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Subject[char-misc-next 02/18 V2] mei: revamp me clients list handling
Date
1. Use rw lock to access the me_clients list

2. Reuse already defined find functions also when
removing particular me client

3. Add wrappers for addition and deletion

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
V2: add missing mei_me_cl_put() calls to mei_host_client_init

drivers/misc/mei/client.c | 197 +++++++++++++++++++++++++++++++++------------
drivers/misc/mei/client.h | 5 +-
drivers/misc/mei/debugfs.c | 19 +++--
drivers/misc/mei/hbm.c | 3 +-
drivers/misc/mei/init.c | 1 +
drivers/misc/mei/mei_dev.h | 2 +
6 files changed, 165 insertions(+), 62 deletions(-)

diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index 9541218c10eb..7370218bb3f7 100644
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -48,14 +48,14 @@ void mei_me_cl_init(struct mei_me_client *me_cl)
*/
struct mei_me_client *mei_me_cl_get(struct mei_me_client *me_cl)
{
- if (me_cl)
- kref_get(&me_cl->refcnt);
+ if (me_cl && kref_get_unless_zero(&me_cl->refcnt))
+ return me_cl;

- return me_cl;
+ return NULL;
}

/**
- * mei_me_cl_release - unlink and free me client
+ * mei_me_cl_release - free me client
*
* Locking: called under "dev->device_lock" lock
*
@@ -65,9 +65,10 @@ static void mei_me_cl_release(struct kref *ref)
{
struct mei_me_client *me_cl =
container_of(ref, struct mei_me_client, refcnt);
- list_del(&me_cl->list);
+
kfree(me_cl);
}
+
/**
* mei_me_cl_put - decrease me client refcount and free client if necessary
*
@@ -82,51 +83,146 @@ void mei_me_cl_put(struct mei_me_client *me_cl)
}

/**
- * mei_me_cl_by_uuid - locate me client by uuid
+ * __mei_me_cl_del - delete me client form the list and decrease
+ * reference counter
+ *
+ * @dev: mei device
+ * @me_cl: me client
+ *
+ * Locking: dev->me_clients_rwsem
+ */
+static void __mei_me_cl_del(struct mei_device *dev, struct mei_me_client *me_cl)
+{
+ if (!me_cl)
+ return;
+
+ list_del(&me_cl->list);
+ mei_me_cl_put(me_cl);
+}
+
+/**
+ * mei_me_cl_add - add me client to the list
+ *
+ * @dev: mei device
+ * @me_cl: me client
+ */
+void mei_me_cl_add(struct mei_device *dev, struct mei_me_client *me_cl)
+{
+ down_write(&dev->me_clients_rwsem);
+ list_add(&me_cl->list, &dev->me_clients);
+ up_write(&dev->me_clients_rwsem);
+}
+
+/**
+ * __mei_me_cl_by_uuid - locate me client by uuid
* increases ref count
*
* @dev: mei device
* @uuid: me client uuid
*
- * Locking: called under "dev->device_lock" lock
- *
* Return: me client or NULL if not found
+ *
+ * Locking: dev->me_clients_rwsem
*/
-struct mei_me_client *mei_me_cl_by_uuid(const struct mei_device *dev,
+static struct mei_me_client *__mei_me_cl_by_uuid(struct mei_device *dev,
const uuid_le *uuid)
{
struct mei_me_client *me_cl;
+ const uuid_le *pn;

- list_for_each_entry(me_cl, &dev->me_clients, list)
- if (uuid_le_cmp(*uuid, me_cl->props.protocol_name) == 0)
+ WARN_ON(!rwsem_is_locked(&dev->me_clients_rwsem));
+
+ list_for_each_entry(me_cl, &dev->me_clients, list) {
+ pn = &me_cl->props.protocol_name;
+ if (uuid_le_cmp(*uuid, *pn) == 0)
return mei_me_cl_get(me_cl);
+ }

return NULL;
}

/**
+ * mei_me_cl_by_uuid - locate me client by uuid
+ * increases ref count
+ *
+ * @dev: mei device
+ * @uuid: me client uuid
+ *
+ * Return: me client or NULL if not found
+ *
+ * Locking: dev->me_clients_rwsem
+ */
+struct mei_me_client *mei_me_cl_by_uuid(struct mei_device *dev,
+ const uuid_le *uuid)
+{
+ struct mei_me_client *me_cl;
+
+ down_read(&dev->me_clients_rwsem);
+ me_cl = __mei_me_cl_by_uuid(dev, uuid);
+ up_read(&dev->me_clients_rwsem);
+
+ return me_cl;
+}
+
+/**
* mei_me_cl_by_id - locate me client by client id
* increases ref count
*
* @dev: the device structure
* @client_id: me client id
*
- * Locking: called under "dev->device_lock" lock
- *
* Return: me client or NULL if not found
+ *
+ * Locking: dev->me_clients_rwsem
*/
struct mei_me_client *mei_me_cl_by_id(struct mei_device *dev, u8 client_id)
{

