simplify locking in netfront accelerator
Signed-off-by <kmansley@xxxxxxxxxxxxxx>
diff -r c75337e70043 drivers/xen/netfront/accel.c
--- a/drivers/xen/netfront/accel.c Tue Oct 30 13:26:47 2007 +0000
+++ b/drivers/xen/netfront/accel.c Tue Oct 30 16:31:38 2007 +0000
@@ -31,7 +31,7 @@
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/list.h>
-#include <linux/kref.h>
+#include <linux/mutex.h>
#include <xen/xenbus.h>
@@ -45,29 +45,17 @@
#define WPRINTK(fmt, args...) \
printk(KERN_WARNING "netfront/accel: " fmt, ##args)
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 5)
-#define kref_init(x,y) kref_init(x,y)
-#define kref_put(x,y) kref_put(x)
-#else
-#define kref_init(x,y) kref_init(x)
-#define kref_put(x,y) kref_put(x,y)
-#endif
-
/*
* List of all netfront accelerator plugin modules available. Each
* list entry is of type struct netfront_accelerator.
*/
static struct list_head accelerators_list;
-/*
- * Lock to protect access to accelerators_list
- */
+/* Lock to protect access to accelerators_list */
static spinlock_t accelerators_lock;
-/* Forward declaration of kref cleanup functions */
-static void accel_kref_release(struct kref *ref);
-static void vif_kref_release(struct kref *ref);
-
+/* Mutex to prevent concurrent loads and suspends, etc. */
+DEFINE_MUTEX(accelerator_mutex);
void netif_init_accel(void)
{
@@ -105,9 +93,6 @@ void init_accelerator_vif(struct netfron
/* It's assumed that these things don't change */
np->accel_vif_state.np = np;
np->accel_vif_state.dev = dev;
-
- np->accel_vif_state.ready_for_probe = 1;
- np->accel_vif_state.need_probe = NULL;
}
@@ -130,6 +115,11 @@ static void add_accelerator_vif(struct n
static void add_accelerator_vif(struct netfront_accelerator *accelerator,
struct netfront_info *np)
{
+ unsigned flags;
+
+ /* Need lock to write list */
+ spin_lock_irqsave(&accelerator->vif_states_lock, flags);
+
if (np->accelerator == NULL) {
np->accelerator = accelerator;
@@ -142,6 +132,8 @@ static void add_accelerator_vif(struct n
*/
BUG_ON(np->accelerator != accelerator);
}
+
+ spin_unlock_irqrestore(&accelerator->vif_states_lock, flags);
}
@@ -175,9 +167,6 @@ static int init_accelerator(const char *
accelerator->hooks = hooks;
- accelerator->ready_for_probe = 1;
- accelerator->need_probe = NULL;
-
list_add(&accelerator->link, &accelerators_list);
*result = accelerator;
@@ -193,17 +182,9 @@ static void
static void
accelerator_set_vif_state_hooks(struct netfront_accel_vif_state *vif_state)
{
- /* This function must be called with the vif_state_lock held */
+ /* This function must be called with the vif_states_lock held */
DPRINTK("%p\n",vif_state);
-
- /*
- * Take references to stop hooks disappearing.
- * This persists until vif_kref gets to zero.
