mei: add reference counting for me clients
authorTomas Winkler <tomas.winkler@intel.com>
Sat, 10 Jan 2015 22:07:16 +0000 (00:07 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 25 Jan 2015 17:17:56 +0000 (09:17 -0800)
To support dynamic addition and removal of
me clients we add reference counter.

Update kdoc with locking requirements.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/misc/mei/amthif.c
drivers/misc/mei/bus.c
drivers/misc/mei/client.c
drivers/misc/mei/client.h
drivers/misc/mei/debugfs.c
drivers/misc/mei/hbm.c
drivers/misc/mei/main.c
drivers/misc/mei/mei_dev.h
drivers/misc/mei/nfc.c
drivers/misc/mei/wd.c

index 79f53941779d1f321d96ac6b6727cb13e4d5ded0..c4cb9a984a5fb3965bba581eab0dd5c9096ec851 100644 (file)
@@ -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;
 }
 
index 31164dd14bd0d81337839d0d30ab85d0f0d5ec7b..be767f4db26a137bb93043bf448891031428e9fe 100644 (file)
@@ -228,8 +228,8 @@ static ssize_t ___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;
        ssize_t rets;
 
        if (WARN_ON(!cl || !cl->dev))
@@ -237,33 +237,40 @@ static ssize_t ___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);
index 3be18b7951e5fd43dc4014ed7f3fc97e994f3c0d..dfbddfe1c7a06f9e1ea435ffac42ab31b7a9511c 100644 (file)
 #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 - increases me client refcount
+ *
+ * @me_cl: me client
+ *
+ * Locking: called under "dev->device_lock" lock
+ *
+ * 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
+ *
+ * Locking: called under "dev->device_lock" lock
+ *
+ * @ref: me_client refcount
+ */
+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
+ *
+ * Locking: called under "dev->device_lock" lock
+ *
+ * @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
+ *     increases ref count
  *
  * @dev: mei device
  * @uuid: me client uuid
@@ -43,13 +99,14 @@ 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;
 }
 
 /**
  * mei_me_cl_by_id - locate me client by client id
+ *     increases ref count
  *
  * @dev: the device structure
  * @client_id: me client id
@@ -65,12 +122,14 @@ 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;
 }
 
 /**
  * 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
@@ -88,31 +147,67 @@ 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
+ *
+ * Locking: called under "dev->device_lock" lock
  */
-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)
+                       mei_me_cl_put(me_cl);
+}
+
+/**
+ * mei_me_cl_rm_by_uuid_id - remove all me clients matching client id
+ *
+ * @dev: the device structure
+ * @uuid: me client uuid
+ * @id: me client id
+ *
+ * Locking: called under "dev->device_lock" lock
+ */
+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;
+
+       dev_dbg(dev->dev, "remove %pUl %d\n", uuid, id);
        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;
-               }
+               pn =  &me_cl->props.protocol_name;
+               if (me_cl->client_id == id && uuid_le_cmp(*uuid, *pn) == 0)
+                       mei_me_cl_put(me_cl);
        }
 }
 
+/**
+ * mei_me_cl_rm_all - remove all me clients
+ *
+ * @dev: the device structure
+ *
+ * Locking: called under "dev->device_lock" lock
+ */
+void mei_me_cl_rm_all(struct mei_device *dev)
+{
+       struct mei_me_client *me_cl, *next;
+
+       list_for_each_entry_safe(me_cl, next, &dev->me_clients, list)
+                       mei_me_cl_put(me_cl);
+}
+
+
 
 /**
  * mei_cl_cmp_id - tells if the clients are the same
@@ -695,6 +790,7 @@ 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 +806,13 @@ 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 +829,7 @@ 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 +843,22 @@ 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 +893,9 @@ 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 +910,6 @@ 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;
index d9d0c1525259978b93c8866069bc24f31cac78a3..cfcde8e97fc489a3e0ba966d06def8f1fde2c0c4 100644 (file)
 
 #include "mei_dev.h"
 
+/*
+ * reference counting base function
+ */
+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,
-                                       const uuid_le *cuuid);
+                                       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,
                                           const uuid_le *uuid, u8 client_id);
-
-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_uuid_id(struct mei_device *dev,
+                            const uuid_le *uuid, u8 id);
+void mei_me_cl_rm_all(struct mei_device *dev);
 
 /*
  * MEI IO Functions
index b60b4263cf0f989a15733918c22fb53f0fface51..b125380ee8710162923bc246e0712bfca6d92690 100644 (file)
 #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 +56,22 @@ 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);
index 239d7f5d6a92a851b48e381e5db05c9e94eb1c0f..c8412d41e4f163410b771dfcdd7126f201f3e937 100644 (file)
@@ -104,21 +104,6 @@ void mei_hbm_idle(struct mei_device *dev)
        dev->hbm_state = MEI_HBM_IDLE;
 }
 
-/**
- * mei_me_cl_remove_all - remove all me clients
- *
- * @dev: the device structure
- */
-static void mei_me_cl_remove_all(struct mei_device *dev)
-{
-       struct mei_me_client *me_cl, *next;
-
-       list_for_each_entry_safe(me_cl, next, &dev->me_clients, list) {
-                       list_del(&me_cl->list);
-                       kfree(me_cl);
-       }
-}
-
 /**
  * mei_hbm_reset - reset hbm counters and book keeping data structurs
  *
@@ -128,7 +113,7 @@ void mei_hbm_reset(struct mei_device *dev)
 {
        dev->me_client_index = 0;
 
-       mei_me_cl_remove_all(dev);
+       mei_me_cl_rm_all(dev);
 
        mei_hbm_idle(dev);
 }
@@ -339,11 +324,16 @@ 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 +474,7 @@ 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 +483,19 @@ 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;
 }
 
 /**
index ae56ba6ca0e3615758953259c4223efab7322613..3c019c0e60eb859ede0621f26c4d71d72fca8abe 100644 (file)
@@ -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;
 }
 
index 7f350af2ee10b201629659f6d5afcd8959824c87..6c6ce9381535151a437612ad83bae65b08dfed2e 100644 (file)
@@ -172,12 +172,14 @@ 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;
index 60ca9240368e525e48bf13b0f0bb79fdf758d6f1..bb61a119b8bbb4fdd8ee7d09da5fb520bab72573 100644 (file)
@@ -521,6 +521,7 @@ 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)
@@ -539,6 +540,7 @@ 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)
index b1d892cea94da2f0733670392429fa09bb1a58ed..475f1dea45bfd06c5ecfa9e2fdb40da2da32b34f 100644 (file)
@@ -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);