1 files changed, 96 insertions, 191 deletions

diff --git a/drivers/hv/hv_fcopy.c b/drivers/hv/hv_fcopy.c
index cd453e4b2a07..b50dd330cf31 100644
--- a/drivers/hv/hv_fcopy.c
+++ b/drivers/hv/hv_fcopy.c
@@ -19,17 +19,13 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#include <linux/semaphore.h>
-#include <linux/fs.h>
 #include <linux/nls.h>
 #include <linux/workqueue.h>
-#include <linux/cdev.h>
 #include <linux/hyperv.h>
 #include <linux/sched.h>
-#include <linux/uaccess.h>
-#include <linux/miscdevice.h>
 
 #include "hyperv_vmbus.h"
+#include "hv_utils_transport.h"
 
 #define WIN8_SRV_MAJOR          1
 #define WIN8_SRV_MINOR          1
@@ -47,39 +43,31 @@
  * ensure this by serializing packet processing in this driver - we do not
  * read additional packets from the VMBUs until the current packet is fully
  * handled.
- *
- * The transaction "active" state is set when we receive a request from the
- * host and we cleanup this state when the transaction is completed - when we
- * respond to the host with our response. When the transaction active state is
- * set, we defer handling incoming packets.
  */
 
 static struct {
-        bool active; /* transaction status - active or not */
+        int state;   /* hvutil_device_state */
         int recv_len; /* number of bytes received. */
         struct hv_fcopy_hdr  *fcopy_msg; /* current message */
-        struct hv_start_fcopy  message; /*  sent to daemon */
         struct vmbus_channel *recv_channel; /* chn we got the request */
         u64 recv_req_id; /* request ID. */
         void *fcopy_context; /* for the channel callback */
-        struct semaphore read_sema;
 } fcopy_transaction;
 
-static bool opened; /* currently device opened */
-
-/*
- * Before we can accept copy messages from the host, we need
- * to handshake with the user level daemon. This state tracks
- * if we are in the handshake phase.
- */
-static bool in_hand_shake = true;
-static void fcopy_send_data(void);
 static void fcopy_respond_to_host(int error);
-static void fcopy_work_func(struct work_struct *dummy);
-static DECLARE_DELAYED_WORK(fcopy_work, fcopy_work_func);
+static void fcopy_send_data(struct work_struct *dummy);
+static void fcopy_timeout_func(struct work_struct *dummy);
+static DECLARE_DELAYED_WORK(fcopy_timeout_work, fcopy_timeout_func);
+static DECLARE_WORK(fcopy_send_work, fcopy_send_data);
+static const char fcopy_devname[] = "vmbus/hv_fcopy";
 static u8 *recv_buffer;
+static struct hvutil_transport *hvt;
+/*
+ * This state maintains the version number registered by the daemon.
+ */
+static int dm_reg_value;
 
-static void fcopy_work_func(struct work_struct *dummy)
+static void fcopy_timeout_func(struct work_struct *dummy)
 {
         /*
          * If the timer fires, the user-mode component has not responded;
@@ -87,23 +75,28 @@ static void fcopy_work_func(struct work_struct *dummy)
          */
         fcopy_respond_to_host(HV_E_FAIL);
 
-        /* In the case the user-space daemon crashes, hangs or is killed, we
-         * need to down the semaphore, otherwise, after the daemon starts next
-         * time, the obsolete data in fcopy_transaction.message or
-         * fcopy_transaction.fcopy_msg will be used immediately.
-         *
-         * NOTE: fcopy_read() happens to get the semaphore (very rare)? We're
-         * still OK, because we've reported the failure to the host.
-         */
-        if (down_trylock(&fcopy_transaction.read_sema))
-                ;
+        /* Transaction is finished, reset the state. */
+        if (fcopy_transaction.state > HVUTIL_READY)
+                fcopy_transaction.state = HVUTIL_READY;
 
