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Date: Fri, 27 Mar 2015 09:10:09 -0700
From: "K. Y. Srinivasan" <kys@...rosoft.com>
To: gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
devel@...uxdriverproject.org, olaf@...fle.de, apw@...onical.com,
vkuznets@...hat.com, jasowang@...hat.com
Cc: Dexuan Cui <decui@...rosoft.com>,
"K. Y. Srinivasan" <kys@...rosoft.com>
Subject: [PATCH 2/7] hv: don't schedule new works in vmbus_onoffer()/vmbus_onoffer_rescind()
From: Dexuan Cui <decui@...rosoft.com>
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@...rosoft.com>
Cc: K. Y. Srinivasan <kys@...rosoft.com>
Signed-off-by: K. Y. Srinivasan <kys@...rosoft.com>
---
drivers/hv/channel_mgmt.c | 157 ++++++++-------------------------------------
drivers/hv/connection.c | 6 +--
drivers/hv/hyperv_vmbus.h | 2 +-
3 files changed, 30 insertions(+), 135 deletions(-)
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 287f07b..d69864d 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -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 @@ 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);
}
/*
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 8bcd307..583d7d4 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -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;
}
}
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index f40a5a9..887287a 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -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);
--
1.7.4.1
--
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