[PATCH v2 11/20] rpmsg: glink: Fix idr_lock from mutex to spinlock

Sricharan R
2017-08-24T07:22:41Z

The channel members lcids, rcids synchronised using
the idr_lock is accessed in both atomic/non-atomic
contexts. The readers are not currently synchronised.
That no correct, so add the readers as well under the
lock and use a spinlock.

Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
drivers/rpmsg/qcom_glink_native.c | 58 +++++++++++++++++++++++++++------------
1 file changed, 40 insertions(+), 18 deletions(-)

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index 777ac6b..588a56c 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -92,7 +92,7 @@ struct qcom_glink {

struct mutex tx_lock;

- struct mutex idr_lock;
+ spinlock_t idr_lock;
struct idr lcids;
struct idr rcids;
unsigned long features;
@@ -309,14 +309,15 @@ static int qcom_glink_send_open_req(struct qcom_glink *glink,
int name_len = strlen(channel->name) + 1;
int req_len = ALIGN(sizeof(req.msg) + name_len, 8);
int ret;
+ unsigned long flags;

kref_get(&channel->refcount);

- mutex_lock(&glink->idr_lock);
+ spin_lock_irqsave(&glink->idr_lock, flags);
ret = idr_alloc_cyclic(&glink->lcids, channel,
RPM_GLINK_CID_MIN, RPM_GLINK_CID_MAX,
GFP_KERNEL);
- mutex_unlock(&glink->idr_lock);
+ spin_unlock_irqrestore(&glink->idr_lock, flags);
if (ret < 0)
return ret;

@@ -334,10 +335,10 @@ static int qcom_glink_send_open_req(struct qcom_glink *glink,
return 0;

remove_idr:
- mutex_lock(&glink->idr_lock);
+ spin_lock_irqsave(&glink->idr_lock, flags);
idr_remove(&glink->lcids, channel->lcid);
channel->lcid = 0;
- mutex_unlock(&glink->idr_lock);
+ spin_unlock_irqrestore(&glink->idr_lock, flags);

return ret;
}
@@ -463,6 +464,7 @@ static int qcom_glink_rx_data(struct qcom_glink *glink, size_t avail)
unsigned int chunk_size;
unsigned int left_size;
unsigned int rcid;
+ unsigned long flags;

if (avail < sizeof(hdr)) {
dev_dbg(glink->dev, "Not enough data in fifo\n");
@@ -482,7 +484,9 @@ static int qcom_glink_rx_data(struct qcom_glink *glink, size_t avail)
return -EINVAL;

rcid = le16_to_cpu(hdr.msg.param1);
+ spin_lock_irqsave(&glink->idr_lock, flags);
channel = idr_find(&glink->rcids, rcid);
+ spin_unlock_irqrestore(&glink->idr_lock, flags);
if (!channel) {
dev_dbg(glink->dev, "Data on non-existing channel\n");

@@ -543,11 +547,13 @@ static int qcom_glink_rx_open_ack(struct qcom_glink *glink, unsigned int lcid)
{
struct glink_channel *channel;

+ spin_lock(&glink->idr_lock);
channel = idr_find(&glink->lcids, lcid);
if (!channel) {
dev_err(glink->dev, "Invalid open ack packet\n");
return -EINVAL;
}
+ spin_unlock(&glink->idr_lock);

complete(&channel->open_ack);

@@ -621,6 +627,7 @@ static struct glink_channel *qcom_glink_create_local(struct qcom_glink *glink,
{
struct glink_channel *channel;
int ret;
+ unsigned long flags;

channel = qcom_glink_alloc_channel(glink, name);
if (IS_ERR(channel))
@@ -644,9 +651,9 @@ static struct glink_channel *qcom_glink_create_local(struct qcom_glink *glink,

err_timeout:
/* qcom_glink_send_open_req() did register the channel in lcids*/
- mutex_lock(&glink->idr_lock);
+ spin_lock_irqsave(&glink->idr_lock, flags);
idr_remove(&glink->lcids, channel->lcid);
- mutex_unlock(&glink->idr_lock);
+ spin_unlock_irqrestore(&glink->idr_lock, flags);

release_channel:
/* Release qcom_glink_send_open_req() reference */
@@ -703,11 +710,14 @@ static struct rpmsg_endpoint *qcom_glink_create_ept(struct rpmsg_device *rpdev,
const char *name = chinfo.name;
int cid;
int ret;
+ unsigned long flags;

+ spin_lock_irqsave(&glink->idr_lock, flags);
idr_for_each_entry(&glink->rcids, channel, cid) {
if (!strcmp(channel->name, name))
break;
}
+ spin_unlock_irqrestore(&glink->idr_lock, flags);

if (!channel) {
channel = qcom_glink_create_local(glink, name);
@@ -829,11 +839,14 @@ static int qcom_glink_rx_open(struct qcom_glink *glink, unsigned int rcid,
struct device_node *node;
int lcid;
int ret;
+ unsigned long flags;

