]> git.ipfire.org Git - thirdparty/kernel/linux.git/commitdiff
hv: don't schedule new works in vmbus_onoffer()/vmbus_onoffer_rescind()
authorDexuan Cui <decui@microsoft.com>
Fri, 27 Mar 2015 16:10:09 +0000 (09:10 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 3 Apr 2015 14:18:02 +0000 (16:18 +0200)
Since the 2 fucntions can safely run in vmbus_connection.work_queue without
hang, we don't need to schedule new work items into the per-channel workqueue.

Actally we can even remove the per-channel workqueue now -- we'll do it
in the next patch.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/hv/channel_mgmt.c
drivers/hv/connection.c
drivers/hv/hyperv_vmbus.h

index 287f07b1bef65828438429cbeaf8a3eafa07161d..d69864d4a4d7f01bee48a1b67f3033dbafd52425 100644 (file)
@@ -23,7 +23,6 @@
 #include <linux/kernel.h>
 #include <linux/sched.h>
 #include <linux/wait.h>
-#include <linux/delay.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/list.h>
 
 #include "hyperv_vmbus.h"
 
-struct vmbus_rescind_work {
-       struct work_struct work;
-       struct vmbus_channel *channel;
-};
-
 /**
  * vmbus_prep_negotiate_resp() - Create default response for Hyper-V Negotiate message
  * @icmsghdrp: Pointer to msg header structure
@@ -134,20 +128,6 @@ fw_error:
 
 EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
 
-static void vmbus_sc_creation_cb(struct work_struct *work)
-{
-       struct vmbus_channel *newchannel = container_of(work,
-                                                       struct vmbus_channel,
-                                                       work);
-       struct vmbus_channel *primary_channel = newchannel->primary_channel;
-
-       /*
-        * On entry sc_creation_callback has been already verified to
-        * be non-NULL.
-        */
-       primary_channel->sc_creation_callback(newchannel);
-}
-
 /*
  * alloc_channel - Allocate and initialize a vmbus channel object
  */
@@ -206,40 +186,6 @@ static void free_channel(struct vmbus_channel *channel)
        queue_work(vmbus_connection.work_queue, &channel->work);
 }
 
-static void process_rescind_fn(struct work_struct *work)
-{
-       struct vmbus_rescind_work *rc_work;
-       struct vmbus_channel *channel;
-       struct device *dev;
-
-       rc_work = container_of(work, struct vmbus_rescind_work, work);
-       channel = rc_work->channel;
-
-       /*
-        * We have already acquired a reference on the channel
-        * and so it cannot vanish underneath us.
-        * It is possible (while very unlikely) that we may
-        * get here while the processing of the initial offer
-        * is still not complete. Deal with this situation by
-        * just waiting until the channel is in the correct state.
-        */
-
-       while (channel->work.func != release_channel)
-               msleep(1000);
-
-       if (channel->device_obj) {
-               dev = get_device(&channel->device_obj->device);
-               if (dev) {
-                       vmbus_device_unregister(channel->device_obj);
-                       put_device(dev);
-               }
-       } else {
-               hv_process_channel_removal(channel,
-                                          channel->offermsg.child_relid);
-       }
-       kfree(work);
-}
-
 static void percpu_channel_enq(void *arg)
 {
        struct vmbus_channel *channel = arg;
@@ -302,46 +248,6 @@ void vmbus_free_channels(void)
        }
 }
 
-static void vmbus_do_device_register(struct work_struct *work)
-{
-       struct hv_device *device_obj;
-       int ret;
-       unsigned long flags;
-       struct vmbus_channel *newchannel = container_of(work,
-                                                    struct vmbus_channel,
-                                                    work);
-
-       ret = vmbus_device_register(newchannel->device_obj);
-       if (ret != 0) {
-               pr_err("unable to add child device object (relid %d)\n",
-                       newchannel->offermsg.child_relid);
-               spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
-               list_del(&newchannel->listentry);
-               device_obj = newchannel->device_obj;
-               newchannel->device_obj = NULL;
-               spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
-
-               if (newchannel->target_cpu != get_cpu()) {
-                       put_cpu();
-                       smp_call_function_single(newchannel->target_cpu,
-                                        percpu_channel_deq, newchannel, true);
-               } else {
-                       percpu_channel_deq(newchannel);
-                       put_cpu();
-               }
-
-               kfree(device_obj);
-               if (!newchannel->rescind) {
-                       free_channel(newchannel);
-                       return;
-               }
-       }
-       /*
-        * The next state for this channel is to be freed.
-        */
-       INIT_WORK(&newchannel->work, release_channel);
-}
-
 /*
  * vmbus_process_offer - Process the offer by creating a channel/device
  * associated with this offer
@@ -410,19 +316,8 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel)
 
