[PATCH v3] usb: udc: core: Use lock when write to soft_connect

[PATCH v3] usb: udc: core: Use lock when write to soft_connect

[Thinh Nguyen]

Use lock to guard against concurrent access for soft-connect/disconnect
operations when writing to soft_connect sysfs.

Cc: stable@vger.kernel.org
Fixes: 2ccea03a8f7e ("usb: gadget: introduce UDC Class")
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
---
 Changes in v3:
 - Improve flow: avoid assigning "ret = n" early
 Changes in v2:
 - Consolidate mutex_unlock to a single place using "goto out"

 drivers/usb/gadget/udc/core.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index 6a62bbd01324..ea114f922ccf 100644
--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -1529,10 +1529,13 @@ static ssize_t soft_connect_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t n)
 {
 	struct usb_udc		*udc = container_of(dev, struct usb_udc, dev);
+	ssize_t			ret;
 
+	mutex_lock(&udc_lock);
 	if (!udc->driver) {
 		dev_err(dev, "soft-connect without a gadget driver\n");
-		return -EOPNOTSUPP;
+		ret = -EOPNOTSUPP;
+		goto out;
 	}
 
 	if (sysfs_streq(buf, "connect")) {
@@ -1543,10 +1546,14 @@ static ssize_t soft_connect_store(struct device *dev,
 		usb_gadget_udc_stop(udc);
 	} else {
 		dev_err(dev, "unsupported command '%s'\n", buf);
-		return -EINVAL;
+		ret = -EINVAL;
+		goto out;
 	}
 
-	return n;
+	ret = n;
+out:
+	mutex_unlock(&udc_lock);
+	return ret;
 }
 static DEVICE_ATTR_WO(soft_connect);
 

base-commit: 4e0dcf62ab4cf917d0cbe751b8bf229a065248d4
-- 
2.28.0

Re: [PATCH v3] usb: udc: core: Use lock when write to soft_connect

[Felipe Balbi]

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Hi,

Thinh Nguyen <Thinh.Nguyen@synopsys.com> writes:
> Use lock to guard against concurrent access for soft-connect/disconnect
> operations when writing to soft_connect sysfs.
>
> Cc: stable@vger.kernel.org
> Fixes: 2ccea03a8f7e ("usb: gadget: introduce UDC Class")
> Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>

this does look better than v2 :-p

Acked-by: Felipe Balbi <balbi@kernel.org>

-- 
balbi

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