+ struct mei_me_client *__me_cl, *me_cl = NULL;
+
+ down_read(&dev->me_clients_rwsem);
+ list_for_each_entry(__me_cl, &dev->me_clients, list) {
+ if (__me_cl->client_id == client_id) {
+ me_cl = mei_me_cl_get(__me_cl);
+ break;
+ }
+ }
+ up_read(&dev->me_clients_rwsem);
+
+ return me_cl;
+}
+
+/**
+ * __mei_me_cl_by_uuid_id - locate me client by client id and uuid
+ * increases ref count
+ *
+ * @dev: the device structure
+ * @uuid: me client uuid
+ * @client_id: me client id
+ *
+ * Return: me client or null if not found
+ *
+ * Locking: dev->me_clients_rwsem
+ */
+static struct mei_me_client *__mei_me_cl_by_uuid_id(struct mei_device *dev,
+ const uuid_le *uuid, u8 client_id)
+{
struct mei_me_client *me_cl;
+ const uuid_le *pn;
+
+ WARN_ON(!rwsem_is_locked(&dev->me_clients_rwsem));

- list_for_each_entry(me_cl, &dev->me_clients, list)
- if (me_cl->client_id == client_id)
+ list_for_each_entry(me_cl, &dev->me_clients, list) {
+ pn = &me_cl->props.protocol_name;
+ if (uuid_le_cmp(*uuid, *pn) == 0 &&
+ me_cl->client_id == client_id)
return mei_me_cl_get(me_cl);
+ }

return NULL;
}

+
/**
* mei_me_cl_by_uuid_id - locate me client by client id and uuid
* increases ref count
@@ -135,21 +231,18 @@ struct mei_me_client *mei_me_cl_by_id(struct mei_device *dev, u8 client_id)
* @uuid: me client uuid
* @client_id: me client id
*
- * Locking: called under "dev->device_lock" lock
- *
- * Return: me client or NULL if not found
+ * Return: me client or null if not found
*/
struct mei_me_client *mei_me_cl_by_uuid_id(struct mei_device *dev,
const uuid_le *uuid, u8 client_id)
{
struct mei_me_client *me_cl;

- list_for_each_entry(me_cl, &dev->me_clients, list)
- if (uuid_le_cmp(*uuid, me_cl->props.protocol_name) == 0 &&
- me_cl->client_id == client_id)
- return mei_me_cl_get(me_cl);
+ down_read(&dev->me_clients_rwsem);
+ me_cl = __mei_me_cl_by_uuid_id(dev, uuid, client_id);
+ up_read(&dev->me_clients_rwsem);

- return NULL;
+ return me_cl;
}

/**
@@ -162,12 +255,14 @@ struct mei_me_client *mei_me_cl_by_uuid_id(struct mei_device *dev,
*/
void mei_me_cl_rm_by_uuid(struct mei_device *dev, const uuid_le *uuid)
{
- struct mei_me_client *me_cl, *next;
+ struct mei_me_client *me_cl;

dev_dbg(dev->dev, "remove %pUl\n", uuid);
- list_for_each_entry_safe(me_cl, next, &dev->me_clients, list)
- if (uuid_le_cmp(*uuid, me_cl->props.protocol_name) == 0)
- mei_me_cl_put(me_cl);
+
+ down_write(&dev->me_clients_rwsem);
+ me_cl = __mei_me_cl_by_uuid(dev, uuid);
+ __mei_me_cl_del(dev, me_cl);
+ up_write(&dev->me_clients_rwsem);
}