+        hv_poll_channel(fcopy_transaction.fcopy_context,
+                        hv_fcopy_onchannelcallback);
 }
 
 static int fcopy_handle_handshake(u32 version)
 {
+        u32 our_ver = FCOPY_CURRENT_VERSION;
+
         switch (version) {
-        case FCOPY_CURRENT_VERSION:
+        case FCOPY_VERSION_0:
+                /* Daemon doesn't expect us to reply */
+                dm_reg_value = version;
+                break;
+        case FCOPY_VERSION_1:
+                /* Daemon expects us to reply with our own version */
+                if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver)))
+                        return -EFAULT;
+                dm_reg_value = version;
                 break;
         default:
                 /*
@@ -114,20 +107,20 @@ static int fcopy_handle_handshake(u32 version)
                  */
                 return -EINVAL;
         }
-        pr_info("FCP: user-mode registering done. Daemon version: %d\n",
-                version);
-        fcopy_transaction.active = false;
-        if (fcopy_transaction.fcopy_context)
-                hv_fcopy_onchannelcallback(fcopy_transaction.fcopy_context);
-        in_hand_shake = false;
+        pr_debug("FCP: userspace daemon ver. %d registered\n", version);
+        fcopy_transaction.state = HVUTIL_READY;
+        hv_poll_channel(fcopy_transaction.fcopy_context,
+                        hv_fcopy_onchannelcallback);
         return 0;
 }
 
-static void fcopy_send_data(void)
+static void fcopy_send_data(struct work_struct *dummy)
 {
-        struct hv_start_fcopy *smsg_out = &fcopy_transaction.message;
+        struct hv_start_fcopy smsg_out;
         int operation = fcopy_transaction.fcopy_msg->operation;
         struct hv_start_fcopy *smsg_in;
+        void *out_src;
+        int rc, out_len;
 
         /*
          * The  strings sent from the host are encoded in
@@ -142,26 +135,39 @@ static void fcopy_send_data(void)
 
         switch (operation) {
         case START_FILE_COPY:
-                memset(smsg_out, 0, sizeof(struct hv_start_fcopy));
-                smsg_out->hdr.operation = operation;
+                out_len = sizeof(struct hv_start_fcopy);
+                memset(&smsg_out, 0, out_len);
+                smsg_out.hdr.operation = operation;
                 smsg_in = (struct hv_start_fcopy *)fcopy_transaction.fcopy_msg;
 
                 utf16s_to_utf8s((wchar_t *)smsg_in->file_name, W_MAX_PATH,
                                 UTF16_LITTLE_ENDIAN,
-                                (__u8 *)smsg_out->file_name, W_MAX_PATH - 1);
+                                (__u8 *)&smsg_out.file_name, W_MAX_PATH - 1);
 
                 utf16s_to_utf8s((wchar_t *)smsg_in->path_name, W_MAX_PATH,
                                 UTF16_LITTLE_ENDIAN,
-                                (__u8 *)smsg_out->path_name, W_MAX_PATH - 1);
+                                (__u8 *)&smsg_out.path_name, W_MAX_PATH - 1);
 
-                smsg_out->copy_flags = smsg_in->copy_flags;
-                smsg_out->file_size = smsg_in->file_size;
+                smsg_out.copy_flags = smsg_in->copy_flags;
+                smsg_out.file_size = smsg_in->file_size;
+                out_src = &smsg_out;
                 break;
 
         default:
+                out_src = fcopy_transaction.fcopy_msg;
+                out_len = fcopy_transaction.recv_len;
                 break;
         }
-        up(&fcopy_transaction.read_sema);
+
+        fcopy_transaction.state = HVUTIL_USERSPACE_REQ;
+        rc = hvutil_transport_send(hvt, out_src, out_len);
+        if (rc) {
+                pr_debug("FCP: failed to communicate to the daemon: %d\n", rc);
+                if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
+                        fcopy_respond_to_host(HV_E_FAIL);
+                        fcopy_transaction.state = HVUTIL_READY;
+                }
+        }
         return;
 }
 
@@ -189,8 +195,6 @@ fcopy_respond_to_host(int error)
         channel = fcopy_transaction.recv_channel;
         req_id = fcopy_transaction.recv_req_id;
 
