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hv: don't schedule new works in vmbus_onoffer()/vmbus_onoffer_rescind()

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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>
This commit is contained in:
Dexuan Cui 2015-03-27 09:10:09 -07:00 committed by Greg Kroah-Hartman
parent 652594c7df
commit d43e2fe7da
3 changed files with 30 additions and 135 deletions
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157
drivers/hv/channel_mgmt.c
View 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>
@ -33,11 +32,6 @@
#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 @@ bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
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);
}
/*

6
drivers/hv/connection.c
View 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;
}
}

2
drivers/hv/hyperv_vmbus.h
View 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);