/**
@@ -181,15 +276,14 @@ void mei_me_cl_rm_by_uuid(struct mei_device *dev, const uuid_le *uuid)
*/
void mei_me_cl_rm_by_uuid_id(struct mei_device *dev, const uuid_le *uuid, u8 id)
{
- struct mei_me_client *me_cl, *next;
- const uuid_le *pn;
+ struct mei_me_client *me_cl;

dev_dbg(dev->dev, "remove %pUl %d\n", uuid, id);
- list_for_each_entry_safe(me_cl, next, &dev->me_clients, list) {
- pn = &me_cl->props.protocol_name;
- if (me_cl->client_id == id && uuid_le_cmp(*uuid, *pn) == 0)
- mei_me_cl_put(me_cl);
- }
+
+ down_write(&dev->me_clients_rwsem);
+ me_cl = __mei_me_cl_by_uuid_id(dev, uuid, id);
+ __mei_me_cl_del(dev, me_cl);
+ up_write(&dev->me_clients_rwsem);
}

/**
@@ -203,12 +297,12 @@ void mei_me_cl_rm_all(struct mei_device *dev)
{
struct mei_me_client *me_cl, *next;

+ down_write(&dev->me_clients_rwsem);
list_for_each_entry_safe(me_cl, next, &dev->me_clients, list)
- mei_me_cl_put(me_cl);
+ __mei_me_cl_del(dev, me_cl);
+ up_write(&dev->me_clients_rwsem);
}

-
-
/**
* mei_cl_cmp_id - tells if the clients are the same
*
@@ -535,28 +629,31 @@ int mei_cl_unlink(struct mei_cl *cl)

void mei_host_client_init(struct work_struct *work)
{
- struct mei_device *dev = container_of(work,
- struct mei_device, init_work);
+ struct mei_device *dev =
+ container_of(work, struct mei_device, init_work);
struct mei_me_client *me_cl;
- struct mei_client_properties *props;

mutex_lock(&dev->device_lock);

- list_for_each_entry(me_cl, &dev->me_clients, list) {
- props = &me_cl->props;

- if (!uuid_le_cmp(props->protocol_name, mei_amthif_guid))
- mei_amthif_host_init(dev);
- else if (!uuid_le_cmp(props->protocol_name, mei_wd_guid))
- mei_wd_host_init(dev);
- else if (!uuid_le_cmp(props->protocol_name, mei_nfc_guid))
- mei_nfc_host_init(dev);
+ me_cl = mei_me_cl_by_uuid(dev, &mei_amthif_guid);
+ if (me_cl)
+ mei_amthif_host_init(dev);
+ mei_me_cl_put(me_cl);
+
+ me_cl = mei_me_cl_by_uuid(dev, &mei_wd_guid);
+ if (me_cl)
+ mei_wd_host_init(dev);
+ mei_me_cl_put(me_cl);
+
+ me_cl = mei_me_cl_by_uuid(dev, &mei_nfc_guid);
+ if (me_cl)
+ mei_nfc_host_init(dev);
+ mei_me_cl_put(me_cl);

- }

dev->dev_state = MEI_DEV_ENABLED;
dev->reset_count = 0;
-
mutex_unlock(&dev->device_lock);

pm_runtime_mark_last_busy(dev->dev);
diff --git a/drivers/misc/mei/client.h b/drivers/misc/mei/client.h
index cfcde8e97fc4..80386f9c27e9 100644
--- a/drivers/misc/mei/client.h
+++ b/drivers/misc/mei/client.h
@@ -31,7 +31,10 @@ void mei_me_cl_init(struct mei_me_client *me_cl);
void mei_me_cl_put(struct mei_me_client *me_cl);
struct mei_me_client *mei_me_cl_get(struct mei_me_client *me_cl);

-struct mei_me_client *mei_me_cl_by_uuid(const struct mei_device *dev,
+void mei_me_cl_add(struct mei_device *dev, struct mei_me_client *me_cl);
+void mei_me_cl_del(struct mei_device *dev, struct mei_me_client *me_cl);
+
+struct mei_me_client *mei_me_cl_by_uuid(struct mei_device *dev,
const uuid_le *uuid);
struct mei_me_client *mei_me_cl_by_id(struct mei_device *dev, u8 client_id);
struct mei_me_client *mei_me_cl_by_uuid_id(struct mei_device *dev,
diff --git a/drivers/misc/mei/debugfs.c b/drivers/misc/mei/debugfs.c
index b125380ee871..50fc6635fab1 100644
--- a/drivers/misc/mei/debugfs.c
+++ b/drivers/misc/mei/debugfs.c
@@ -28,7 +28,7 @@ static ssize_t mei_dbgfs_read_meclients(struct file *fp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct mei_device *dev = fp->private_data;
- struct mei_me_client *me_cl, *n;
+ struct mei_me_client *me_cl;
size_t bufsz = 1;
char *buf;
int i = 0;
@@ -38,15 +38,14 @@ static ssize_t mei_dbgfs_read_meclients(struct file *fp, char __user *ubuf,
#define HDR \
" |id|fix| UUID |con|msg len|sb|refc|\n"

