[char-misc-next] mei: add reference counting for me clients

From: Tomas Winkler
Date: Tue Oct 28 2014 - 08:30:35 EST

To support dynamic addition/remove we add reference
counter.

Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
---
drivers/misc/mei/amthif.c | 14 +++---
drivers/misc/mei/bus.c | 39 +++++++++------
drivers/misc/mei/client.c | 122 ++++++++++++++++++++++++++++++++++++---------
drivers/misc/mei/client.h | 6 +++
drivers/misc/mei/debugfs.c | 31 +++++++-----
drivers/misc/mei/hbm.c | 17 +++++--
drivers/misc/mei/main.c | 22 ++++----
drivers/misc/mei/mei_dev.h | 2 +
drivers/misc/mei/nfc.c | 2 +
drivers/misc/mei/wd.c | 1 +
10 files changed, 183 insertions(+), 73 deletions(-)

diff --git a/drivers/misc/mei/amthif.c b/drivers/misc/mei/amthif.c
index 56255ffe5a84..cafd9470a856 100644
--- a/drivers/misc/mei/amthif.c
+++ b/drivers/misc/mei/amthif.c
@@ -97,23 +97,25 @@ int mei_amthif_host_init(struct mei_device *dev)
/* allocate storage for ME message buffer */
msg_buf = kcalloc(dev->iamthif_mtu,
sizeof(unsigned char), GFP_KERNEL);
- if (!msg_buf)
- return -ENOMEM;
+ if (!msg_buf) {
+ ret = -ENOMEM;
+ goto out;
+ }

dev->iamthif_msg_buf = msg_buf;

ret = mei_cl_link(cl, MEI_IAMTHIF_HOST_CLIENT_ID);
-
if (ret < 0) {
- dev_err(dev->dev,
- "amthif: failed link client %d\n", ret);
- return ret;
+ dev_err(dev->dev, "amthif: failed cl_link %d\n", ret);
+ goto out;
}

ret = mei_cl_connect(cl, NULL);

dev->iamthif_state = MEI_IAMTHIF_IDLE;

+out:
+ mei_me_cl_put(me_cl);
return ret;
}

diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index b3a72bca5242..b2de93724f5b 100644
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -228,8 +228,8 @@ static int ___mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length,
bool blocking)
{
struct mei_device *dev;
- struct mei_me_client *me_cl;
- struct mei_cl_cb *cb;
+ struct mei_me_client *me_cl = NULL;
+ struct mei_cl_cb *cb = NULL;
int rets;

if (WARN_ON(!cl || !cl->dev))
@@ -237,33 +237,40 @@ static int ___mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length,

dev = cl->dev;

- if (cl->state != MEI_FILE_CONNECTED)
- return -ENODEV;
+ mutex_lock(&dev->device_lock);
+ if (cl->state != MEI_FILE_CONNECTED) {
+ rets = -ENODEV;
+ goto out;
+ }

/* Check if we have an ME client device */
me_cl = mei_me_cl_by_uuid_id(dev, &cl->cl_uuid, cl->me_client_id);
- if (!me_cl)
- return -ENOTTY;
+ if (!me_cl) {
+ rets = -ENOTTY;
+ goto out;
+ }

- if (length > me_cl->props.max_msg_length)
- return -EFBIG;
+ if (length > me_cl->props.max_msg_length) {
+ rets = -EFBIG;
+ goto out;
+ }

cb = mei_io_cb_init(cl, NULL);
- if (!cb)
- return -ENOMEM;
+ if (!cb) {
+ rets = -ENOMEM;
+ goto out;
+ }

rets = mei_io_cb_alloc_req_buf(cb, length);
- if (rets < 0) {
- mei_io_cb_free(cb);
- return rets;
- }
+ if (rets < 0)
+ goto out;

memcpy(cb->request_buffer.data, buf, length);

- mutex_lock(&dev->device_lock);
-
rets = mei_cl_write(cl, cb, blocking);

