transaction.active = false;
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fcopy_transaction.state = HVUTIL_READY;
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hv_poll_channel(fcopy_transaction.fcopy_context,
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hv_fcopy_onchannelcallback);
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in_hand_shake = false;
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return 0;
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}
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@ -191,8 +181,6 @@ fcopy_respond_to_host(int error)
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channel = fcopy_transaction.recv_channel;
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req_id = fcopy_transaction.recv_req_id;
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fcopy_transaction.active = false;
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icmsghdr = (struct icmsg_hdr *)
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&recv_buffer[sizeof(struct vmbuspipe_hdr)];
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@ -220,7 +208,7 @@ void hv_fcopy_onchannelcallback(void *context)
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int util_fw_version;
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int fcopy_srv_version;
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if (fcopy_transaction.active) {
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if (fcopy_transaction.state > HVUTIL_READY) {
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/*
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* We will defer processing this callback once
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* the current transaction is complete.
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@ -252,12 +240,18 @@ void hv_fcopy_onchannelcallback(void *context)
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* transaction; note transactions are serialized.
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*/
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fcopy_transaction.active = true;
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fcopy_transaction.recv_len = recvlen;
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fcopy_transaction.recv_channel = channel;
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fcopy_transaction.recv_req_id = requestid;
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fcopy_transaction.fcopy_msg = fcopy_msg;
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if (fcopy_transaction.state < HVUTIL_READY) {
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/* Userspace is not registered yet */
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fcopy_respond_to_host(HV_E_FAIL);
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return;
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}
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fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
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/*
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* Send the information to the user-level daemon.
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*/
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@ -290,10 +284,10 @@ static ssize_t fcopy_read(struct file *file, char __user *buf,
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/*
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* The channel may be rescinded and in this case, we will wakeup the
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* the thread blocked on the semaphore and we will use the opened
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* state to correctly handle this case.
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* the thread blocked on the semaphore and we will use the state to
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* correctly handle this case.
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*/
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if (!opened)
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if (fcopy_transaction.state != HVUTIL_HOSTMSG_RECEIVED)
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return -ENODEV;
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operation = fcopy_transaction.fcopy_msg->operation;
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@ -312,6 +306,8 @@ static ssize_t fcopy_read(struct file *file, char __user *buf,
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if (copy_to_user(buf, src, copy_size))
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return -EFAULT;
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fcopy_transaction.state = HVUTIL_USERSPACE_REQ;
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return copy_size;
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}
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@ -326,18 +322,23 @@ static ssize_t fcopy_write(struct file *file, const char __user *buf,
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if (copy_from_user(&response, buf, sizeof(int)))
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return -EFAULT;
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if (in_hand_shake) {
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if (fcopy_transaction.state == HVUTIL_DEVICE_INIT) {
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if (fcopy_handle_handshake(response))
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return -EINVAL;
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return sizeof(int);
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}
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if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ)
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return -EINVAL;
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/*
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* Complete the transaction by forwarding the result
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* to the host. But first, cancel the timeout.
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*/
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if (cancel_delayed_work_sync(&fcopy_timeout_work))
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if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
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fcopy_transaction.state = HVUTIL_USERSPACE_RECV;
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fcopy_respond_to_host(response);
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fcopy_transaction.state = HVUTIL_READY;
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hv_poll_channel(fcopy_transaction.fcopy_context,
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hv_fcopy_onchannelcallback);
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}
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@ -352,13 +353,9 @@ static int fcopy_open(struct inode *inode, struct file *f)
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* really an extension of this driver. We can have only
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* active open at a time.
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*/
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if (opened)
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if (fcopy_transaction.state != HVUTIL_DEVICE_INIT)
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return -EBUSY;
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/*
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* The daemon is alive; setup the state.
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*/
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opened = true;
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return 0;
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}
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@ -375,8 +372,7 @@ static int fcopy_release(struct inode *inode, struct file *f)
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/*
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* The daemon has exited; reset the state.
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*/
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in_hand_shake = true;
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opened = false;
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fcopy_transaction.state = HVUTIL_DEVICE_INIT;
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if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
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/* We haven't up()-ed the semaphore(very rare)? */
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@ -409,13 +405,6 @@ static int fcopy_dev_init(void)
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static void fcopy_dev_deinit(void)
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{
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/*
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* The device is going away - perhaps because the
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* host has rescinded the channel. Setup state so that
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* user level daemon can gracefully exit if it is blocked
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* on the read semaphore.
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*/
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opened = false;
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/*
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* Signal the semaphore as the device is
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* going away.
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@ -434,7 +423,7 @@ int hv_fcopy_init(struct hv_util_service *srv)
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* Defer processing channel callbacks until the daemon
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* has registered.
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*/
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fcopy_transaction.active = true;
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fcopy_transaction.state = HVUTIL_DEVICE_INIT;
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sema_init(&fcopy_transaction.read_sema, 0);
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return fcopy_dev_init();
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@ -442,6 +431,7 @@ int hv_fcopy_init(struct hv_util_service *srv)
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void hv_fcopy_deinit(void)
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{
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fcopy_transaction.state = HVUTIL_DEVICE_DYING;
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cancel_delayed_work_sync(&fcopy_timeout_work);
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fcopy_dev_deinit();
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}
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