                        newchannel->state = CHANNEL_OPEN_STATE;
                        channel->num_sc++;
-                       if (channel->sc_creation_callback != NULL) {
-                               /*
-                                * We need to invoke the sub-channel creation
-                                * callback; invoke this in a seperate work
-                                * context since we are currently running on
-                                * the global work context in which we handle
-                                * messages from the host.
-                                */
-                               INIT_WORK(&newchannel->work,
-                                         vmbus_sc_creation_cb);
-                               queue_work(newchannel->controlwq,
-                                          &newchannel->work);
-                       }
+                       if (channel->sc_creation_callback != NULL)
+                               channel->sc_creation_callback(newchannel);
 
                        return;
                }
@@ -453,13 +348,13 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel)
         * Add the new device to the bus. This will kick off device-driver
         * binding which eventually invokes the device driver's AddDevice()
         * method.
-        * Invoke this call on the per-channel work context.
-        * Until we return from this function, rescind offer message
-        * cannot be processed as we are running on the global message
-        * handling work.
         */
-       INIT_WORK(&newchannel->work, vmbus_do_device_register);
-       queue_work(newchannel->controlwq, &newchannel->work);
+       if (vmbus_device_register(newchannel->device_obj) != 0) {
+               pr_err("unable to add child device object (relid %d)\n",
+                       newchannel->offermsg.child_relid);
+               kfree(newchannel->device_obj);
+               goto err_deq_chan;
+       }
        return;
 
 err_deq_chan:
@@ -613,31 +508,35 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 {
        struct vmbus_channel_rescind_offer *rescind;
        struct vmbus_channel *channel;
-       struct vmbus_rescind_work *rc_work;
+       unsigned long flags;
+       struct device *dev;
 
        rescind = (struct vmbus_channel_rescind_offer *)hdr;
-       channel = relid2channel(rescind->child_relid, true);
+       channel = relid2channel(rescind->child_relid);
 
        if (channel == NULL) {
                hv_process_channel_removal(NULL, rescind->child_relid);
                return;
        }
 
-       /*
-        * We have acquired a reference on the channel and have posted
-        * the rescind state. Perform further cleanup in a work context
-        * that is different from the global work context in which
-        * we process messages from the host (we are currently executing
-        * on that global context.
-        */
-       rc_work = kzalloc(sizeof(struct vmbus_rescind_work), GFP_KERNEL);
-       if (!rc_work) {
-               pr_err("Unable to allocate memory for rescind processing ");
-               return;
+       spin_lock_irqsave(&channel->lock, flags);
+       channel->rescind = true;
+       spin_unlock_irqrestore(&channel->lock, flags);
+
+       if (channel->device_obj) {
+               /*
+                * We will have to unregister this device from the
+                * driver core.
+                */
+               dev = get_device(&channel->device_obj->device);
+               if (dev) {
+                       vmbus_device_unregister(channel->device_obj);
+                       put_device(dev);
+               }
+       } else {
+               hv_process_channel_removal(channel,
+                       channel->offermsg.child_relid);
        }
-       rc_work->channel = channel;
-       INIT_WORK(&rc_work->work, process_rescind_fn);
-       schedule_work(&rc_work->work);
 }
 
 /*
index 8bcd3071c84ffa7de1bc6a1fba4c93a03c5c11fd..583d7d42b46d84916615f3e7de2c17e28a0ce813 100644 (file)
@@ -270,7 +270,7 @@ static struct vmbus_channel *pcpu_relid2channel(u32 relid)
  * relid2channel - Get the channel object given its
  * child relative id (ie channel id)
  */
-struct vmbus_channel *relid2channel(u32 relid, bool rescind)
+struct vmbus_channel *relid2channel(u32 relid)
 {
        struct vmbus_channel *channel;
        struct vmbus_channel *found_channel  = NULL;
@@ -282,8 +282,6 @@ struct vmbus_channel *relid2channel(u32 relid, bool rescind)
        list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
                if (channel->offermsg.child_relid == relid) {
                        found_channel = channel;
-                       if (rescind)
-                               found_channel->rescind = true;
                        break;
                } else if (!list_empty(&channel->sc_list)) {
                        /*
@@ -294,8 +292,6 @@ struct vmbus_channel *relid2channel(u32 relid, bool rescind)
                                                        sc_list);
                                if (cur_sc->offermsg.child_relid == relid) {
                                        found_channel = cur_sc;
-                                       if (rescind)
-                                               found_channel->rescind = true;
                                        break;
                                }
                        }
index f40a5a935ab69faa2536628e45a68de40e20cdc3..887287ad411f767dd3b7329e8494cd3a8a6d37aa 100644 (file)
@@ -715,7 +715,7 @@ void vmbus_device_unregister(struct hv_device *device_obj);
 /* VmbusChildDeviceDestroy( */
 /* struct hv_device *); */
 
-struct vmbus_channel *relid2channel(u32 relid, bool rescind);
+struct vmbus_channel *relid2channel(u32 relid);
 
 void vmbus_free_channels(void);