- */
- kref_get(&vif_state->np->accelerator->accel_kref);
- /* This persists until vif_state->hooks are cleared */
- kref_init(&vif_state->vif_kref, vif_kref_release);
/* Make sure there are no data path operations going on */
netif_poll_disable(vif_state->np->netdev);
@@ -221,47 +202,22 @@ static void accelerator_probe_new_vif(st
struct netfront_accelerator *accelerator)
{
struct netfront_accel_hooks *hooks;
- unsigned flags;
-
+
DPRINTK("\n");
- spin_lock_irqsave(&accelerator->vif_states_lock, flags);
-
- /*
- * Include this frontend device on the accelerator's list
- */
+ /* Include this frontend device on the accelerator's list */
add_accelerator_vif(accelerator, np);
hooks = accelerator->hooks;
if (hooks) {
- if (np->accel_vif_state.ready_for_probe) {
- np->accel_vif_state.ready_for_probe = 0;
-
- kref_get(&accelerator->accel_kref);
-
- spin_unlock_irqrestore(&accelerator->vif_states_lock,
- flags);
-
- hooks->new_device(np->netdev, dev);
-
- kref_put(&accelerator->accel_kref,
- accel_kref_release);
- /*
- * Hooks will get linked into vif_state by a
- * future call by the accelerator to
- * netfront_accelerator_ready()
- */
- return;
- } else {
- if (np->accel_vif_state.need_probe != NULL)
- DPRINTK("Probe request on vif awaiting
probe\n");
- np->accel_vif_state.need_probe = hooks;
- }
- }
-
- spin_unlock_irqrestore(&accelerator->vif_states_lock,
- flags);
+ hooks->new_device(np->netdev, dev);
+ /*
+ * Hooks will get linked into vif_state by a future
+ * call by the accelerator to netfront_accelerator_ready()
+ */
+ }
+
return;
}
@@ -275,10 +231,12 @@ int netfront_load_accelerator(struct net
const char *frontend)
{
struct netfront_accelerator *accelerator;
- int rc;
+ int rc = 0;
unsigned flags;
DPRINTK(" %s\n", frontend);
+
+ mutex_lock(&accelerator_mutex);
spin_lock_irqsave(&accelerators_lock, flags);
@@ -292,6 +250,7 @@ int netfront_load_accelerator(struct net
accelerator_probe_new_vif(np, dev, accelerator);
+ mutex_unlock(&accelerator_mutex);
return 0;
}
}
@@ -299,15 +258,16 @@ int netfront_load_accelerator(struct net
/* Couldn't find it, so create a new one and load the module */
if ((rc = init_accelerator(frontend, &accelerator, NULL)) < 0) {
spin_unlock_irqrestore(&accelerators_lock, flags);
+ mutex_unlock(&accelerator_mutex);
return rc;
}
spin_unlock_irqrestore(&accelerators_lock, flags);
/* Include this frontend device on the accelerator's list */
- spin_lock_irqsave(&accelerator->vif_states_lock, flags);
add_accelerator_vif(accelerator, np);
- spin_unlock_irqrestore(&accelerator->vif_states_lock, flags);
+
+ mutex_unlock(&accelerator_mutex);
DPRINTK("requesting module %s\n", frontend);
@@ -319,7 +279,7 @@ int netfront_load_accelerator(struct net
* it's up and running, and we can continue from there
*/
- return 0;
+ return rc;
}
@@ -331,21 +291,11 @@ int netfront_load_accelerator(struct net
*/
static void
accelerator_probe_vifs(struct netfront_accelerator *accelerator,
- struct netfront_accel_hooks *hooks,
- unsigned *lock_flags)
+ struct netfront_accel_hooks *hooks)
{
struct netfront_accel_vif_state *vif_state, *tmp;
- /* Calling function must have taken the vif_states_lock */
-
DPRINTK("%p\n", accelerator);
-
- /*
- * kref_init() takes a single reference to the hooks that will
- * persist until the accelerator hooks are removed (e.g. by
- * accelerator module unload)
- */
- kref_init(&accelerator->accel_kref, accel_kref_release);
/*
* Store the hooks for future calls to probe a new device, and
@@ -354,72 +304,23 @@ accelerator_probe_vifs(struct netfront_a
