[PATCH linux dev-4.10 v3 28/31] drivers: fsi: occ: Add cancel to remove() and fix probe()
Eddie James
eajames at linux.vnet.ibm.com
Fri Oct 6 06:24:21 AEDT 2017
From: "Edward A. James" <eajames at us.ibm.com>
Need some data to indicate to clients and the rest of the driver when
the device is being removed, so add a cancel boolean. Fix up both the
probe and remove functions to properly handle failures and prevent
deadlocks.
Signed-off-by: Edward A. James <eajames at us.ibm.com>
---
drivers/fsi/occ.c | 86 +++++++++++++++++++++++++++++++++++++++----------------
1 file changed, 62 insertions(+), 24 deletions(-)
diff --git a/drivers/fsi/occ.c b/drivers/fsi/occ.c
index 8555e99..1770823 100644
--- a/drivers/fsi/occ.c
+++ b/drivers/fsi/occ.c
@@ -46,6 +46,7 @@ struct occ {
spinlock_t list_lock; /* lock access to the xfrs list */
struct mutex occ_lock; /* lock access to the hardware */
struct work_struct work;
+ bool cancel;
};
#define to_occ(x) container_of((x), struct occ, mdev)
@@ -117,12 +118,15 @@ struct occ_client {
static DEFINE_IDA(occ_ida);
-static void occ_enqueue_xfr(struct occ_xfr *xfr)
+static int occ_enqueue_xfr(struct occ_xfr *xfr)
{
int empty;
struct occ_client *client = to_client(xfr);
struct occ *occ = client->occ;
+ if (occ->cancel)
+ return -ECANCELED;
+
spin_lock_irq(&occ->list_lock);
empty = list_empty(&occ->xfrs);
@@ -132,14 +136,20 @@ static void occ_enqueue_xfr(struct occ_xfr *xfr)
if (empty)
queue_work(occ_wq, &occ->work);
+
+ return 0;
}
static struct occ_client *occ_open_common(struct occ *occ, unsigned long flags)
{
- struct occ_client *client = kzalloc(sizeof(*client), GFP_KERNEL);
+ struct occ_client *client;
+
+ if (occ->cancel)
+ return ERR_PTR(-ECANCELED);
+ client = kzalloc(sizeof(*client), GFP_KERNEL);
if (!client)
- return NULL;
+ return ERR_PTR(-ENOMEM);
client->occ = occ;
spin_lock_init(&client->lock);
@@ -158,8 +168,8 @@ static int occ_open(struct inode *inode, struct file *file)
struct occ *occ = to_occ(mdev);
client = occ_open_common(occ, file->f_flags);
- if (!client)
- return -ENOMEM;
+ if (IS_ERR(client))
+ return PTR_ERR(client);
file->private_data = client;
@@ -172,6 +182,7 @@ static ssize_t occ_read_common(struct occ_client *client, char __user *ubuf,
int rc;
size_t bytes;
struct occ_xfr *xfr = &client->xfr;
+ struct occ *occ = client->occ;
if (len > OCC_SRAM_BYTES)
return -EINVAL;
@@ -204,7 +215,8 @@ static ssize_t occ_read_common(struct occ_client *client, char __user *ubuf,
test_bit(XFR_COMPLETE,
&xfr->flags) ||
test_bit(XFR_CANCELED,
- &xfr->flags));
+ &xfr->flags) ||
+ occ->cancel);
spin_lock_irq(&client->lock);
@@ -272,7 +284,7 @@ static ssize_t occ_write_common(struct occ_client *client,
spin_lock_irq(&client->lock);
- if (test_and_set_bit(CLIENT_XFR_PENDING, &client->flags)) {
+ if (test_bit(CLIENT_XFR_PENDING, &client->flags)) {
rc = -EBUSY;
goto done;
}
@@ -310,8 +322,11 @@ static ssize_t occ_write_common(struct occ_client *client,
xfr->cmd_data_length = data_length + 6;
client->read_offset = 0;
- occ_enqueue_xfr(xfr);
+ rc = occ_enqueue_xfr(xfr);
+ if (rc)
+ goto done;
+ set_bit(CLIENT_XFR_PENDING, &client->flags);
rc = len;
done:
@@ -583,6 +598,9 @@ static void occ_worker(struct work_struct *work)
struct device *sbefifo = occ->sbefifo;
again:
+ if (occ->cancel)
+ return;
+
spin_lock_irq(&occ->list_lock);
xfr = list_first_entry_or_null(&occ->xfrs, struct occ_xfr, link);
@@ -676,12 +694,17 @@ static void occ_worker(struct work_struct *work)
struct occ_client *occ_drv_open(struct device *dev, unsigned long flags)
{
+ struct occ_client *client;
struct occ *occ = dev_get_drvdata(dev);
if (!occ)
return NULL;
- return occ_open_common(occ, flags);
+ client = occ_open_common(occ, flags);
+ if (IS_ERR(client))
+ return NULL;
+
+ return client;
}
EXPORT_SYMBOL_GPL(occ_drv_open);
@@ -752,23 +775,13 @@ static int occ_probe(struct platform_device *pdev)
if (occ->idx < 0)
occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX,
GFP_KERNEL);
- } else
+ } else {
occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX,
GFP_KERNEL);
-
- /* create platform devs for dts child nodes (hwmon, etc) */
- for_each_child_of_node(dev->of_node, np) {
- snprintf(child_name, sizeof(child_name), "occ%d-dev%d",
- occ->idx, child_idx++);
- child = of_platform_device_create(np, child_name, dev);
- if (!child)
- dev_warn(dev,
- "failed to create child node dev\n");
}
- } else
+ } else {
occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX, GFP_KERNEL);
-
- platform_set_drvdata(pdev, occ);
+ }
snprintf(occ->name, sizeof(occ->name), "occ%d", occ->idx);
occ->mdev.fops = &occ_fops;
@@ -778,20 +791,45 @@ static int occ_probe(struct platform_device *pdev)
rc = misc_register(&occ->mdev);
if (rc) {
- dev_err(dev, "failed to register miscdevice\n");
+ dev_err(dev, "failed to register miscdevice: %d\n", rc);
+ ida_simple_remove(&occ_ida, occ->idx);
return rc;
}
+ /* create platform devs for dts child nodes (hwmon, etc) */
+ for_each_available_child_of_node(dev->of_node, np) {
+ snprintf(child_name, sizeof(child_name), "occ%d-dev%d",
+ occ->idx, child_idx++);
+ child = of_platform_device_create(np, child_name, dev);
+ if (!child)
+ dev_warn(dev, "failed to create child node dev\n");
+ }
+
+ platform_set_drvdata(pdev, occ);
+
return 0;
}
static int occ_remove(struct platform_device *pdev)
{
struct occ *occ = platform_get_drvdata(pdev);
+ struct occ_xfr *xfr;
+ struct occ_client *client;
+
+ occ->cancel = true;
+
+ spin_lock_irq(&occ->list_lock);
+ list_for_each_entry(xfr, &occ->xfrs, link) {
+ client = to_client(xfr);
+ wake_up_all(&client->wait);
+ }
+ spin_unlock_irq(&occ->list_lock);
- flush_work(&occ->work);
misc_deregister(&occ->mdev);
device_for_each_child(&pdev->dev, NULL, occ_unregister_child);
+
+ cancel_work_sync(&occ->work);
+
ida_simple_remove(&occ_ida, occ->idx);
return 0;
--
1.8.3.1
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