-        fcopy_transaction.active = false;
-
         icmsghdr = (struct icmsg_hdr *)
                         &recv_buffer[sizeof(struct vmbuspipe_hdr)];
 
@@ -218,7 +222,7 @@ void hv_fcopy_onchannelcallback(void *context)
         int util_fw_version;
         int fcopy_srv_version;
 
-        if (fcopy_transaction.active) {
+        if (fcopy_transaction.state > HVUTIL_READY) {
                 /*
                  * We will defer processing this callback once
                  * the current transaction is complete.
@@ -226,6 +230,7 @@ void hv_fcopy_onchannelcallback(void *context)
                 fcopy_transaction.fcopy_context = context;
                 return;
         }
+        fcopy_transaction.fcopy_context = NULL;
 
         vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
                          &requestid);
@@ -249,17 +254,23 @@ void hv_fcopy_onchannelcallback(void *context)
                  * transaction; note transactions are serialized.
                  */
 
-                fcopy_transaction.active = true;
                 fcopy_transaction.recv_len = recvlen;
                 fcopy_transaction.recv_channel = channel;
                 fcopy_transaction.recv_req_id = requestid;
                 fcopy_transaction.fcopy_msg = fcopy_msg;
 
+                if (fcopy_transaction.state < HVUTIL_READY) {
+                        /* Userspace is not registered yet */
+                        fcopy_respond_to_host(HV_E_FAIL);
+                        return;
+                }
+                fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
+
                 /*
                  * Send the information to the user-level daemon.
                  */
-                schedule_delayed_work(&fcopy_work, 5*HZ);
-                fcopy_send_data();
+                schedule_work(&fcopy_send_work);
+                schedule_delayed_work(&fcopy_timeout_work, 5*HZ);
                 return;
         }
         icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
@@ -267,155 +278,44 @@ void hv_fcopy_onchannelcallback(void *context)
                         VM_PKT_DATA_INBAND, 0);
 }
 
-/*
- * Create a char device that can support read/write for passing
- * the payload.
- */
-
-static ssize_t fcopy_read(struct file *file, char __user *buf,
-                size_t count, loff_t *ppos)
-{
-        void *src;
-        size_t copy_size;
-        int operation;
-
-        /*
-         * Wait until there is something to be read.
-         */
-        if (down_interruptible(&fcopy_transaction.read_sema))
-                return -EINTR;
-
-        /*
-         * The channel may be rescinded and in this case, we will wakeup the
-         * the thread blocked on the semaphore and we will use the opened
-         * state to correctly handle this case.
-         */
-        if (!opened)
-                return -ENODEV;
-
-        operation = fcopy_transaction.fcopy_msg->operation;
-
-        if (operation == START_FILE_COPY) {
-                src = &fcopy_transaction.message;
-                copy_size = sizeof(struct hv_start_fcopy);
-                if (count < copy_size)
-                        return 0;
-        } else {
-                src = fcopy_transaction.fcopy_msg;
-                copy_size = sizeof(struct hv_do_fcopy);
-                if (count < copy_size)
-                        return 0;
-        }
-        if (copy_to_user(buf, src, copy_size))
-                return -EFAULT;
-
-        return copy_size;
-}
-
-static ssize_t fcopy_write(struct file *file, const char __user *buf,
-                        size_t count, loff_t *ppos)
+/* Callback when data is received from userspace */
+static int fcopy_on_msg(void *msg, int len)
 {
-        int response = 0;
+        int *val = (int *)msg;
 
-        if (count != sizeof(int))
+        if (len != sizeof(int))
                 return -EINVAL;
 
-        if (copy_from_user(&response, buf, sizeof(int)))
-                return -EFAULT;
+        if (fcopy_transaction.state == HVUTIL_DEVICE_INIT)
+                return fcopy_handle_handshake(*val);
 
-        if (in_hand_shake) {
-                if (fcopy_handle_handshake(response))
-                        return -EINVAL;
-                return sizeof(int);
-        }
+        if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ)
+                return -EINVAL;
 
