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Subject[PATCH 4.4 12/38] usb: udc: core: Use lock when write to soft_connect
Date
From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>

commit c28095bc99073ddda65e4f31f6ae0d908d4d5cd8 upstream

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

Fixes: 2ccea03a8f7e ("usb: gadget: introduce UDC Class")
Cc: stable@vger.kernel.org
Acked-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/338ea01fbd69b1985ef58f0f59af02c805ddf189.1610611437.git.Thinh.Nguyen@synopsys.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[sudip: manual backporting to old file]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/gadget/udc/udc-core.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)

--- a/drivers/usb/gadget/udc/udc-core.c
+++ b/drivers/usb/gadget/udc/udc-core.c
@@ -612,10 +612,13 @@ static ssize_t usb_udc_softconn_store(st
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")) {
@@ -627,10 +630,14 @@ static ssize_t usb_udc_softconn_store(st
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(soft_connect, S_IWUSR, NULL, usb_udc_softconn_store);


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