[char-misc-next 2/2] mei: drop wr_msg from the mei_dev structure

From: Tomas Winkler
Date: Sun May 08 2016 - 17:09:44 EST

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In reply to: Tomas Winkler: "[char-misc-next 1/2] mei: don't use wake_up_interruptible for wr_ctrl"
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From: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>

The control messages are usually small, around 8 bytes, and can be
allocated on the stack.
Using on stack allocation allows us to drop 'wr_msg' a rather large
buffer reserved in the mei_dev structure and relax contention
of this device global buffer.

Signed-off-by: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
---
drivers/misc/mei/hbm.c | 137 ++++++++++++++++++++++-----------------------
drivers/misc/mei/mei_dev.h | 10 +---
2 files changed, 68 insertions(+), 79 deletions(-)

diff --git a/drivers/misc/mei/hbm.c b/drivers/misc/mei/hbm.c
index 5aa606c8a827..085f3aafe6fa 100644
--- a/drivers/misc/mei/hbm.c
+++ b/drivers/misc/mei/hbm.c
@@ -132,6 +132,7 @@ static inline void mei_hbm_hdr(struct mei_msg_hdr *hdr, size_t length)
hdr->length = length;
hdr->msg_complete = 1;
hdr->reserved = 0;
+ hdr->internal = 0;
}

/**
@@ -165,15 +166,15 @@ void mei_hbm_cl_hdr(struct mei_cl *cl, u8 hbm_cmd, void *buf, size_t len)
* Return: 0 on success, <0 on failure.
*/
static inline
-int mei_hbm_cl_write(struct mei_device *dev,
- struct mei_cl *cl, u8 hbm_cmd, size_t len)
+int mei_hbm_cl_write(struct mei_device *dev, struct mei_cl *cl,
+ u8 hbm_cmd, u8 *buf, size_t len)
{
- struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
+ struct mei_msg_hdr mei_hdr;

- mei_hbm_hdr(mei_hdr, len);
- mei_hbm_cl_hdr(cl, hbm_cmd, dev->wr_msg.data, len);
+ mei_hbm_hdr(&mei_hdr, len);
+ mei_hbm_cl_hdr(cl, hbm_cmd, buf, len);

- return mei_write_message(dev, mei_hdr, dev->wr_msg.data);
+ return mei_write_message(dev, &mei_hdr, buf);
}

/**
@@ -250,24 +251,23 @@ int mei_hbm_start_wait(struct mei_device *dev)
*/
int mei_hbm_start_req(struct mei_device *dev)
{
- struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
- struct hbm_host_version_request *start_req;
+ struct mei_msg_hdr mei_hdr;
+ struct hbm_host_version_request start_req;
const size_t len = sizeof(struct hbm_host_version_request);
int ret;

mei_hbm_reset(dev);

- mei_hbm_hdr(mei_hdr, len);
+ mei_hbm_hdr(&mei_hdr, len);

/* host start message */
- start_req = (struct hbm_host_version_request *)dev->wr_msg.data;
- memset(start_req, 0, len);
- start_req->hbm_cmd = HOST_START_REQ_CMD;
- start_req->host_version.major_version = HBM_MAJOR_VERSION;
- start_req->host_version.minor_version = HBM_MINOR_VERSION;
+ memset(&start_req, 0, len);
+ start_req.hbm_cmd = HOST_START_REQ_CMD;
+ start_req.host_version.major_version = HBM_MAJOR_VERSION;
+ start_req.host_version.minor_version = HBM_MINOR_VERSION;

dev->hbm_state = MEI_HBM_IDLE;
- ret = mei_write_message(dev, mei_hdr, dev->wr_msg.data);
+ ret = mei_write_message(dev, &mei_hdr, &start_req);
if (ret) {
dev_err(dev->dev, "version message write failed: ret = %d\n",
ret);
@@ -288,23 +288,22 @@ int mei_hbm_start_req(struct mei_device *dev)
*/
static int mei_hbm_enum_clients_req(struct mei_device *dev)
{
- struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
- struct hbm_host_enum_request *enum_req;
+ struct mei_msg_hdr mei_hdr;
+ struct hbm_host_enum_request enum_req;
const size_t len = sizeof(struct hbm_host_enum_request);
int ret;

/* enumerate clients */
- mei_hbm_hdr(mei_hdr, len);
+ mei_hbm_hdr(&mei_hdr, len);

- enum_req = (struct hbm_host_enum_request *)dev->wr_msg.data;
- memset(enum_req, 0, len);
- enum_req->hbm_cmd = HOST_ENUM_REQ_CMD;
- enum_req->flags |= dev->hbm_f_dc_supported ?
- MEI_HBM_ENUM_F_ALLOW_ADD : 0;
- enum_req->flags |= dev->hbm_f_ie_supported ?
- MEI_HBM_ENUM_F_IMMEDIATE_ENUM : 0;
+ memset(&enum_req, 0, len);
+ enum_req.hbm_cmd = HOST_ENUM_REQ_CMD;
+ enum_req.flags |= dev->hbm_f_dc_supported ?
+ MEI_HBM_ENUM_F_ALLOW_ADD : 0;
+ enum_req.flags |= dev->hbm_f_ie_supported ?
+ MEI_HBM_ENUM_F_IMMEDIATE_ENUM : 0;

