* [PATCH] RDMA/cma: Split apart the multiple uses of the same list heads
@ 2021-09-15 16:25 Jason Gunthorpe
2021-09-16 5:11 ` Mark Zhang
2021-10-04 19:43 ` Jason Gunthorpe
0 siblings, 2 replies; 5+ messages in thread
From: Jason Gunthorpe @ 2021-09-15 16:25 UTC (permalink / raw)
To: linux-rdma
Two list heads in the rdma_id_private are being used for multiple
purposes, to save a few bytes of memory. Give the different purposes
different names and union the memory that is clearly exclusive.
list splits into device_item and listen_any_item. device_item is threaded
onto the cma_device's list and listen_any goes onto the
listen_any_list. IDs doing any listen cannot have devices.
listen_list splits into listen_item and listen_list. listen_list is on the
parent listen any rdma_id_private and listen_item is on child listen that
is bound to a specific cma_dev.
Which name should be used in which case depends on the state and other
factors of the rdma_id_private. Remap all the confusing references to make
sense with the new names, so at least there is some hope of matching the
necessary preconditions with each access.
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
drivers/infiniband/core/cma.c | 34 ++++++++++++++++--------------
drivers/infiniband/core/cma_priv.h | 11 ++++++++--
2 files changed, 27 insertions(+), 18 deletions(-)
diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 5aa58897965df4..f671771a474288 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -453,7 +453,7 @@ static void _cma_attach_to_dev(struct rdma_id_private *id_priv,
id_priv->id.device = cma_dev->device;
id_priv->id.route.addr.dev_addr.transport =
rdma_node_get_transport(cma_dev->device->node_type);
- list_add_tail(&id_priv->list, &cma_dev->id_list);
+ list_add_tail(&id_priv->device_item, &cma_dev->id_list);
trace_cm_id_attach(id_priv, cma_dev->device);
}
@@ -470,7 +470,7 @@ static void cma_attach_to_dev(struct rdma_id_private *id_priv,
static void cma_release_dev(struct rdma_id_private *id_priv)
{
mutex_lock(&lock);
- list_del(&id_priv->list);
+ list_del_init(&id_priv->device_item);
cma_dev_put(id_priv->cma_dev);
id_priv->cma_dev = NULL;
id_priv->id.device = NULL;
@@ -854,6 +854,7 @@ __rdma_create_id(struct net *net, rdma_cm_event_handler event_handler,
init_completion(&id_priv->comp);
refcount_set(&id_priv->refcount, 1);
mutex_init(&id_priv->handler_mutex);
+ INIT_LIST_HEAD(&id_priv->device_item);
INIT_LIST_HEAD(&id_priv->listen_list);
INIT_LIST_HEAD(&id_priv->mc_list);
get_random_bytes(&id_priv->seq_num, sizeof id_priv->seq_num);
@@ -1647,7 +1648,7 @@ static struct rdma_id_private *cma_find_listener(
return id_priv;
list_for_each_entry(id_priv_dev,
&id_priv->listen_list,
- listen_list) {
+ listen_item) {
if (id_priv_dev->id.device == cm_id->device &&
cma_match_net_dev(&id_priv_dev->id,
net_dev, req))
@@ -1756,14 +1757,15 @@ static void _cma_cancel_listens(struct rdma_id_private *id_priv)
* Remove from listen_any_list to prevent added devices from spawning
* additional listen requests.