*/
BUG_ON(hooks == NULL);
accelerator->hooks = hooks;
-
+
+ /*
+ * currently hold accelerator_mutex, so don't need
+ * vif_states_lock to read the list
+ */
list_for_each_entry_safe(vif_state, tmp, &accelerator->vif_states,
link) {
struct netfront_info *np = vif_state->np;
-
- if (vif_state->ready_for_probe) {
- vif_state->ready_for_probe = 0;
- kref_get(&accelerator->accel_kref);
-
- /*
- * drop lock before calling hook. hooks are
- * protected by the kref
- */
- spin_unlock_irqrestore(&accelerator->vif_states_lock,
- (*lock_flags));
-
- hooks->new_device(np->netdev, vif_state->dev);
-
- kref_put(&accelerator->accel_kref, accel_kref_release);
-
- /* Retake lock for next go round the loop */
- spin_lock_irqsave(&accelerator->vif_states_lock,
- (*lock_flags));
-
- /*
- * Hooks will get linked into vif_state by a call to
- * netfront_accelerator_ready() once accelerator
- * plugin is ready for action
- */
- } else {
- if (vif_state->need_probe != NULL)
- DPRINTK("Probe request on vif awaiting
probe\n");
- vif_state->need_probe = hooks;
- }
- }
-
- /* Return with vif_states_lock held, as on entry */
-}
-
-
-/*
- * Wrapper for accelerator_probe_vifs that checks now is a good time
- * to do the probe, and postpones till previous state cleared up if
- * necessary
- */
-static void
-accelerator_probe_vifs_on_load(struct netfront_accelerator *accelerator,
- struct netfront_accel_hooks *hooks)
-{
- unsigned flags;
-
- DPRINTK("\n");
-
- spin_lock_irqsave(&accelerator->vif_states_lock, flags);
-
- if (accelerator->ready_for_probe) {
- accelerator->ready_for_probe = 0;
- accelerator_probe_vifs(accelerator, hooks, &flags);
- } else {
- if (accelerator->need_probe)
- DPRINTK("Probe request on accelerator awaiting
probe\n");
- accelerator->need_probe = hooks;
- }
-
- spin_unlock_irqrestore(&accelerator->vif_states_lock,
- flags);
+
+ hooks->new_device(np->netdev, vif_state->dev);
+
+ /*
+ * Hooks will get linked into vif_state by a call to
+ * netfront_accelerator_ready() once accelerator
+ * plugin is ready for action
+ */
+ }
}
@@ -447,6 +348,8 @@ int netfront_accelerator_loaded(int vers
}
}
+ mutex_lock(&accelerator_mutex);
+
spin_lock_irqsave(&accelerators_lock, flags);
/*
@@ -457,9 +360,9 @@ int netfront_accelerator_loaded(int vers
if (match_accelerator(frontend, accelerator)) {
spin_unlock_irqrestore(&accelerators_lock, flags);
- accelerator_probe_vifs_on_load(accelerator, hooks);
-
- return 0;
+ accelerator_probe_vifs(accelerator, hooks);
+
+ goto out;
}
}
@@ -474,6 +377,8 @@ int netfront_accelerator_loaded(int vers
spin_unlock_irqrestore(&accelerators_lock, flags);
+ out:
+ mutex_unlock(&accelerator_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(netfront_accelerator_loaded);
@@ -497,6 +402,10 @@ void netfront_accelerator_ready(const ch
list_for_each_entry(accelerator, &accelerators_list, link) {
if (match_accelerator(frontend, accelerator)) {
+ /*
+ * Mutex not held so need vif_states_lock for
+ * list
+ */
spin_lock_irqsave
(&accelerator->vif_states_lock, flags1);
@@ -509,11 +418,9 @@ void netfront_accelerator_ready(const ch
spin_unlock_irqrestore
(&accelerator->vif_states_lock, flags1);
- goto done;
+ break;
}
}
-
- done:
spin_unlock_irqrestore(&accelerators_lock, flags);
}
EXPORT_SYMBOL_GPL(netfront_accelerator_ready);
@@ -552,38 +459,24 @@ static void accelerator_remove_hooks(str
struct netfront_accel_vif_state *vif_state, *tmp;
unsigned flags;
- spin_lock_irqsave(&accelerator->vif_states_lock, flags);
-
+ /* Mutex is held so don't need vif_states_lock to iterate list */
