diff options
Diffstat (limited to 'drivers/hv/hv_fcopy.c')
| -rw-r--r-- | drivers/hv/hv_fcopy.c | 287 |
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); } |