[char-misc-next 07/13] mei: add a vtag map for each client

From: Tomas Winkler
Date: Tue Aug 18 2020 - 08:10:55 EST


From: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>

Vtag map is a list of tuples of vtag and file pointer (struct
mei_cl_vtag) associated with a particular me host client.

Signed-off-by: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
---
drivers/misc/mei/client.c | 168 ++++++++++++++++++++++++++++++++++++-
drivers/misc/mei/client.h | 3 +
drivers/misc/mei/main.c | 68 ++++++++++++++-
drivers/misc/mei/mei_dev.h | 17 ++++
4 files changed, 251 insertions(+), 5 deletions(-)

diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index 276021f99666..3904fce18261 100644
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -354,6 +354,27 @@ static inline void mei_tx_cb_dequeue(struct mei_cl_cb *cb)
mei_io_cb_free(cb);
}

+/**
+ * mei_cl_set_read_by_fp - set pending_read flag to vtag struct for given fp
+ *
+ * Locking: called under "dev->device_lock" lock
+ *
+ * @cl: mei client
+ * @fp: pointer to file structure
+ */
+static void mei_cl_set_read_by_fp(const struct mei_cl *cl,
+ const struct file *fp)
+{
+ struct mei_cl_vtag *cl_vtag;
+
+ list_for_each_entry(cl_vtag, &cl->vtag_map, list) {
+ if (cl_vtag->fp == fp) {
+ cl_vtag->pending_read = true;
+ return;
+ }
+ }
+}
+
/**
* mei_io_cb_init - allocate and initialize io callback
*
@@ -435,6 +456,19 @@ static void mei_io_list_free_fp(struct list_head *head, const struct file *fp)
mei_io_cb_free(cb);
}

+/**
+ * mei_cl_free_pending - free pending cb
+ *
+ * @cl: host client
+ */
+static void mei_cl_free_pending(struct mei_cl *cl)
+{
+ struct mei_cl_cb *cb;
+
+ cb = list_first_entry_or_null(&cl->rd_pending, struct mei_cl_cb, list);
+ mei_io_cb_free(cb);
+}
+
/**
* mei_cl_alloc_cb - a convenient wrapper for allocating read cb
*
@@ -544,7 +578,9 @@ int mei_cl_flush_queues(struct mei_cl *cl, const struct file *fp)
mei_io_tx_list_free_cl(&cl->dev->write_waiting_list, cl);
mei_io_list_flush_cl(&cl->dev->ctrl_wr_list, cl);
mei_io_list_flush_cl(&cl->dev->ctrl_rd_list, cl);
- mei_io_list_free_fp(&cl->rd_pending, fp);
+ /* free pending cb only in final flush */
+ if (!fp)
+ mei_cl_free_pending(cl);
spin_lock(&cl->rd_completed_lock);
mei_io_list_free_fp(&cl->rd_completed, fp);
spin_unlock(&cl->rd_completed_lock);
@@ -565,6 +601,7 @@ static void mei_cl_init(struct mei_cl *cl, struct mei_device *dev)
init_waitqueue_head(&cl->rx_wait);
init_waitqueue_head(&cl->tx_wait);
init_waitqueue_head(&cl->ev_wait);
+ INIT_LIST_HEAD(&cl->vtag_map);
spin_lock_init(&cl->rd_completed_lock);
INIT_LIST_HEAD(&cl->rd_completed);
INIT_LIST_HEAD(&cl->rd_pending);
@@ -1237,8 +1274,117 @@ static int mei_cl_tx_flow_ctrl_creds_reduce(struct mei_cl *cl)
return 0;
}