list_for_each_entry_safe(vif_state, tmp,
&accelerator->vif_states,
link) {
+ spin_lock_irqsave(&accelerator->vif_states_lock, flags);
+
BUG_ON(vif_state->hooks == NULL);
hooks = vif_state->hooks;
accelerator_remove_single_hook(accelerator, vif_state);
- /*
- * Tell accelerator that this device is being removed,
- * and remove the reference taken when the vif_state
- * hooks were set; both must be called without lock
- * held
- */
spin_unlock_irqrestore(&accelerator->vif_states_lock, flags);
/* Last chance to get statistics from the accelerator */
hooks->get_stats(vif_state->np->netdev, &vif_state->np->stats);
hooks->remove(vif_state->dev);
-
- kref_put(&vif_state->vif_kref, vif_kref_release);
-
- spin_lock_irqsave(&accelerator->vif_states_lock, flags);
}
accelerator->hooks = NULL;
-
- spin_unlock_irqrestore(&accelerator->vif_states_lock, flags);
-
- /* Remove the reference taken when module loaded */
- kref_put(&accelerator->accel_kref, accel_kref_release);
}
@@ -597,82 +490,33 @@ void netfront_accelerator_stop(const cha
struct netfront_accelerator *accelerator;
unsigned flags;
+ mutex_lock(&accelerator_mutex);
spin_lock_irqsave(&accelerators_lock, flags);
list_for_each_entry(accelerator, &accelerators_list, link) {
if (match_accelerator(frontend, accelerator)) {
spin_unlock_irqrestore(&accelerators_lock, flags);
- /*
- * Use semaphore to ensure we know when all
- * uses of hooks are complete
- */
- sema_init(&accelerator->exit_semaphore, 0);
-
accelerator_remove_hooks(accelerator);
- /* Wait for hooks to be unused, then return */
- down(&accelerator->exit_semaphore);
-
- return;
+ goto out;
}
}
spin_unlock_irqrestore(&accelerators_lock, flags);
+ out:
+ mutex_unlock(&accelerator_mutex);
}
EXPORT_SYMBOL_GPL(netfront_accelerator_stop);
-
-
-
-int netfront_check_accelerator_queue_ready(struct net_device *dev,
- struct netfront_info *np)
-{
- struct netfront_accelerator *accelerator;
- struct netfront_accel_hooks *hooks;
- int rc = 1;
- unsigned flags;
-
- accelerator = np->accelerator;
-
- /*
- * Call the check ready accelerator hook. The use count for the
- * accelerator's hooks is incremented for the duration of the
- * call to prevent the accelerator being able to modify the
- * hooks in the middle (by, for example, unloading)
- */
- if (np->accel_vif_state.hooks && accelerator) {
- spin_lock_irqsave(&accelerator->vif_states_lock, flags);
- hooks = np->accel_vif_state.hooks;
- if (hooks && np->accelerator == accelerator) {
- kref_get(&np->accel_vif_state.vif_kref);
- spin_unlock_irqrestore
- (&accelerator->vif_states_lock, flags);
-
- rc = np->accel_vif_state.hooks->check_ready(dev);
-
- kref_put(&np->accel_vif_state.vif_kref,
- vif_kref_release);
- } else {
- spin_unlock_irqrestore
- (&accelerator->vif_states_lock, flags);
- }
- }
-
- return rc;
-}
/* Helper for call_remove and do_suspend */
static int do_remove(struct netfront_info *np, struct xenbus_device *dev,
- unsigned lock_flags, int clear_accelerator)
+ unsigned *lock_flags)
{
struct netfront_accelerator *accelerator = np->accelerator;
struct netfront_accel_hooks *hooks;
- unsigned flags;
int rc = 0;
- if(clear_accelerator)
- np->accelerator = NULL;
-
if (np->accel_vif_state.hooks) {
hooks = np->accel_vif_state.hooks;
@@ -684,27 +528,15 @@ static int do_remove(struct netfront_inf
accelerator_remove_single_hook(accelerator,
&np->accel_vif_state);
- spin_unlock_irqrestore(&accelerator->vif_states_lock,
- lock_flags);
-
- /*
- * No need to do kref_get before calling these hooks as we
