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authorArnaldo Carvalho de Melo <acme@redhat.com>2019-08-12 16:25:00 -0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2019-08-12 16:25:00 -0300
commit272172bd418cc32aa466588150c8001bc229c712 (patch)
treef529a66933e79ba1f3753e8185112538e861c967 /drivers/infiniband/core/device.c
parent7f06d0aa530cc61cb5e048d4eb34921dee12058a (diff)
parentd45331b00ddb179e291766617259261c112db872 (diff)
Merge remote-tracking branch 'torvalds/master' into perf/core
To get closer to upstream and check if we need to sync more UAPI headers, pick up fixes for libbpf that prevent perf's container tests from completing successfuly, etc. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'drivers/infiniband/core/device.c')
-rw-r--r--drivers/infiniband/core/device.c102
1 files changed, 68 insertions, 34 deletions
diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index 9773145dee09..ea8661a00651 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -94,11 +94,17 @@ static DEFINE_XARRAY_FLAGS(devices, XA_FLAGS_ALLOC);
static DECLARE_RWSEM(devices_rwsem);
#define DEVICE_REGISTERED XA_MARK_1
-static LIST_HEAD(client_list);
+static u32 highest_client_id;
#define CLIENT_REGISTERED XA_MARK_1
static DEFINE_XARRAY_FLAGS(clients, XA_FLAGS_ALLOC);
static DECLARE_RWSEM(clients_rwsem);
+static void ib_client_put(struct ib_client *client)
+{
+ if (refcount_dec_and_test(&client->uses))
+ complete(&client->uses_zero);
+}
+
/*
* If client_data is registered then the corresponding client must also still
* be registered.
@@ -661,6 +667,14 @@ static int add_client_context(struct ib_device *device,
down_write(&device->client_data_rwsem);
/*
+ * So long as the client is registered hold both the client and device
+ * unregistration locks.
+ */
+ if (!refcount_inc_not_zero(&client->uses))
+ goto out_unlock;
+ refcount_inc(&device->refcount);
+
+ /*
* Another caller to add_client_context got here first and has already
* completely initialized context.
*/
@@ -683,6 +697,9 @@ static int add_client_context(struct ib_device *device,
return 0;
out:
+ ib_device_put(device);
+ ib_client_put(client);
+out_unlock:
up_write(&device->client_data_rwsem);
return ret;
}
@@ -702,7 +719,7 @@ static void remove_client_context(struct ib_device *device,
client_data = xa_load(&device->client_data, client_id);
xa_clear_mark(&device->client_data, client_id, CLIENT_DATA_REGISTERED);
client = xa_load(&clients, client_id);
- downgrade_write(&device->client_data_rwsem);
+ up_write(&device->client_data_rwsem);
/*
* Notice we cannot be holding any exclusive locks when calling the
@@ -712,17 +729,13 @@ static void remove_client_context(struct ib_device *device,
*
* For this reason clients and drivers should not call the
* unregistration functions will holdling any locks.
- *
- * It tempting to drop the client_data_rwsem too, but this is required
- * to ensure that unregister_client does not return until all clients
- * are completely unregistered, which is required to avoid module
- * unloading races.
*/
if (client->remove)
client->remove(device, client_data);
xa_erase(&device->client_data, client_id);
- up_read(&device->client_data_rwsem);
+ ib_device_put(device);
+ ib_client_put(client);
}
static int alloc_port_data(struct ib_device *device)
@@ -1224,7 +1237,7 @@ static int setup_device(struct ib_device *device)
static void disable_device(struct ib_device *device)
{
- struct ib_client *client;
+ u32 cid;
WARN_ON(!refcount_read(&device->refcount));
@@ -1232,10 +1245,19 @@ static void disable_device(struct ib_device *device)
xa_clear_mark(&devices, device->index, DEVICE_REGISTERED);
up_write(&devices_rwsem);
+ /*
+ * Remove clients in LIFO order, see assign_client_id. This could be
+ * more efficient if xarray learns to reverse iterate. Since no new
+ * clients can be added to this ib_device past this point we only need
+ * the maximum possible client_id value here.
+ */
down_read(&clients_rwsem);
- list_for_each_entry_reverse(client, &client_list, list)
- remove_client_context(device, client->client_id);
+ cid = highest_client_id;
up_read(&clients_rwsem);
+ while (cid) {
+ cid--;
+ remove_client_context(device, cid);
+ }
/* Pairs with refcount_set in enable_device */
ib_device_put(device);
@@ -1662,30 +1684,31 @@ static int assign_client_id(struct ib_client *client)
/*
* The add/remove callbacks must be called in FIFO/LIFO order. To
* achieve this we assign client_ids so they are sorted in
- * registration order, and retain a linked list we can reverse iterate
- * to get the LIFO order. The extra linked list can go away if xarray
- * learns to reverse iterate.
+ * registration order.
*/
- if (list_empty(&client_list)) {
- client->client_id = 0;
- } else {
- struct ib_client *last;
-
- last = list_last_entry(&client_list, struct ib_client, list);
- client->client_id = last->client_id + 1;
- }
+ client->client_id = highest_client_id;
ret = xa_insert(&clients, client->client_id, client, GFP_KERNEL);
if (ret)
goto out;
+ highest_client_id++;
xa_set_mark(&clients, client->client_id, CLIENT_REGISTERED);
- list_add_tail(&client->list, &client_list);
out:
up_write(&clients_rwsem);
return ret;
}
+static void remove_client_id(struct ib_client *client)
+{
+ down_write(&clients_rwsem);
+ xa_erase(&clients, client->client_id);
+ for (; highest_client_id; highest_client_id--)
+ if (xa_load(&clients, highest_client_id - 1))
+ break;
+ up_write(&clients_rwsem);
+}
+
/**
* ib_register_client - Register an IB client
* @client:Client to register
@@ -1705,6 +1728,8 @@ int ib_register_client(struct ib_client *client)
unsigned long index;
int ret;
+ refcount_set(&client->uses, 1);
+ init_completion(&client->uses_zero);
ret = assign_client_id(client);
if (ret)
return ret;
@@ -1740,21 +1765,30 @@ void ib_unregister_client(struct ib_client *client)
unsigned long index;
down_write(&clients_rwsem);
+ ib_client_put(client);
xa_clear_mark(&clients, client->client_id, CLIENT_REGISTERED);
up_write(&clients_rwsem);
- /*
- * Every device still known must be serialized to make sure we are
- * done with the client callbacks before we return.
- */
- down_read(&devices_rwsem);
- xa_for_each (&devices, index, device)
+
+ /* We do not want to have locks while calling client->remove() */
+ rcu_read_lock();
+ xa_for_each (&devices, index, device) {
+ if (!ib_device_try_get(device))
+ continue;
+ rcu_read_unlock();
+
remove_client_context(device, client->client_id);
- up_read(&devices_rwsem);
- down_write(&clients_rwsem);
- list_del(&client->list);
- xa_erase(&clients, client->client_id);
- up_write(&clients_rwsem);
+ ib_device_put(device);
+ rcu_read_lock();
+ }
+ rcu_read_unlock();
+
+ /*
+ * remove_client_context() is not a fence, it can return even though a
+ * removal is ongoing. Wait until all removals are completed.
+ */
+ wait_for_completion(&client->uses_zero);
+ remove_client_id(client);
}
EXPORT_SYMBOL(ib_unregister_client);
generated by cgit v1.2.3-70-g09d2 (git 2.48.1) at 2025-04-26 08:54:44 +0000