*/
- list_del(&id_priv->list);
+ list_del_init(&id_priv->listen_any_item);
while (!list_empty(&id_priv->listen_list)) {
- dev_id_priv = list_entry(id_priv->listen_list.next,
- struct rdma_id_private, listen_list);
+ dev_id_priv =
+ list_first_entry(&id_priv->listen_list,
+ struct rdma_id_private, listen_item);
/* sync with device removal to avoid duplicate destruction */
- list_del_init(&dev_id_priv->list);
- list_del(&dev_id_priv->listen_list);
+ list_del_init(&dev_id_priv->device_item);
+ list_del_init(&dev_id_priv->listen_item);
mutex_unlock(&lock);
rdma_destroy_id(&dev_id_priv->id);
@@ -2556,7 +2558,7 @@ static int cma_listen_on_dev(struct rdma_id_private *id_priv,
ret = rdma_listen(&dev_id_priv->id, id_priv->backlog);
if (ret)
goto err_listen;
- list_add_tail(&dev_id_priv->listen_list, &id_priv->listen_list);
+ list_add_tail(&dev_id_priv->listen_item, &id_priv->listen_list);
return 0;
err_listen:
/* Caller must destroy this after releasing lock */
@@ -2572,13 +2574,13 @@ static int cma_listen_on_all(struct rdma_id_private *id_priv)
int ret;
mutex_lock(&lock);
- list_add_tail(&id_priv->list, &listen_any_list);
+ list_add_tail(&id_priv->listen_any_item, &listen_any_list);
list_for_each_entry(cma_dev, &dev_list, list) {
ret = cma_listen_on_dev(id_priv, cma_dev, &to_destroy);
if (ret) {
/* Prevent racing with cma_process_remove() */
if (to_destroy)
- list_del_init(&to_destroy->list);
+ list_del_init(&to_destroy->device_item);
goto err_listen;
}
}
@@ -4868,7 +4870,7 @@ static int cma_netdev_callback(struct notifier_block *self, unsigned long event,
mutex_lock(&lock);
list_for_each_entry(cma_dev, &dev_list, list)
- list_for_each_entry(id_priv, &cma_dev->id_list, list) {
+ list_for_each_entry(id_priv, &cma_dev->id_list, device_item) {
ret = cma_netdev_change(ndev, id_priv);
if (ret)
goto out;
@@ -4928,10 +4930,10 @@ static void cma_process_remove(struct cma_device *cma_dev)
mutex_lock(&lock);
while (!list_empty(&cma_dev->id_list)) {
struct rdma_id_private *id_priv = list_first_entry(
- &cma_dev->id_list, struct rdma_id_private, list);
+ &cma_dev->id_list, struct rdma_id_private, device_item);
- list_del(&id_priv->listen_list);
- list_del_init(&id_priv->list);
+ list_del_init(&id_priv->listen_item);
+ list_del_init(&id_priv->device_item);
cma_id_get(id_priv);
mutex_unlock(&lock);
@@ -5008,7 +5010,7 @@ static int cma_add_one(struct ib_device *device)
mutex_lock(&lock);
list_add_tail(&cma_dev->list, &dev_list);
- list_for_each_entry(id_priv, &listen_any_list, list) {
+ list_for_each_entry(id_priv, &listen_any_list, listen_any_item) {
ret = cma_listen_on_dev(id_priv, cma_dev, &to_destroy);
if (ret)
goto free_listen;
diff --git a/drivers/infiniband/core/cma_priv.h b/drivers/infiniband/core/cma_priv.h
index 5c463da9984536..666d8abdfe4e84 100644
--- a/drivers/infiniband/core/cma_priv.h
+++ b/drivers/infiniband/core/cma_priv.h
@@ -55,8 +55,15 @@ struct rdma_id_private {
struct rdma_bind_list *bind_list;
struct hlist_node node;
- struct list_head list; /* listen_any_list or cma_device.list */
- struct list_head listen_list; /* per device listens */
+ union {
+ struct list_head device_item; /* On cma_device->id_list */
+ struct list_head listen_any_item; /* On listen_any_list */
+ };
+ union {
+ /* On rdma_id_private->listen_list */
+ struct list_head listen_item;
+ struct list_head listen_list;
+ };
struct cma_device *cma_dev;
struct list_head mc_list;
base-commit: ca465e1f1f9b38fe916a36f7d80c5d25f2337c81
--
2.33.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] RDMA/cma: Split apart the multiple uses of the same list heads
2021-09-15 16:25 [PATCH] RDMA/cma: Split apart the multiple uses of the same list heads Jason Gunthorpe
@ 2021-09-16 5:11 ` Mark Zhang
2021-09-16 14:17 ` Jason Gunthorpe
2021-10-04 19:39 ` Jason Gunthorpe
2021-10-04 19:43 ` Jason Gunthorpe
1 sibling, 2 replies; 5+ messages in thread
From: Mark Zhang @ 2021-09-16 5:11 UTC (permalink / raw)
To: Jason Gunthorpe, linux-rdma
On 9/16/2021 12:25 AM, Jason Gunthorpe wrote:
> External email: Use caution opening links or attachments
>
>
> Two list heads in the rdma_id_private are being used for multiple
> purposes, to save a few bytes of memory. Give the different purposes
> different names and union the memory that is clearly exclusive.