+out:
+ mei_me_cl_put(me_cl);
mutex_unlock(&dev->device_lock);
if (rets < 0)
mei_io_cb_free(cb);
diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index 03c95e06ed1b..12e7e9a0e264 100644
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -26,6 +26,57 @@
#include "hbm.h"
#include "client.h"

+
+/**
+ * mei_me_cl_init - initialize me client
+ *
+ * @me_cl: me client
+ */
+void mei_me_cl_init(struct mei_me_client *me_cl)
+{
+ INIT_LIST_HEAD(&me_cl->list);
+ kref_init(&me_cl->refcnt);
+}
+
+/**
+ * mei_me_cl_get - increase me client refcount
+ *
+ * @me_cl: me client
+ *
+ * Return: me client or NULL
+ */
+
+struct mei_me_client *mei_me_cl_get(struct mei_me_client *me_cl)
+{
+ if (me_cl)
+ kref_get(&me_cl->refcnt);
+
+ return me_cl;
+}
+
+/**
+ * mei_me_cl_release - unlink and free me client
+ *
+ * @me_cl: me client
+ */
+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
+ *
+ * @me_cl: me client
+ */
+void mei_me_cl_put(struct mei_me_client *me_cl)
+{
+ if (me_cl)
+ kref_put(&me_cl->refcnt, mei_me_cl_release);
+}
+
/**
* mei_me_cl_by_uuid - locate me client by uuid
*
@@ -43,7 +94,7 @@ struct mei_me_client *mei_me_cl_by_uuid(const struct mei_device *dev,

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

return NULL;
}
@@ -65,7 +116,8 @@ struct mei_me_client *mei_me_cl_by_id(struct mei_device *dev, u8 client_id)

list_for_each_entry(me_cl, &dev->me_clients, list)
if (me_cl->client_id == client_id)
- return me_cl;
+ return mei_me_cl_get(me_cl);
+
return NULL;
}

@@ -88,31 +140,44 @@ struct mei_me_client *mei_me_cl_by_uuid_id(struct mei_device *dev,
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 me_cl;
+ return mei_me_cl_get(me_cl);
+
return NULL;
}

/**
- * mei_me_cl_remove - remove me client matching uuid and client_id
+ * mei_me_cl_rm_by_uuid - remove all me clients matching uuid
*
* @dev: the device structure
* @uuid: me client uuid
- * @client_id: me client address
*/
-void mei_me_cl_remove(struct mei_device *dev, const uuid_le *uuid, u8 client_id)
+void mei_me_cl_rm_by_uuid(struct mei_device *dev, const uuid_le *uuid)
{
struct mei_me_client *me_cl, *next;

+ 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 &&
- me_cl->client_id == client_id) {
- list_del(&me_cl->list);
- kfree(me_cl);
- break;
- }
+ if (uuid_le_cmp(*uuid, me_cl->props.protocol_name) == 0)
+ mei_me_cl_put(me_cl);
}
}

+/**
+ * mei_me_cl_remove_by_id - remove all me clients matching client id
+ *
+ * @dev: the device structure
+ * @id: me client id
+ */
+void mei_me_cl_rm_by_id(struct mei_device *dev, u8 id)
+{
+ struct mei_me_client *me_cl, *next;
+
+ dev_dbg(dev->dev, "remove %d\n", id);
+ list_for_each_entry_safe(me_cl, next, &dev->me_clients, list) {
+ if (me_cl->client_id == id)
+ mei_me_cl_put(me_cl);
+ }
+}

/**
* mei_cl_cmp_id - tells if the clients are the same
@@ -695,6 +760,7 @@ int mei_cl_flow_ctrl_creds(struct mei_cl *cl)
{
struct mei_device *dev;
struct mei_me_client *me_cl;
+ int rets = 0;

if (WARN_ON(!cl || !cl->dev))
return -EINVAL;
@@ -710,12 +776,13 @@ int mei_cl_flow_ctrl_creds(struct mei_cl *cl)
return -ENOENT;
}