         /*
          * Complete the transaction by forwarding the result
          * to the host. But first, cancel the timeout.
          */
-        if (cancel_delayed_work_sync(&fcopy_work))
-                fcopy_respond_to_host(response);
-
-        return sizeof(int);
-}
-
-static int fcopy_open(struct inode *inode, struct file *f)
-{
-        /*
-         * The user level daemon that will open this device is
-         * really an extension of this driver. We can have only
-         * active open at a time.
-         */
-        if (opened)
-                return -EBUSY;
+        if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
+                fcopy_transaction.state = HVUTIL_USERSPACE_RECV;
+                fcopy_respond_to_host(*val);
+                fcopy_transaction.state = HVUTIL_READY;
+                hv_poll_channel(fcopy_transaction.fcopy_context,
+                                hv_fcopy_onchannelcallback);
+        }
 
-        /*
-         * The daemon is alive; setup the state.
-         */
-        opened = true;
         return 0;
 }
 
-/* XXX: there are still some tricky corner cases, e.g.,
- * 1) In a SMP guest, when fcopy_release() runs between
- * schedule_delayed_work() and fcopy_send_data(), there is
- * still a chance an obsolete message will be queued.
- *
- * 2) When the fcopy daemon is running, if we unload the driver,
- * we'll notice a kernel oops when we kill the daemon later.
- */
-static int fcopy_release(struct inode *inode, struct file *f)
+static void fcopy_on_reset(void)
 {
         /*
          * The daemon has exited; reset the state.
          */
-        in_hand_shake = true;
-        opened = false;
+        fcopy_transaction.state = HVUTIL_DEVICE_INIT;
 
-        if (cancel_delayed_work_sync(&fcopy_work)) {
-                /* We haven't up()-ed the semaphore(very rare)? */
-                if (down_trylock(&fcopy_transaction.read_sema))
-                        ;
+        if (cancel_delayed_work_sync(&fcopy_timeout_work))
                 fcopy_respond_to_host(HV_E_FAIL);
-        }
-        return 0;
-}
-
-
-static const struct file_operations fcopy_fops = {
-        .read           = fcopy_read,
-        .write          = fcopy_write,
-        .release        = fcopy_release,
-        .open           = fcopy_open,
-};
-
-static struct miscdevice fcopy_misc = {
-        .minor          = MISC_DYNAMIC_MINOR,
-        .name           = "vmbus/hv_fcopy",
-        .fops           = &fcopy_fops,
-};
-
-static int fcopy_dev_init(void)
-{
-        return misc_register(&fcopy_misc);
-}
-
-static void fcopy_dev_deinit(void)
-{
-
-        /*
-         * The device is going away - perhaps because the
-         * host has rescinded the channel. Setup state so that
-         * user level daemon can gracefully exit if it is blocked
-         * on the read semaphore.
-         */
-        opened = false;
-        /*
-         * Signal the semaphore as the device is
-         * going away.
-         */
-        up(&fcopy_transaction.read_sema);
-        misc_deregister(&fcopy_misc);
 }
 
 int hv_fcopy_init(struct hv_util_service *srv)
@@ -428,14 +328,19 @@ int hv_fcopy_init(struct hv_util_service *srv)
          * Defer processing channel callbacks until the daemon
          * has registered.
          */
-        fcopy_transaction.active = true;
-        sema_init(&fcopy_transaction.read_sema, 0);
+        fcopy_transaction.state = HVUTIL_DEVICE_INIT;
+
+        hvt = hvutil_transport_init(fcopy_devname, 0, 0,
+                                    fcopy_on_msg, fcopy_on_reset);
+        if (!hvt)
+                return -EFAULT;
 
-        return fcopy_dev_init();
+        return 0;
 }
 
 void hv_fcopy_deinit(void)
 {
-        cancel_delayed_work_sync(&fcopy_work);
-        fcopy_dev_deinit();
+        fcopy_transaction.state = HVUTIL_DEVICE_DYING;
+        cancel_delayed_work_sync(&fcopy_timeout_work);
+        hvutil_transport_destroy(hvt);
 }