>
> list splits into device_item and listen_any_item. device_item is threaded
> onto the cma_device's list and listen_any goes onto the
> listen_any_list. IDs doing any listen cannot have devices.
>
> listen_list splits into listen_item and listen_list. listen_list is on the
> parent listen any rdma_id_private and listen_item is on child listen that
> is bound to a specific cma_dev.
>
> Which name should be used in which case depends on the state and other
> factors of the rdma_id_private. Remap all the confusing references to make
> sense with the new names, so at least there is some hope of matching the
> necessary preconditions with each access.
>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
> drivers/infiniband/core/cma.c | 34 ++++++++++++++++--------------
> drivers/infiniband/core/cma_priv.h | 11 ++++++++--
> 2 files changed, 27 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
> index 5aa58897965df4..f671771a474288 100644
> --- a/drivers/infiniband/core/cma.c
> +++ b/drivers/infiniband/core/cma.c
> @@ -453,7 +453,7 @@ static void _cma_attach_to_dev(struct rdma_id_private *id_priv,
> id_priv->id.device = cma_dev->device;
> id_priv->id.route.addr.dev_addr.transport =
> rdma_node_get_transport(cma_dev->device->node_type);
> - list_add_tail(&id_priv->list, &cma_dev->id_list);
> + list_add_tail(&id_priv->device_item, &cma_dev->id_list);
>
> trace_cm_id_attach(id_priv, cma_dev->device);
> }
> @@ -470,7 +470,7 @@ static void cma_attach_to_dev(struct rdma_id_private *id_priv,
> static void cma_release_dev(struct rdma_id_private *id_priv)
> {
> mutex_lock(&lock);
> - list_del(&id_priv->list);
> + list_del_init(&id_priv->device_item);
> cma_dev_put(id_priv->cma_dev);
> id_priv->cma_dev = NULL;
> id_priv->id.device = NULL;
> @@ -854,6 +854,7 @@ __rdma_create_id(struct net *net, rdma_cm_event_handler event_handler,
> init_completion(&id_priv->comp);
> refcount_set(&id_priv->refcount, 1);
> mutex_init(&id_priv->handler_mutex);
> + INIT_LIST_HEAD(&id_priv->device_item);
> INIT_LIST_HEAD(&id_priv->listen_list);
> INIT_LIST_HEAD(&id_priv->mc_list);
> get_random_bytes(&id_priv->seq_num, sizeof id_priv->seq_num);
> @@ -1647,7 +1648,7 @@ static struct rdma_id_private *cma_find_listener(
> return id_priv;
> list_for_each_entry(id_priv_dev,
> &id_priv->listen_list,
> - listen_list) {
> + listen_item) {
> if (id_priv_dev->id.device == cm_id->device &&
> cma_match_net_dev(&id_priv_dev->id,
> net_dev, req))
> @@ -1756,14 +1757,15 @@ static void _cma_cancel_listens(struct rdma_id_private *id_priv)
> * Remove from listen_any_list to prevent added devices from spawning
> * additional listen requests.
