[PATCH linux dev-4.10 v4 28/31] drivers: fsi: occ: Add cancel to remove() and fix probe()
Brad Bishop
bradleyb at fuzziesquirrel.com
Mon Oct 9 12:05:49 AEDT 2017
> On Oct 5, 2017, at 10:05 PM, Eddie James <eajames at linux.vnet.ibm.com> wrote:
>
> 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 | 71 +++++++++++++++++++++++++++++++++++++++----------------
> 1 file changed, 50 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/fsi/occ.c b/drivers/fsi/occ.c
> index bd0ad98..ec42fc0 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;
Can we have ENODEV here? That seems to be typical for this scenario and
ECANCELED seems to be for canceled AIO operations.
> +
> spin_lock_irq(&occ->list_lock);
>
> empty = list_empty(&occ->xfrs);
> @@ -132,6 +136,8 @@ 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)
> @@ -166,10 +172,10 @@ static int occ_open(struct inode *inode, struct file *file)
> return 0;
> }
>
> -static inline bool occ_read_ready(struct occ_xfr *xfr)
> +static inline bool occ_read_ready(struct occ_xfr *xfr, struct occ *occ)
> {
> return test_bit(XFR_COMPLETE, &xfr->flags) ||
> - test_bit(XFR_CANCELED, &xfr->flags);
> + test_bit(XFR_CANCELED, &xfr->flags) || occ->cancel;
> }
>
> static ssize_t occ_read_common(struct occ_client *client, char __user *ubuf,
> @@ -178,6 +184,7 @@ static ssize_t occ_read_common(struct occ_client *client, char __user *ubuf,
> int rc;
> size_t bytes;
> struct occ_xfr *xfr;
> + struct occ *occ;
>
> if (!client)
> return -ENODEV;
> @@ -186,6 +193,7 @@ static ssize_t occ_read_common(struct occ_client *client, char __user *ubuf,
> return -EINVAL;
>
> xfr = &client->xfr;
> + occ = client->occ;
>
> spin_lock_irq(&client->lock);
>
> @@ -212,7 +220,7 @@ static ssize_t occ_read_common(struct occ_client *client, char __user *ubuf,
> spin_unlock_irq(&client->lock);
>
> rc = wait_event_interruptible(client->wait,
> - occ_read_ready(xfr));
> + occ_read_ready(xfr, occ));
>
> spin_lock_irq(&client->lock);
>
> @@ -285,7 +293,7 @@ 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;
> }
> @@ -323,8 +331,11 @@ 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:
> @@ -602,6 +613,9 @@ 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);
> @@ -762,23 +776,13 @@ 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;
> @@ -788,20 +792,45 @@ 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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