+/**
+ * mei_cl_vtag_alloc - allocate and fill the vtag structure
+ *
+ * @fp: pointer to file structure
+ * @vtag: vm tag
+ *
+ * Return:
+ * * Pointer to allocated struct - on success
+ * * ERR_PTR(-ENOMEM) on memory allocation failure
+ */
+struct mei_cl_vtag *mei_cl_vtag_alloc(struct file *fp, u8 vtag)
+{
+ struct mei_cl_vtag *cl_vtag;
+
+ cl_vtag = kzalloc(sizeof(*cl_vtag), GFP_KERNEL);
+ if (!cl_vtag)
+ return ERR_PTR(-ENOMEM);
+
+ INIT_LIST_HEAD(&cl_vtag->list);
+ cl_vtag->vtag = vtag;
+ cl_vtag->fp = fp;
+
+ return cl_vtag;
+}
+
+/**
+ * mei_cl_fp_by_vtag - obtain the file pointer by vtag
+ *
+ * @cl: host client
+ * @vtag: vm tag
+ *
+ * Return:
+ * * A file pointer - on success
+ * * ERR_PTR(-ENOENT) if vtag is not found in the client vtag list
+ */
+const struct file *mei_cl_fp_by_vtag(const struct mei_cl *cl, u8 vtag)
+{
+ struct mei_cl_vtag *vtag_l;
+
+ list_for_each_entry(vtag_l, &cl->vtag_map, list)
+ if (vtag_l->vtag == vtag)
+ return vtag_l->fp;
+
+ return ERR_PTR(-ENOENT);
+}
+
+/**
+ * mei_cl_reset_read_by_vtag - reset pending_read flag by given vtag
+ *
+ * @cl: host client
+ * @vtag: vm tag
+ */
+static void mei_cl_reset_read_by_vtag(const struct mei_cl *cl, u8 vtag)
+{
+ struct mei_cl_vtag *vtag_l;
+
+ list_for_each_entry(vtag_l, &cl->vtag_map, list) {
+ if (vtag_l->vtag == vtag) {
+ vtag_l->pending_read = false;
+ break;
+ }
+ }
+}
+
+/**
+ * mei_cl_read_vtag_add_fc - add flow control for next pending reader
+ * in the vtag list
+ *
+ * @cl: host client
+ */
+static void mei_cl_read_vtag_add_fc(struct mei_cl *cl)
+{
+ struct mei_cl_vtag *cl_vtag;
+
+ list_for_each_entry(cl_vtag, &cl->vtag_map, list) {
+ if (cl_vtag->pending_read) {
+ if (mei_cl_enqueue_ctrl_wr_cb(cl,
+ mei_cl_mtu(cl),
+ MEI_FOP_READ,
+ cl_vtag->fp))
+ cl->rx_flow_ctrl_creds++;
+ break;
+ }
+ }
+}
+
+/**
+ * mei_cl_vt_support_check - check if client support vtags
+ *
+ * @cl: host client
+ *
+ * Return:
+ * * 0 - supported, or not connected at all
+ * * -EOPNOTSUPP - vtags are not supported by client
+ */
+int mei_cl_vt_support_check(const struct mei_cl *cl)
+{
+ struct mei_device *dev = cl->dev;
+
+ if (!dev->hbm_f_vt_supported)
+ return -EOPNOTSUPP;
+
+ if (!cl->me_cl)
+ return 0;
+
+ return cl->me_cl->props.vt_supported ? 0 : -EOPNOTSUPP;
+}
+
/**
* mei_cl_add_rd_completed - add read completed callback to list with lock
+ * and vtag check
*
* @cl: host client
* @cb: callback block
@@ -1246,6 +1392,20 @@ static int mei_cl_tx_flow_ctrl_creds_reduce(struct mei_cl *cl)
*/
void mei_cl_add_rd_completed(struct mei_cl *cl, struct mei_cl_cb *cb)
{
+ const struct file *fp;
+
+ if (!mei_cl_vt_support_check(cl)) {
+ fp = mei_cl_fp_by_vtag(cl, cb->vtag);
+ if (IS_ERR(fp)) {
+ /* client already disconnected, discarding */
+ mei_io_cb_free(cb);
+ return;
+ }
+ cb->fp = fp;
+ mei_cl_reset_read_by_vtag(cl, cb->vtag);
+ mei_cl_read_vtag_add_fc(cl);
+ }
+
spin_lock(&cl->rd_completed_lock);
list_add_tail(&cb->list, &cl->rd_completed);
spin_unlock(&cl->rd_completed_lock);
@@ -1520,13 +1680,17 @@ int mei_cl_read_start(struct mei_cl *cl, size_t length, const struct file *fp)
return 0;

/* HW currently supports only one pending read */
- if (cl->rx_flow_ctrl_creds)
+ if (cl->rx_flow_ctrl_creds) {
+ mei_cl_set_read_by_fp(cl, fp);
return -EBUSY;
+ }

cb = mei_cl_enqueue_ctrl_wr_cb(cl, length, MEI_FOP_READ, fp);
if (!cb)
return -ENOMEM;

+ mei_cl_set_read_by_fp(cl, fp);
+
rets = pm_runtime_get(dev->dev);
if (rets < 0 && rets != -EINPROGRESS) {
pm_runtime_put_noidle(dev->dev);
diff --git a/drivers/misc/mei/client.h b/drivers/misc/mei/client.h
index bd57c64f6c1a..64143d4ec758 100644
--- a/drivers/misc/mei/client.h
+++ b/drivers/misc/mei/client.h
@@ -146,6 +146,9 @@ struct mei_cl_cb *mei_cl_enqueue_ctrl_wr_cb(struct mei_cl *cl, size_t length,
const struct file *fp);
int mei_cl_flush_queues(struct mei_cl *cl, const struct file *fp);