- * can borrow the one we have to drop after this call
- */
-
/* Last chance to get statistics from the accelerator */
hooks->get_stats(np->netdev, &np->stats);
+ spin_unlock_irqrestore(&accelerator->vif_states_lock,
+ *lock_flags);
+
rc = hooks->remove(dev);
-
- /*
- * Remove the reference taken when the vif_state hooks
- * were set, must be called without lock held
- */
- kref_put(&np->accel_vif_state.vif_kref, vif_kref_release);
- } else {
- spin_unlock_irqrestore(&accelerator->vif_states_lock,
- lock_flags);
+
+ spin_lock_irqsave(&accelerator->vif_states_lock, *lock_flags);
}
@@ -715,16 +547,22 @@ int netfront_accelerator_call_remove(str
int netfront_accelerator_call_remove(struct netfront_info *np,
struct xenbus_device *dev)
{
+ struct netfront_accelerator *accelerator;
struct netfront_accel_vif_state *tmp_vif_state;
unsigned flags;
+ int rc = 0;
+
+ mutex_lock(&accelerator_mutex);
/* Check that we've got a device that was accelerated */
if (np->accelerator == NULL)
- return 0;
-
- spin_lock_irqsave(&np->accelerator->vif_states_lock, flags);
-
- list_for_each_entry(tmp_vif_state, &np->accelerator->vif_states,
+ goto out;
+
+ accelerator = np->accelerator;
+
+ spin_lock_irqsave(&accelerator->vif_states_lock, flags);
+
+ list_for_each_entry(tmp_vif_state, &accelerator->vif_states,
link) {
if (tmp_vif_state == &np->accel_vif_state) {
list_del(&np->accel_vif_state.link);
@@ -732,8 +570,14 @@ int netfront_accelerator_call_remove(str
}
}
- /* do_remove drops the lock for us */
- return do_remove(np, dev, flags, 1);
+ rc = do_remove(np, dev, &flags);
+
+ np->accelerator = NULL;
+
+ spin_unlock_irqrestore(&accelerator->vif_states_lock, flags);
+ out:
+ mutex_unlock(&accelerator_mutex);
+ return rc;
}
@@ -741,21 +585,26 @@ int netfront_accelerator_suspend(struct
struct xenbus_device *dev)
{
unsigned flags;
-
+ int rc = 0;
+
+ mutex_lock(&accelerator_mutex);
/* Check that we've got a device that was accelerated */
if (np->accelerator == NULL)
- return 0;
+ goto out;
/*
* Call the remove accelerator hook, but leave the vif_state
* on the accelerator's list in case there is a suspend_cancel.
*/
- spin_lock_irqsave(&np->accelerator->vif_states_lock,
- flags);
+ spin_lock_irqsave(&np->accelerator->vif_states_lock, flags);
- /* do_remove drops the lock for us */
- return do_remove(np, dev, flags, 0);
+ rc = do_remove(np, dev, &flags);
+
+ spin_unlock_irqrestore(&np->accelerator->vif_states_lock, flags);
+ out:
+ mutex_unlock(&accelerator_mutex);
+ return rc;
}
@@ -763,21 +612,18 @@ int netfront_accelerator_suspend_cancel(
struct xenbus_device *dev)
{
struct netfront_accel_vif_state *accel_vif_state = NULL;
- unsigned flags1, flags2;
-
+
+ mutex_lock(&accelerator_mutex);
+
/* Check that we've got a device that was accelerated */
if (np->accelerator == NULL)
- return 0;
-
- spin_lock_irqsave(&np->accelerator->vif_states_lock, flags);
+ goto out;
+
/* Find the vif_state from the accelerator's list */
list_for_each_entry(accel_vif_state, &np->accelerator->vif_states,
link) {
if (accel_vif_state->dev == dev) {
BUG_ON(accel_vif_state != &np->accel_vif_state);
-
-
spin_unlock_irqrestore(&np->accelerator->vif_states_lock,
- flags);
/*
* Kick things off again to restore
@@ -785,12 +631,12 @@ int netfront_accelerator_suspend_cancel(
*/
accelerator_probe_new_vif(np, dev, np->accelerator);
- return 0;
+ break;
}
}
- spin_unlock_irqrestore(&np->accelerator->vif_states_lock, flags);
-
+ out:
+ mutex_unlock(&accelerator_mutex);
return 0;
}
@@ -802,17 +648,20 @@ void netfront_accelerator_resume(struct
spinlock_t *vif_states_lock;