- if (me_cl->mei_flow_ctrl_creds) {
+ if (me_cl->mei_flow_ctrl_creds > 0) {
+ rets = 1;
if (WARN_ON(me_cl->props.single_recv_buf == 0))
- return -EINVAL;
- return 1;
+ rets = -EINVAL;
}
- return 0;
+ mei_me_cl_put(me_cl);
+ return rets;
}

/**
@@ -732,6 +799,7 @@ int mei_cl_flow_ctrl_reduce(struct mei_cl *cl)
{
struct mei_device *dev;
struct mei_me_client *me_cl;
+ int rets;

if (WARN_ON(!cl || !cl->dev))
return -EINVAL;
@@ -745,15 +813,22 @@ int mei_cl_flow_ctrl_reduce(struct mei_cl *cl)
}

if (me_cl->props.single_recv_buf) {
- if (WARN_ON(me_cl->mei_flow_ctrl_creds <= 0))
- return -EINVAL;
+ if (WARN_ON(me_cl->mei_flow_ctrl_creds <= 0)) {
+ rets = -EINVAL;
+ goto out;
+ }
me_cl->mei_flow_ctrl_creds--;
} else {
- if (WARN_ON(cl->mei_flow_ctrl_creds <= 0))
- return -EINVAL;
+ if (WARN_ON(cl->mei_flow_ctrl_creds <= 0)) {
+ rets = -EINVAL;
+ goto out;
+ }
cl->mei_flow_ctrl_creds--;
}
- return 0;
+ rets = 0;
+out:
+ mei_me_cl_put(me_cl);
+ return rets;
}

/**
@@ -788,6 +863,9 @@ int mei_cl_read_start(struct mei_cl *cl, size_t length)
cl_err(dev, cl, "no such me client %d\n", cl->me_client_id);
return -ENOTTY;
}
+ /* always allocate at least client max message */
+ length = max_t(size_t, length, me_cl->props.max_msg_length);
+ mei_me_cl_put(me_cl);

rets = pm_runtime_get(dev->dev);
if (rets < 0 && rets != -EINPROGRESS) {
@@ -802,8 +880,6 @@ int mei_cl_read_start(struct mei_cl *cl, size_t length)
goto out;
}

- /* always allocate at least client max message */
- length = max_t(size_t, length, me_cl->props.max_msg_length);
rets = mei_io_cb_alloc_resp_buf(cb, length);
if (rets)
goto out;
diff --git a/drivers/misc/mei/client.h b/drivers/misc/mei/client.h
index d9d0c1525259..d997b56a3fcd 100644
--- a/drivers/misc/mei/client.h
+++ b/drivers/misc/mei/client.h
@@ -34,6 +34,12 @@ struct mei_me_client *mei_me_cl_by_uuid_id(struct mei_device *dev,
void mei_me_cl_remove(struct mei_device *dev,
const uuid_le *uuid, u8 client_id);

+void mei_me_cl_rm_by_uuid(struct mei_device *dev, const uuid_le *uuid);
+void mei_me_cl_rm_by_id(struct mei_device *dev, u8 id);
+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);
+
/*
* MEI IO Functions
*/
diff --git a/drivers/misc/mei/debugfs.c b/drivers/misc/mei/debugfs.c
index b60b4263cf0f..d38a9b6a60f3 100644
--- a/drivers/misc/mei/debugfs.c
+++ b/drivers/misc/mei/debugfs.c
@@ -21,20 +21,22 @@
#include <linux/mei.h>

#include "mei_dev.h"
+#include "client.h"
#include "hw.h"

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;
+ struct mei_me_client *me_cl, *n;
size_t bufsz = 1;
char *buf;
int i = 0;
int pos = 0;
int ret;