- ret = mei_write_message(dev, mei_hdr, dev->wr_msg.data);
+ ret = mei_write_message(dev, &mei_hdr, &enum_req);
if (ret) {
dev_err(dev->dev, "enumeration request write failed: ret = %d.\n",
ret);
@@ -358,23 +357,21 @@ static int mei_hbm_me_cl_add(struct mei_device *dev,
*/
static int mei_hbm_add_cl_resp(struct mei_device *dev, u8 addr, u8 status)
{
- struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
- struct hbm_add_client_response *resp;
+ struct mei_msg_hdr mei_hdr;
+ struct hbm_add_client_response resp;
const size_t len = sizeof(struct hbm_add_client_response);
int ret;

dev_dbg(dev->dev, "adding client response\n");

- resp = (struct hbm_add_client_response *)dev->wr_msg.data;
+ mei_hbm_hdr(&mei_hdr, len);

- mei_hbm_hdr(mei_hdr, len);
- memset(resp, 0, sizeof(struct hbm_add_client_response));
+ memset(&resp, 0, sizeof(struct hbm_add_client_response));
+ resp.hbm_cmd = MEI_HBM_ADD_CLIENT_RES_CMD;
+ resp.me_addr = addr;
+ resp.status = status;

- resp->hbm_cmd = MEI_HBM_ADD_CLIENT_RES_CMD;
- resp->me_addr = addr;
- resp->status = status;
-
- ret = mei_write_message(dev, mei_hdr, dev->wr_msg.data);
+ ret = mei_write_message(dev, &mei_hdr, &resp);
if (ret)
dev_err(dev->dev, "add client response write failed: ret = %d\n",
ret);
@@ -421,18 +418,17 @@ int mei_hbm_cl_notify_req(struct mei_device *dev,
struct mei_cl *cl, u8 start)
{

- struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
- struct hbm_notification_request *req;
+ struct mei_msg_hdr mei_hdr;
+ struct hbm_notification_request req;
const size_t len = sizeof(struct hbm_notification_request);
int ret;

- mei_hbm_hdr(mei_hdr, len);
- mei_hbm_cl_hdr(cl, MEI_HBM_NOTIFY_REQ_CMD, dev->wr_msg.data, len);
+ mei_hbm_hdr(&mei_hdr, len);
+ mei_hbm_cl_hdr(cl, MEI_HBM_NOTIFY_REQ_CMD, &req, len);

- req = (struct hbm_notification_request *)dev->wr_msg.data;
- req->start = start;
+ req.start = start;

- ret = mei_write_message(dev, mei_hdr, dev->wr_msg.data);
+ ret = mei_write_message(dev, &mei_hdr, &req);
if (ret)
dev_err(dev->dev, "notify request failed: ret = %d\n", ret);

@@ -534,8 +530,8 @@ static void mei_hbm_cl_notify(struct mei_device *dev,
*/
static int mei_hbm_prop_req(struct mei_device *dev, unsigned long start_idx)
{
- struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
- struct hbm_props_request *prop_req;
+ struct mei_msg_hdr mei_hdr;
+ struct hbm_props_request prop_req;
const size_t len = sizeof(struct hbm_props_request);
unsigned long addr;
int ret;
@@ -550,15 +546,14 @@ static int mei_hbm_prop_req(struct mei_device *dev, unsigned long start_idx)
return 0;
}

- mei_hbm_hdr(mei_hdr, len);
- prop_req = (struct hbm_props_request *)dev->wr_msg.data;
+ mei_hbm_hdr(&mei_hdr, len);

- memset(prop_req, 0, sizeof(struct hbm_props_request));
+ memset(&prop_req, 0, sizeof(struct hbm_props_request));

- prop_req->hbm_cmd = HOST_CLIENT_PROPERTIES_REQ_CMD;
- prop_req->me_addr = addr;
+ prop_req.hbm_cmd = HOST_CLIENT_PROPERTIES_REQ_CMD;
+ prop_req.me_addr = addr;

- ret = mei_write_message(dev, mei_hdr, dev->wr_msg.data);
+ ret = mei_write_message(dev, &mei_hdr, &prop_req);
if (ret) {
dev_err(dev->dev, "properties request write failed: ret = %d\n",
ret);
@@ -581,21 +576,20 @@ static int mei_hbm_prop_req(struct mei_device *dev, unsigned long start_idx)
*/
int mei_hbm_pg(struct mei_device *dev, u8 pg_cmd)
{
- struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
- struct hbm_power_gate *req;
+ struct mei_msg_hdr mei_hdr;
+ struct hbm_power_gate req;
const size_t len = sizeof(struct hbm_power_gate);
int ret;

if (!dev->hbm_f_pg_supported)
return -EOPNOTSUPP;

- mei_hbm_hdr(mei_hdr, len);
+ mei_hbm_hdr(&mei_hdr, len);