> */
> - list_del(&id_priv->list);
> + list_del_init(&id_priv->listen_any_item);
>
> while (!list_empty(&id_priv->listen_list)) {
> - dev_id_priv = list_entry(id_priv->listen_list.next,
> - struct rdma_id_private, listen_list);
> + dev_id_priv =
> + list_first_entry(&id_priv->listen_list,
> + struct rdma_id_private, listen_item);
> /* sync with device removal to avoid duplicate destruction */
> - list_del_init(&dev_id_priv->list);
> - list_del(&dev_id_priv->listen_list);
> + list_del_init(&dev_id_priv->device_item);
> + list_del_init(&dev_id_priv->listen_item);
> mutex_unlock(&lock);
>
> rdma_destroy_id(&dev_id_priv->id);
> @@ -2556,7 +2558,7 @@ static int cma_listen_on_dev(struct rdma_id_private *id_priv,
> ret = rdma_listen(&dev_id_priv->id, id_priv->backlog);
> if (ret)
> goto err_listen;
> - list_add_tail(&dev_id_priv->listen_list, &id_priv->listen_list);
> + list_add_tail(&dev_id_priv->listen_item, &id_priv->listen_list);
> return 0;
> err_listen:
> /* Caller must destroy this after releasing lock */
> @@ -2572,13 +2574,13 @@ static int cma_listen_on_all(struct rdma_id_private *id_priv)
> int ret;
>
> mutex_lock(&lock);
> - list_add_tail(&id_priv->list, &listen_any_list);
> + list_add_tail(&id_priv->listen_any_item, &listen_any_list);
> list_for_each_entry(cma_dev, &dev_list, list) {
> ret = cma_listen_on_dev(id_priv, cma_dev, &to_destroy);
> if (ret) {
> /* Prevent racing with cma_process_remove() */
> if (to_destroy)
> - list_del_init(&to_destroy->list);
> + list_del_init(&to_destroy->device_item);
> goto err_listen;
> }
> }
> @@ -4868,7 +4870,7 @@ static int cma_netdev_callback(struct notifier_block *self, unsigned long event,
>
> mutex_lock(&lock);
> list_for_each_entry(cma_dev, &dev_list, list)
> - list_for_each_entry(id_priv, &cma_dev->id_list, list) {
> + list_for_each_entry(id_priv, &cma_dev->id_list, device_item) {
> ret = cma_netdev_change(ndev, id_priv);
> if (ret)
> goto out;
> @@ -4928,10 +4930,10 @@ static void cma_process_remove(struct cma_device *cma_dev)
> mutex_lock(&lock);
> while (!list_empty(&cma_dev->id_list)) {
> struct rdma_id_private *id_priv = list_first_entry(
> - &cma_dev->id_list, struct rdma_id_private, list);
> + &cma_dev->id_list, struct rdma_id_private, device_item);
>
> - list_del(&id_priv->listen_list);
> - list_del_init(&id_priv->list);
> + list_del_init(&id_priv->listen_item);
Should it still be
list_del(&id_priv->listen_list);
as it isn't dev_id_priv?
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] RDMA/cma: Split apart the multiple uses of the same list heads
2021-09-16 5:11 ` Mark Zhang
@ 2021-09-16 14:17 ` Jason Gunthorpe
2021-10-04 19:39 ` Jason Gunthorpe
1 sibling, 0 replies; 5+ messages in thread
From: Jason Gunthorpe @ 2021-09-16 14:17 UTC (permalink / raw)
To: Mark Zhang; +Cc: linux-rdma
On Thu, Sep 16, 2021 at 01:11:14PM +0800, Mark Zhang wrote:
> > @@ -4928,10 +4930,10 @@ static void cma_process_remove(struct cma_device *cma_dev)
> > mutex_lock(&lock);
> > while (!list_empty(&cma_dev->id_list)) {
> > struct rdma_id_private *id_priv = list_first_entry(
> > - &cma_dev->id_list, struct rdma_id_private, list);
> > + &cma_dev->id_list, struct rdma_id_private, device_item);
> >
> > - list_del(&id_priv->listen_list);
> > - list_del_init(&id_priv->list);
> > + list_del_init(&id_priv->listen_item);
>
> Should it still be
> list_del(&id_priv->listen_list);
> as it isn't dev_id_priv?