-#define HDR " |id|fix| UUID |con|msg len|sb|\n"
+#define HDR \
+" |id|fix| UUID |con|msg len|sb|refc|\n"

mutex_lock(&dev->device_lock);

@@ -54,16 +56,21 @@ 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(me_cl, &dev->me_clients, list) {
-
- pos += scnprintf(buf + pos, bufsz - pos,
- "%2d|%2d|%3d|%pUl|%3d|%7d|%2d|\n",
- i++, me_cl->client_id,
- me_cl->props.fixed_address,
- &me_cl->props.protocol_name,
- me_cl->props.max_number_of_connections,
- me_cl->props.max_msg_length,
- me_cl->props.single_recv_buf);
+ list_for_each_entry_safe(me_cl, n, &dev->me_clients, list) {
+
+ me_cl = mei_me_cl_get(me_cl);
+ if (me_cl)
+ pos += scnprintf(buf + pos, bufsz - pos,
+ "%2d|%2d|%3d|%pUl|%3d|%7d|%2d|%4d|\n",
+ i++, me_cl->client_id,
+ me_cl->props.fixed_address,
+ &me_cl->props.protocol_name,
+ me_cl->props.max_number_of_connections,
+ me_cl->props.max_msg_length,
+ me_cl->props.single_recv_buf,
+ atomic_read(&me_cl->refcnt.refcount));
+
+ mei_me_cl_put(me_cl);
}
out:
mutex_unlock(&dev->device_lock);
diff --git a/drivers/misc/mei/hbm.c b/drivers/misc/mei/hbm.c
index 49a2653d91a5..65a505226222 100644
--- a/drivers/misc/mei/hbm.c
+++ b/drivers/misc/mei/hbm.c
@@ -339,11 +339,16 @@ static int mei_hbm_me_cl_add(struct mei_device *dev,
struct hbm_props_response *res)
{
struct mei_me_client *me_cl;
+ const uuid_le *uuid = &res->client_properties.protocol_name;
+
+ mei_me_cl_rm_by_uuid(dev, uuid);

me_cl = kzalloc(sizeof(struct mei_me_client), GFP_KERNEL);
if (!me_cl)
return -ENOMEM;

+ mei_me_cl_init(me_cl);
+
me_cl->props = res->client_properties;
me_cl->client_id = res->me_addr;
me_cl->mei_flow_ctrl_creds = 0;
@@ -484,6 +489,7 @@ static int mei_hbm_add_single_flow_creds(struct mei_device *dev,
struct hbm_flow_control *flow)
{
struct mei_me_client *me_cl;
+ int rets;

me_cl = mei_me_cl_by_id(dev, flow->me_addr);
if (!me_cl) {
@@ -492,14 +498,19 @@ static int mei_hbm_add_single_flow_creds(struct mei_device *dev,
return -ENOENT;
}

- if (WARN_ON(me_cl->props.single_recv_buf == 0))
- return -EINVAL;
+ if (WARN_ON(me_cl->props.single_recv_buf == 0)) {
+ rets = -EINVAL;
+ goto out;
+ }

me_cl->mei_flow_ctrl_creds++;
dev_dbg(dev->dev, "recv flow ctrl msg ME %d (single) creds = %d.\n",
flow->me_addr, me_cl->mei_flow_ctrl_creds);

- return 0;
+ rets = 0;
+out:
+ mei_me_cl_put(me_cl);
+ return rets;
}

/**
diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index beedc91f03a6..5d6a15c3619a 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -303,7 +303,7 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
size_t length, loff_t *offset)
{
struct mei_cl *cl = file->private_data;
- struct mei_me_client *me_cl;
+ struct mei_me_client *me_cl = NULL;
struct mei_cl_cb *write_cb = NULL;
struct mei_device *dev;
unsigned long timeout = 0;
@@ -399,12 +399,14 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
"amthif write failed with status = %d\n", rets);
goto out;
}
+ mei_me_cl_put(me_cl);
mutex_unlock(&dev->device_lock);
return length;
}

rets = mei_cl_write(cl, write_cb, false);
out:
+ mei_me_cl_put(me_cl);
mutex_unlock(&dev->device_lock);
if (rets < 0)
mei_io_cb_free(write_cb);
@@ -433,24 +435,19 @@ static int mei_ioctl_connect_client(struct file *file,
cl = file->private_data;
dev = cl->dev;