+struct mei_cl_vtag *mei_cl_vtag_alloc(struct file *fp, u8 vtag);
+const struct file *mei_cl_fp_by_vtag(const struct mei_cl *cl, u8 vtag);
+int mei_cl_vt_support_check(const struct mei_cl *cl);
/*
* MEI input output function prototype
*/
diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index 441bdea4d4c1..401bf8743689 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -80,6 +80,27 @@ static int mei_open(struct inode *inode, struct file *file)
return err;
}

+/**
+ * mei_cl_vtag_remove_by_fp - remove vtag that corresponds to fp from list
+ *
+ * @cl: host client
+ * @fp: pointer to file structure
+ *
+ */
+static void mei_cl_vtag_remove_by_fp(const struct mei_cl *cl,
+ const struct file *fp)
+{
+ struct mei_cl_vtag *vtag_l, *next;
+
+ list_for_each_entry_safe(vtag_l, next, &cl->vtag_map, list) {
+ if (vtag_l->fp == fp) {
+ list_del(&vtag_l->list);
+ kfree(vtag_l);
+ return;
+ }
+ }
+}
+
/**
* mei_release - the release function
*
@@ -101,17 +122,35 @@ static int mei_release(struct inode *inode, struct file *file)

mutex_lock(&dev->device_lock);

+ mei_cl_vtag_remove_by_fp(cl, file);
+
+ if (!list_empty(&cl->vtag_map)) {
+ cl_dbg(dev, cl, "not the last vtag\n");
+ mei_cl_flush_queues(cl, file);
+ rets = 0;
+ goto out;
+ }
+
rets = mei_cl_disconnect(cl);
+ /*
+ * Check again: This is necessary since disconnect releases the lock
+ * and another client can connect in the meantime.
+ */
+ if (!list_empty(&cl->vtag_map)) {
+ cl_dbg(dev, cl, "not the last vtag after disconnect\n");
+ mei_cl_flush_queues(cl, file);
+ goto out;
+ }

- mei_cl_flush_queues(cl, file);
+ mei_cl_flush_queues(cl, NULL);
cl_dbg(dev, cl, "removing\n");

mei_cl_unlink(cl);
+ kfree(cl);

+out:
file->private_data = NULL;

- kfree(cl);
-
mutex_unlock(&dev->device_lock);
return rets;
}
@@ -237,6 +276,28 @@ static ssize_t mei_read(struct file *file, char __user *ubuf,
mutex_unlock(&dev->device_lock);
return rets;
}
+
+/**
+ * mei_cl_vtag_by_fp - obtain the vtag by file pointer
+ *
+ * @cl: host client
+ * @fp: pointer to file structure
+ *
+ * Return: vtag value on success, otherwise 0
+ */
+static u8 mei_cl_vtag_by_fp(const struct mei_cl *cl, const struct file *fp)
+{
+ struct mei_cl_vtag *cl_vtag;
+
+ if (!fp)
+ return 0;
+
+ list_for_each_entry(cl_vtag, &cl->vtag_map, list)
+ if (cl_vtag->fp == fp)
+ return cl_vtag->vtag;
+ return 0;
+}
+
/**
* mei_write - the write function.
*
@@ -314,6 +375,7 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
rets = -ENOMEM;
goto out;
}
+ cb->vtag = mei_cl_vtag_by_fp(cl, file);

rets = copy_from_user(cb->buf.data, ubuf, length);
if (rets) {
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index 1219edea3243..2f4cc1a8aae8 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -193,6 +193,21 @@ struct mei_cl_cb {
u32 blocking:1;
};

+/**
+ * struct mei_cl_vtag - file pointer to vtag mapping structure
+ *
+ * @list: link in map queue
+ * @fp: file pointer
+ * @vtag: corresponding vtag
+ * @pending_read: the read is pending on this file
+ */
+struct mei_cl_vtag {
+ struct list_head list;
+ const struct file *fp;
+ u8 vtag;
+ u8 pending_read:1;
+};
+
/**
* struct mei_cl - me client host representation
* carried in file->private_data
@@ -209,6 +224,7 @@ struct mei_cl_cb {
* @me_cl: fw client connected
* @fp: file associated with client
* @host_client_id: host id
+ * @vtag_map: vtag map
* @tx_flow_ctrl_creds: transmit flow credentials
* @rx_flow_ctrl_creds: receive flow credentials
* @timer_count: watchdog timer for operation completion
@@ -235,6 +251,7 @@ struct mei_cl {
struct mei_me_client *me_cl;
const struct file *fp;
u8 host_client_id;
+ struct list_head vtag_map;
u8 tx_flow_ctrl_creds;
u8 rx_flow_ctrl_creds;
u8 timer_count;
--
2.25.4