Yes, probably should stay here, but it isn't entirely sane
The next code block must trigger the list_del or the
wait_for_completion() below will block forever.
The whole RDMA_CM_EVENT_DEVICE_REMOVAL bit is kind of insane and needs
some cleaning. For instance I think it is a bug if any ULP doesn't
return 1 from the event.
Jason
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] RDMA/cma: Split apart the multiple uses of the same list heads
2021-09-16 5:11 ` Mark Zhang
2021-09-16 14:17 ` Jason Gunthorpe
@ 2021-10-04 19:39 ` Jason Gunthorpe
1 sibling, 0 replies; 5+ messages in thread
From: Jason Gunthorpe @ 2021-10-04 19:39 UTC (permalink / raw)
To: Mark Zhang; +Cc: linux-rdma
On Thu, Sep 16, 2021 at 01:11:14PM +0800, Mark Zhang wrote:
> > @@ -4928,10 +4930,10 @@ static void cma_process_remove(struct cma_device *cma_dev)
> > mutex_lock(&lock);
> > while (!list_empty(&cma_dev->id_list)) {
> > struct rdma_id_private *id_priv = list_first_entry(
> > - &cma_dev->id_list, struct rdma_id_private, list);
> > + &cma_dev->id_list, struct rdma_id_private, device_item);
> >
> > - list_del(&id_priv->listen_list);
> > - list_del_init(&id_priv->list);
> > + list_del_init(&id_priv->listen_item);
>
> Should it still be
> list_del(&id_priv->listen_list);
> as it isn't dev_id_priv?
Actually I misunderstood your question
Yes, it should be listen_item - it makes no sense to delete a
list - that would just randomly remove the first item.
At this point we are iterating over a device list and the rules have
device id_privs using the list_item side of the union. Only IDs on
the listen_any_list use the listen_list side.
Jason
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] RDMA/cma: Split apart the multiple uses of the same list heads
2021-09-15 16:25 [PATCH] RDMA/cma: Split apart the multiple uses of the same list heads Jason Gunthorpe
2021-09-16 5:11 ` Mark Zhang
@ 2021-10-04 19:43 ` Jason Gunthorpe
1 sibling, 0 replies; 5+ messages in thread
From: Jason Gunthorpe @ 2021-10-04 19:43 UTC (permalink / raw)
To: linux-rdma
On Wed, Sep 15, 2021 at 01:25:19PM -0300, Jason Gunthorpe wrote:
> Two list heads in the rdma_id_private are being used for multiple
> purposes, to save a few bytes of memory. Give the different purposes
> different names and union the memory that is clearly exclusive.
>
> list splits into device_item and listen_any_item. device_item is threaded
> onto the cma_device's list and listen_any goes onto the
> listen_any_list. IDs doing any listen cannot have devices.
>
> listen_list splits into listen_item and listen_list. listen_list is on the
> parent listen any rdma_id_private and listen_item is on child listen that
> is bound to a specific cma_dev.
>
> Which name should be used in which case depends on the state and other
> factors of the rdma_id_private. Remap all the confusing references to make
> sense with the new names, so at least there is some hope of matching the
> necessary preconditions with each access.
>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
> drivers/infiniband/core/cma.c | 34 ++++++++++++++++--------------
> drivers/infiniband/core/cma_priv.h | 11 ++++++++--
> 2 files changed, 27 insertions(+), 18 deletions(-)
Applied to for-next
Jason
^ permalink raw reply [flat|nested] 5+ messages in thread
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2021-09-15 16:25 [PATCH] RDMA/cma: Split apart the multiple uses of the same list heads Jason Gunthorpe
2021-09-16 5:11 ` Mark Zhang
2021-09-16 14:17 ` Jason Gunthorpe
2021-10-04 19:39 ` Jason Gunthorpe
2021-10-04 19:43 ` Jason Gunthorpe
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