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clear-pkgs-linux-iot-lts2018/0144-mei-add-a-spin-lock-to...

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Alexander Usyskin <alexander.usyskin@intel.com>
Date: Sun, 12 Aug 2018 14:21:27 +0300
Subject: [PATCH] mei: add a spin lock to protect rd_completed queue
This will add ability to access read completed queue
outside of the driver big lock.
Change-Id: I5713f32bca80b4b6ac3bf7cb9b21726b3ce7a224
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
drivers/misc/mei/bus.c | 6 +++---
drivers/misc/mei/client.c | 19 +++++++++++++------
drivers/misc/mei/client.h | 20 ++++++++++++++++++--
drivers/misc/mei/main.c | 6 +++---
drivers/misc/mei/mei_dev.h | 2 ++
5 files changed, 39 insertions(+), 14 deletions(-)
diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index b8496942c533..26bf76108950 100644
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -161,7 +161,7 @@ ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length,
if (timeout) {
rets = wait_event_interruptible_timeout
(cl->rx_wait,
- (!list_empty(&cl->rd_completed)) ||
+ mei_cl_read_cb(cl, NULL) ||
(!mei_cl_is_connected(cl)),
msecs_to_jiffies(timeout));
if (rets == 0)
@@ -174,7 +174,7 @@ ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length,
} else {
if (wait_event_interruptible
(cl->rx_wait,
- (!list_empty(&cl->rd_completed)) ||
+ mei_cl_read_cb(cl, NULL) ||
(!mei_cl_is_connected(cl)))) {
if (signal_pending(current))
return -EINTR;
@@ -207,7 +207,7 @@ ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length,
rets = r_length;
free:
- mei_io_cb_free(cb);
+ mei_cl_del_rd_completed(cl, cb);
out:
mutex_unlock(&bus->device_lock);
diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index 6dbe8d856fb8..989fc73d241c 100644
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -513,15 +513,19 @@ struct mei_cl_cb *mei_cl_enqueue_ctrl_wr_cb(struct mei_cl *cl, size_t length,
*
* Return: cb on success, NULL if cb is not found
*/
-struct mei_cl_cb *mei_cl_read_cb(const struct mei_cl *cl, const struct file *fp)
+struct mei_cl_cb *mei_cl_read_cb(struct mei_cl *cl, const struct file *fp)
{
struct mei_cl_cb *cb;
+ struct mei_cl_cb *ret_cb = NULL;
+ spin_lock(&cl->rd_completed_lock);
list_for_each_entry(cb, &cl->rd_completed, list)
- if (!fp || fp == cb->fp)
- return cb;
-
- return NULL;
+ if (!fp || fp == cb->fp) {
+ ret_cb = cb;
+ break;
+ }
+ spin_unlock(&cl->rd_completed_lock);
+ return ret_cb;
}
/**
@@ -547,7 +551,9 @@ int mei_cl_flush_queues(struct mei_cl *cl, const struct file *fp)
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);
+ spin_lock(&cl->rd_completed_lock);
mei_io_list_free_fp(&cl->rd_completed, fp);
+ spin_unlock(&cl->rd_completed_lock);
return 0;
}
@@ -565,6 +571,7 @@ 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);
+ spin_lock_init(&cl->rd_completed_lock);
INIT_LIST_HEAD(&cl->rd_completed);
INIT_LIST_HEAD(&cl->rd_pending);
INIT_LIST_HEAD(&cl->link);
@@ -1843,7 +1850,7 @@ void mei_cl_complete(struct mei_cl *cl, struct mei_cl_cb *cb)
break;
case MEI_FOP_READ:
- list_add_tail(&cb->list, &cl->rd_completed);
+ mei_cl_add_rd_completed(cl, cb);
if (!mei_cl_is_fixed_address(cl) &&
!WARN_ON(!cl->rx_flow_ctrl_creds))
cl->rx_flow_ctrl_creds--;
diff --git a/drivers/misc/mei/client.h b/drivers/misc/mei/client.h
index 0d23efcc74ff..bb74eea3dba5 100644
--- a/drivers/misc/mei/client.h
+++ b/drivers/misc/mei/client.h
@@ -95,8 +95,24 @@ int mei_cl_unlink(struct mei_cl *cl);
struct mei_cl *mei_cl_alloc_linked(struct mei_device *dev);
-struct mei_cl_cb *mei_cl_read_cb(const struct mei_cl *cl,
- const struct file *fp);
+struct mei_cl_cb *mei_cl_read_cb(struct mei_cl *cl, const struct file *fp);
+
+static inline void mei_cl_add_rd_completed(struct mei_cl *cl,
+ struct mei_cl_cb *cb)
+{
+ spin_lock(&cl->rd_completed_lock);
+ list_add_tail(&cb->list, &cl->rd_completed);
+ spin_unlock(&cl->rd_completed_lock);
+}
+
+static inline void mei_cl_del_rd_completed(struct mei_cl *cl,
+ struct mei_cl_cb *cb)
+{
+ spin_lock(&cl->rd_completed_lock);
+ mei_io_cb_free(cb);
+ spin_unlock(&cl->rd_completed_lock);
+}
+
struct mei_cl_cb *mei_cl_alloc_cb(struct mei_cl *cl, size_t length,
enum mei_cb_file_ops type,
const struct file *fp);
diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index 87281b3695e6..6227b401ce3e 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -181,7 +181,7 @@ static ssize_t mei_read(struct file *file, char __user *ubuf,
mutex_unlock(&dev->device_lock);
if (wait_event_interruptible(cl->rx_wait,
- !list_empty(&cl->rd_completed) ||
+ mei_cl_read_cb(cl, file) ||
!mei_cl_is_connected(cl))) {
if (signal_pending(current))
return -EINTR;
@@ -232,7 +232,7 @@ static ssize_t mei_read(struct file *file, char __user *ubuf,
goto out;
free:
- mei_io_cb_free(cb);
+ mei_cl_del_rd_completed(cl, cb);
*offset = 0;
out:
@@ -593,7 +593,7 @@ static __poll_t mei_poll(struct file *file, poll_table *wait)
if (req_events & (EPOLLIN | EPOLLRDNORM)) {
poll_wait(file, &cl->rx_wait, wait);
- if (!list_empty(&cl->rd_completed))
+ if (mei_cl_read_cb(cl, file))
mask |= EPOLLIN | EPOLLRDNORM;
else
mei_cl_read_start(cl, mei_cl_mtu(cl), file);
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index 6888fe763376..0467d0529667 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -227,6 +227,7 @@ struct mei_cl_cb {
* @tx_cb_queued: number of tx callbacks in queue
* @writing_state: state of the tx
* @rd_pending: pending read credits
+ * @rd_completed_lock: protects rd_completed queue
* @rd_completed: completed read
*
* @cldev: device on the mei client bus
@@ -252,6 +253,7 @@ struct mei_cl {
u8 tx_cb_queued;
enum mei_file_transaction_states writing_state;
struct list_head rd_pending;
+ spinlock_t rd_completed_lock; /* protects rd_completed queue */
struct list_head rd_completed;
struct mei_cl_device *cldev;
--
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