- mutex_lock(&dev->device_lock);
-
+ down_read(&dev->me_clients_rwsem);
list_for_each_entry(me_cl, &dev->me_clients, list)
bufsz++;

bufsz *= sizeof(HDR) + 1;
buf = kzalloc(bufsz, GFP_KERNEL);
if (!buf) {
- mutex_unlock(&dev->device_lock);
+ up_read(&dev->me_clients_rwsem);
return -ENOMEM;
}

@@ -56,10 +55,9 @@ static ssize_t mei_dbgfs_read_meclients(struct file *fp, char __user *ubuf,
if (dev->dev_state != MEI_DEV_ENABLED)
goto out;

- list_for_each_entry_safe(me_cl, n, &dev->me_clients, list) {
+ list_for_each_entry(me_cl, &dev->me_clients, list) {

- me_cl = mei_me_cl_get(me_cl);
- if (me_cl) {
+ if (mei_me_cl_get(me_cl)) {
pos += scnprintf(buf + pos, bufsz - pos,
"%2d|%2d|%3d|%pUl|%3d|%7d|%2d|%4d|\n",
i++, me_cl->client_id,
@@ -69,12 +67,13 @@ static ssize_t mei_dbgfs_read_meclients(struct file *fp, char __user *ubuf,
me_cl->props.max_msg_length,
me_cl->props.single_recv_buf,
atomic_read(&me_cl->refcnt.refcount));
- }

- mei_me_cl_put(me_cl);
+ mei_me_cl_put(me_cl);
+ }
}
+
out:
- mutex_unlock(&dev->device_lock);
+ up_read(&dev->me_clients_rwsem);
ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, pos);
kfree(buf);
return ret;
diff --git a/drivers/misc/mei/hbm.c b/drivers/misc/mei/hbm.c
index c8412d41e4f1..4f83e9aaa6f9 100644
--- a/drivers/misc/mei/hbm.c
+++ b/drivers/misc/mei/hbm.c
@@ -338,7 +338,8 @@ static int mei_hbm_me_cl_add(struct mei_device *dev,
me_cl->client_id = res->me_addr;
me_cl->mei_flow_ctrl_creds = 0;

- list_add(&me_cl->list, &dev->me_clients);
+ mei_me_cl_add(dev, me_cl);
+
return 0;
}

diff --git a/drivers/misc/mei/init.c b/drivers/misc/mei/init.c
index 6ad049a08e4d..ad18b0d16f61 100644
--- a/drivers/misc/mei/init.c
+++ b/drivers/misc/mei/init.c
@@ -389,6 +389,7 @@ void mei_device_init(struct mei_device *dev,
INIT_LIST_HEAD(&dev->device_list);
INIT_LIST_HEAD(&dev->me_clients);
mutex_init(&dev->device_lock);
+ init_rwsem(&dev->me_clients_rwsem);
init_waitqueue_head(&dev->wait_hw_ready);
init_waitqueue_head(&dev->wait_pg);
init_waitqueue_head(&dev->wait_hbm_start);
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index 6c6ce9381535..102cc6603eba 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -460,6 +460,7 @@ const char *mei_pg_state_str(enum mei_pg_state state);
* @version : HBM protocol version in use
* @hbm_f_pg_supported : hbm feature pgi protocol
*
+ * @me_clients_rwsem: rw lock over me_clients list
* @me_clients : list of FW clients
* @me_clients_map : FW clients bit map
* @host_clients_map : host clients id pool
@@ -556,6 +557,7 @@ struct mei_device {
struct hbm_version version;
unsigned int hbm_f_pg_supported:1;

+ struct rw_semaphore me_clients_rwsem;
struct list_head me_clients;
DECLARE_BITMAP(me_clients_map, MEI_CLIENTS_MAX);
DECLARE_BITMAP(host_clients_map, MEI_CLIENTS_MAX);
--
1.9.3


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