- if (dev->dev_state != MEI_DEV_ENABLED) {
- rets = -ENODEV;
- goto end;
- }
+ if (dev->dev_state != MEI_DEV_ENABLED)
+ return -ENODEV;

if (cl->state != MEI_FILE_INITIALIZING &&
- cl->state != MEI_FILE_DISCONNECTED) {
- rets = -EBUSY;
- goto end;
- }
+ cl->state != MEI_FILE_DISCONNECTED)
+ return -EBUSY;

/* find ME client we're trying to connect to */
me_cl = mei_me_cl_by_uuid(dev, &data->in_client_uuid);
if (!me_cl || me_cl->props.fixed_address) {
dev_dbg(dev->dev, "Cannot connect to FW Client UUID = %pUl\n",
&data->in_client_uuid);
- rets = -ENOTTY;
- goto end;
+ return -ENOTTY;
}

cl->me_client_id = me_cl->client_id;
@@ -487,17 +484,16 @@ static int mei_ioctl_connect_client(struct file *file,
goto end;
}

-
/* prepare the output buffer */
client = &data->out_client_properties;
client->max_msg_length = me_cl->props.max_msg_length;
client->protocol_version = me_cl->props.protocol_version;
dev_dbg(dev->dev, "Can connect?\n");

-
rets = mei_cl_connect(cl, file);

end:
+ mei_me_cl_put(me_cl);
return rets;
}

diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index 1288a5cf60b9..7d3a1de0b051 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -169,12 +169,14 @@ struct mei_fw_status {
* struct mei_me_client - representation of me (fw) client
*
* @list: link in me client list
+ * @refcnt: struct reference count
* @props: client properties
* @client_id: me client id
* @mei_flow_ctrl_creds: flow control credits
*/
struct mei_me_client {
struct list_head list;
+ struct kref refcnt;
struct mei_client_properties props;
u8 client_id;
u8 mei_flow_ctrl_creds;
diff --git a/drivers/misc/mei/nfc.c b/drivers/misc/mei/nfc.c
index 82f38613c550..a10f3250aa2c 100644
--- a/drivers/misc/mei/nfc.c
+++ b/drivers/misc/mei/nfc.c
@@ -513,6 +513,7 @@ int mei_nfc_host_init(struct mei_device *dev)

cl_info->me_client_id = me_cl->client_id;
cl_info->cl_uuid = me_cl->props.protocol_name;
+ mei_me_cl_put(me_cl);

ret = mei_cl_link(cl_info, MEI_HOST_CLIENT_ID_ANY);
if (ret)
@@ -531,6 +532,7 @@ int mei_nfc_host_init(struct mei_device *dev)

cl->me_client_id = me_cl->client_id;
cl->cl_uuid = me_cl->props.protocol_name;
+ mei_me_cl_put(me_cl);

ret = mei_cl_link(cl, MEI_HOST_CLIENT_ID_ANY);
if (ret)
diff --git a/drivers/misc/mei/wd.c b/drivers/misc/mei/wd.c
index b1d892cea94d..475f1dea45bf 100644
--- a/drivers/misc/mei/wd.c
+++ b/drivers/misc/mei/wd.c
@@ -76,6 +76,7 @@ int mei_wd_host_init(struct mei_device *dev)

cl->me_client_id = me_cl->client_id;
cl->cl_uuid = me_cl->props.protocol_name;
+ mei_me_cl_put(me_cl);

ret = mei_cl_link(cl, MEI_WD_HOST_CLIENT_ID);

--
1.9.3

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