unsigned flags;
- /* Check that we've got a device that was accelerated */
+ mutex_lock(&accelerator_mutex);
+
+ /* Check that we've got a device that was accelerated */
if(np->accelerator == NULL)
- return;
-
- spin_lock_irqsave(&np->accelerator->vif_states_lock, flags);
-
+ goto out;
+
/* Find the vif_state from the accelerator's list */
list_for_each_entry(accel_vif_state, &np->accelerator->vif_states,
link) {
if (accel_vif_state->dev == dev) {
BUG_ON(accel_vif_state != &np->accel_vif_state);
+
+ vif_states_lock = &np->accelerator->vif_states_lock;
+ spin_lock_irqsave(vif_states_lock, flags);
/*
* Remove it from the accelerator's list so
@@ -820,15 +669,40 @@ void netfront_accelerator_resume(struct
* when they get connected
*/
list_del(&accel_vif_state->link);
- vif_states_lock = &np->accelerator->vif_states_lock;
np->accelerator = NULL;
spin_unlock_irqrestore(vif_states_lock, flags);
- return;
+ break;
}
}
- spin_unlock_irqrestore(&np->accelerator->vif_states_lock, flags);
+
+ out:
+ mutex_unlock(&accelerator_mutex);
+ return;
+}
+
+
+int netfront_check_accelerator_queue_ready(struct net_device *dev,
+ struct netfront_info *np)
+{
+ struct netfront_accelerator *accelerator;
+ struct netfront_accel_hooks *hooks;
+ int rc = 1;
+ unsigned flags;
+
+ accelerator = np->accelerator;
+
+ /* Call the check_ready accelerator hook. */
+ if (np->accel_vif_state.hooks && accelerator) {
+ spin_lock_irqsave(&accelerator->vif_states_lock, flags);
+ hooks = np->accel_vif_state.hooks;
+ if (hooks && np->accelerator == accelerator)
+ rc = np->accel_vif_state.hooks->check_ready(dev);
+ spin_unlock_irqrestore(&accelerator->vif_states_lock, flags);
+ }
+
+ return rc;
}
@@ -841,30 +715,13 @@ void netfront_accelerator_call_stop_napi
accelerator = np->accelerator;
- /*
- * Call the stop_napi_interrupts accelerator hook. The use
- * count for the accelerator's hooks is incremented for the
- * duration of the call to prevent the accelerator being able
- * to modify the hooks in the middle (by, for example,
- * unloading)
- */
-
+ /* Call the stop_napi_interrupts accelerator hook. */
if (np->accel_vif_state.hooks && accelerator != NULL) {
spin_lock_irqsave(&accelerator->vif_states_lock, flags);
hooks = np->accel_vif_state.hooks;
- if (hooks && np->accelerator == accelerator) {
- kref_get(&np->accel_vif_state.vif_kref);
- spin_unlock_irqrestore
- (&accelerator->vif_states_lock, flags);
-
+ if (hooks && np->accelerator == accelerator)
np->accel_vif_state.hooks->stop_napi_irq(dev);
-
- kref_put(&np->accel_vif_state.vif_kref,
- vif_kref_release);
- } else {
- spin_unlock_irqrestore
- (&accelerator->vif_states_lock, flags);
- }
+ spin_unlock_irqrestore(&accelerator->vif_states_lock, flags);
}
}
@@ -879,90 +736,15 @@ int netfront_accelerator_call_get_stats(
accelerator = np->accelerator;
- /*
- * Call the get_stats accelerator hook. The use count for the
- * accelerator's hooks is incremented for the duration of the
- * call to prevent the accelerator being able to modify the
- * hooks in the middle (by, for example, unloading)
- */
-
+ /* Call the get_stats accelerator hook. */
if (np->accel_vif_state.hooks && accelerator != NULL) {
- spin_lock_irqsave(accelerator->vif_states_lock, flags);
+ spin_lock_irqsave(&accelerator->vif_states_lock, flags);
hooks = np->accel_vif_state.hooks;
- if (hooks && np->accelerator == accelerator) {
- kref_get(&np->accel_vif_state.vif_kref);
- spin_unlock_irqrestore
- (&accelerator->vif_states_lock, flags);
-
+ if (hooks && np->accelerator == accelerator)