- req = (struct hbm_power_gate *)dev->wr_msg.data;
- memset(req, 0, len);
- req->hbm_cmd = pg_cmd;
+ memset(&req, 0, len);
+ req.hbm_cmd = pg_cmd;

- ret = mei_write_message(dev, mei_hdr, dev->wr_msg.data);
+ ret = mei_write_message(dev, &mei_hdr, &req);
if (ret)
dev_err(dev->dev, "power gate command write failed.\n");
return ret;
@@ -611,18 +605,17 @@ EXPORT_SYMBOL_GPL(mei_hbm_pg);
*/
static int mei_hbm_stop_req(struct mei_device *dev)
{
- struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
- struct hbm_host_stop_request *req =
- (struct hbm_host_stop_request *)dev->wr_msg.data;
+ struct mei_msg_hdr mei_hdr;
+ struct hbm_host_stop_request req;
const size_t len = sizeof(struct hbm_host_stop_request);

- mei_hbm_hdr(mei_hdr, len);
+ mei_hbm_hdr(&mei_hdr, len);

- memset(req, 0, len);
- req->hbm_cmd = HOST_STOP_REQ_CMD;
- req->reason = DRIVER_STOP_REQUEST;
+ memset(&req, 0, len);
+ req.hbm_cmd = HOST_STOP_REQ_CMD;
+ req.reason = DRIVER_STOP_REQUEST;

- return mei_write_message(dev, mei_hdr, dev->wr_msg.data);
+ return mei_write_message(dev, &mei_hdr, &req);
}

/**
@@ -636,9 +629,10 @@ static int mei_hbm_stop_req(struct mei_device *dev)
int mei_hbm_cl_flow_control_req(struct mei_device *dev, struct mei_cl *cl)
{
const size_t len = sizeof(struct hbm_flow_control);
+ u8 buf[len];

cl_dbg(dev, cl, "sending flow control\n");
- return mei_hbm_cl_write(dev, cl, MEI_FLOW_CONTROL_CMD, len);
+ return mei_hbm_cl_write(dev, cl, MEI_FLOW_CONTROL_CMD, buf, len);
}

/**
@@ -714,8 +708,9 @@ static void mei_hbm_cl_flow_control_res(struct mei_device *dev,
int mei_hbm_cl_disconnect_req(struct mei_device *dev, struct mei_cl *cl)
{
const size_t len = sizeof(struct hbm_client_connect_request);
+ u8 buf[len];

- return mei_hbm_cl_write(dev, cl, CLIENT_DISCONNECT_REQ_CMD, len);
+ return mei_hbm_cl_write(dev, cl, CLIENT_DISCONNECT_REQ_CMD, buf, len);
}

/**
@@ -729,8 +724,9 @@ int mei_hbm_cl_disconnect_req(struct mei_device *dev, struct mei_cl *cl)
int mei_hbm_cl_disconnect_rsp(struct mei_device *dev, struct mei_cl *cl)
{
const size_t len = sizeof(struct hbm_client_connect_response);
+ u8 buf[len];

- return mei_hbm_cl_write(dev, cl, CLIENT_DISCONNECT_RES_CMD, len);
+ return mei_hbm_cl_write(dev, cl, CLIENT_DISCONNECT_RES_CMD, buf, len);
}

/**
@@ -765,8 +761,9 @@ static void mei_hbm_cl_disconnect_res(struct mei_device *dev, struct mei_cl *cl,
int mei_hbm_cl_connect_req(struct mei_device *dev, struct mei_cl *cl)
{
const size_t len = sizeof(struct hbm_client_connect_request);
+ u8 buf[len];

- return mei_hbm_cl_write(dev, cl, CLIENT_CONNECT_REQ_CMD, len);
+ return mei_hbm_cl_write(dev, cl, CLIENT_CONNECT_REQ_CMD, buf, len);
}

/**
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index c9e01021eadf..e5e32503d4bc 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -382,7 +382,6 @@ const char *mei_pg_state_str(enum mei_pg_state state);
*
* @hbuf_depth : depth of hardware host/write buffer is slots
* @hbuf_is_ready : query if the host host/write buffer is ready
- * @wr_msg : the buffer for hbm control messages
*
* @version : HBM protocol version in use
* @hbm_f_pg_supported : hbm feature pgi protocol
@@ -467,12 +466,6 @@ struct mei_device {
u8 hbuf_depth;
bool hbuf_is_ready;

- /* used for control messages */
- struct {
- struct mei_msg_hdr hdr;
- unsigned char data[128];
- } wr_msg;
-
struct hbm_version version;
unsigned int hbm_f_pg_supported:1;
unsigned int hbm_f_dc_supported:1;
@@ -670,8 +663,7 @@ static inline size_t mei_hbuf_max_len(const struct mei_device *dev)
}

static inline int mei_write_message(struct mei_device *dev,
- struct mei_msg_hdr *hdr,
- unsigned char *buf)
+ struct mei_msg_hdr *hdr, void *buf)
{
return dev->ops->write(dev, hdr, buf);
}
--
2.5.5

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