+ spin_lock_irqsave(&glink->idr_lock, flags);
idr_for_each_entry(&glink->lcids, channel, lcid) {
if (!strcmp(channel->name, name))
break;
}
+ spin_unlock_irqrestore(&glink->idr_lock, flags);

if (!channel) {
channel = qcom_glink_alloc_channel(glink, name);
@@ -844,15 +857,15 @@ static int qcom_glink_rx_open(struct qcom_glink *glink, unsigned int rcid,
create_device = true;
}

- mutex_lock(&glink->idr_lock);
+ spin_lock_irqsave(&glink->idr_lock, flags);
ret = idr_alloc(&glink->rcids, channel, rcid, rcid + 1, GFP_KERNEL);
if (ret < 0) {
dev_err(glink->dev, "Unable to insert channel into rcid list\n");
- mutex_unlock(&glink->idr_lock);
+ spin_unlock_irqrestore(&glink->idr_lock, flags);
goto free_channel;
}
channel->rcid = ret;
- mutex_unlock(&glink->idr_lock);
+ spin_unlock_irqrestore(&glink->idr_lock, flags);

complete(&channel->open_req);

@@ -886,10 +899,10 @@ static int qcom_glink_rx_open(struct qcom_glink *glink, unsigned int rcid,
free_rpdev:
kfree(rpdev);
rcid_remove:
- mutex_lock(&glink->idr_lock);
+ spin_lock_irqsave(&glink->idr_lock, flags);
idr_remove(&glink->rcids, channel->rcid);
channel->rcid = 0;
- mutex_unlock(&glink->idr_lock);
+ spin_unlock_irqrestore(&glink->idr_lock, flags);
free_channel:
/* Release the reference, iff we took it */
if (create_device)
@@ -902,8 +915,11 @@ static void qcom_glink_rx_close(struct qcom_glink *glink, unsigned int rcid)
{
struct rpmsg_channel_info chinfo;
struct glink_channel *channel;
+ unsigned long flags;

+ spin_lock_irqsave(&glink->idr_lock, flags);
channel = idr_find(&glink->rcids, rcid);
+ spin_unlock_irqrestore(&glink->idr_lock, flags);
if (WARN(!channel, "close request on unknown channel\n"))
return;

@@ -917,10 +933,10 @@ static void qcom_glink_rx_close(struct qcom_glink *glink, unsigned int rcid)

qcom_glink_send_close_ack(glink, channel->rcid);

- mutex_lock(&glink->idr_lock);
+ spin_lock_irqsave(&glink->idr_lock, flags);
idr_remove(&glink->rcids, channel->rcid);
channel->rcid = 0;
- mutex_unlock(&glink->idr_lock);
+ spin_unlock_irqrestore(&glink->idr_lock, flags);

kref_put(&channel->refcount, qcom_glink_channel_release);
}
@@ -928,15 +944,18 @@ static void qcom_glink_rx_close(struct qcom_glink *glink, unsigned int rcid)
static void qcom_glink_rx_close_ack(struct qcom_glink *glink, unsigned int lcid)
{
struct glink_channel *channel;
+ unsigned long flags;

+ spin_lock_irqsave(&glink->idr_lock, flags);
channel = idr_find(&glink->lcids, lcid);
- if (WARN(!channel, "close ack on unknown channel\n"))
+ if (WARN(!channel, "close ack on unknown channel\n")) {
+ spin_unlock_irqrestore(&glink->idr_lock, flags);
return;
+ }

- mutex_lock(&glink->idr_lock);
idr_remove(&glink->lcids, channel->lcid);
channel->lcid = 0;
- mutex_unlock(&glink->idr_lock);
+ spin_unlock_irqrestore(&glink->idr_lock, flags);

kref_put(&channel->refcount, qcom_glink_channel_release);
}
@@ -1017,7 +1036,7 @@ struct qcom_glink *qcom_glink_native_probe(struct device *dev,
INIT_LIST_HEAD(&glink->rx_queue);
INIT_WORK(&glink->rx_work, qcom_glink_work);

- mutex_init(&glink->idr_lock);
+ spin_lock_init(&glink->idr_lock);
idr_init(&glink->lcids);
idr_init(&glink->rcids);

@@ -1060,6 +1079,7 @@ void qcom_glink_native_remove(struct qcom_glink *glink)
struct glink_channel *channel;
int cid;
int ret;
+ unsigned long flags;

disable_irq(glink->irq);
cancel_work_sync(&glink->rx_work);
@@ -1068,12 +1088,14 @@ void qcom_glink_native_remove(struct qcom_glink *glink)
if (ret)
dev_warn(glink->dev, "Can't remove GLINK devices: %d\n", ret);

+ spin_lock_irqsave(&glink->idr_lock, flags);
/* Release any defunct local channels, waiting for close-ack */
idr_for_each_entry(&glink->lcids, channel, cid)
kref_put(&channel->refcount, qcom_glink_channel_release);

idr_destroy(&glink->lcids);
idr_destroy(&glink->rcids);
+ spin_unlock_irqrestore(&glink->idr_lock, flags);
mbox_free_channel(glink->mbox_chan);
}