rc = np->accel_vif_state.hooks->get_stats(dev,
&np->stats);
-
- kref_put(&np->accel_vif_state.vif_kref,
- vif_kref_release);
- } else {
- spin_unlock_irqrestore
- (&accelerator->vif_states_lock, flags);
- }
+ spin_unlock_irqrestore(&accelerator->vif_states_lock, flags);
}
return rc;
}
-
-/*
- * Once all users of hooks have kref_put()'d we can signal that it's
- * safe to unload
- */
-static void accel_kref_release(struct kref *ref)
-{
- struct netfront_accelerator *accelerator =
- container_of(ref, struct netfront_accelerator, accel_kref);
- struct netfront_accel_hooks *hooks;
- unsigned flags;
-
- DPRINTK("%p\n", accelerator);
-
- /* Signal that all users of hooks are done */
- up(&accelerator->exit_semaphore);
-
- spin_lock_irqsave(&accelerator->vif_states_lock, flags);
- if (accelerator->need_probe) {
- hooks = accelerator->need_probe;
- accelerator->need_probe = NULL;
- accelerator_probe_vifs(accelerator, hooks, &flags);
- }
- else
- accelerator->ready_for_probe = 1;
-
- spin_unlock_irqrestore(&accelerator->vif_states_lock, flags);
-}
-
-
-static void vif_kref_release(struct kref *ref)
-{
- struct netfront_accel_vif_state *vif_state =
- container_of(ref, struct netfront_accel_vif_state, vif_kref);
- struct netfront_accel_hooks *hooks;
- unsigned flags;
-
- DPRINTK("%p\n", vif_state);
-
- /*
- * Now that this vif has finished using the hooks, it can
- * decrement the accelerator's global copy ref count
- */
- kref_put(&vif_state->np->accelerator->accel_kref, accel_kref_release);
-
- spin_lock_irqsave(&vif_state->np->accelerator->vif_states_lock, flags);
- if (vif_state->need_probe) {
- hooks = vif_state->need_probe;
- vif_state->need_probe = NULL;
- spin_unlock_irqrestore
- (&vif_state->np->accelerator->vif_states_lock, flags);
- hooks->new_device(vif_state->np->netdev, vif_state->dev);
- } else {
- vif_state->ready_for_probe = 1;
- spin_unlock_irqrestore
- (&vif_state->np->accelerator->vif_states_lock, flags);
- }
-}
-
diff -r c75337e70043 drivers/xen/netfront/netfront.h
--- a/drivers/xen/netfront/netfront.h Tue Oct 30 13:26:47 2007 +0000
+++ b/drivers/xen/netfront/netfront.h Tue Oct 30 16:31:18 2007 +0000
@@ -37,7 +37,6 @@
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/list.h>
-#include <linux/kref.h>
#define NET_TX_RING_SIZE __RING_SIZE((struct netif_tx_sring *)0, PAGE_SIZE)
#define NET_RX_RING_SIZE __RING_SIZE((struct netif_rx_sring *)0, PAGE_SIZE)
@@ -109,14 +108,6 @@ struct netfront_accel_vif_state {
struct xenbus_device *dev;
struct netfront_info *np;
struct netfront_accel_hooks *hooks;
-
- /*
- * Protect against removal of hooks while in use.
- */
- struct kref vif_kref;
-
- unsigned ready_for_probe;
- struct netfront_accel_hooks *need_probe;
};
/*
@@ -137,10 +128,7 @@ struct netfront_accelerator {
char *frontend;
/* The hooks into the accelerator plugin module */
struct netfront_accel_hooks *hooks;
- /*
- * Protect against removal of hooks while in use.
- */
- struct kref accel_kref;
+
/*
* List of per-netfront device state (struct
* netfront_accel_vif_state) for each netfront device that is
@@ -148,14 +136,6 @@ struct netfront_accelerator {
*/
struct list_head vif_states;
spinlock_t vif_states_lock;
- /*
- * Semaphore to signal that all users of this accelerator have
- * finished using it before module is unloaded
- */
- struct semaphore exit_semaphore;
-
- unsigned ready_for_probe;
- struct netfront_accel_hooks *need_probe;
};
struct netfront_info {
simplify_accelerator_locking
Description: Text document
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