This patch introduces the below two helpers to prepare for solving
the usbnet runtime PM problem, which may cause some network utilities
(ifconfig, ethtool,...) touch a suspended device.
usbnet_read_cmd_nopm()
usbnet_write_cmd_nopm()
The above two helpers should be called by usbnet resume/suspend
callback to avoid deadlock.
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxxxxx>
---
drivers/net/usb/usbnet.c | 62 ++++++++++++++++++++++++++++++++++++++++----
include/linux/usb/usbnet.h | 4 +++
2 files changed, 61 insertions(+), 5 deletions(-)
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 09ea47a..a7fb074 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1614,8 +1614,8 @@ void usbnet_device_suggests_idle(struct usbnet *dev)
EXPORT_SYMBOL(usbnet_device_suggests_idle);
/*-------------------------------------------------------------------------*/
-int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
- u16 value, u16 index, void *data, u16 size)
+static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
+ u16 value, u16 index, void *data, u16 size)
{
void *buf = NULL;
int err = -ENOMEM;
@@ -1639,10 +1639,10 @@ int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
out:
return err;
}
-EXPORT_SYMBOL_GPL(usbnet_read_cmd);
-int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
- u16 value, u16 index, const void *data, u16 size)
+static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
+ u16 value, u16 index, const void *data,
+ u16 size)
{
void *buf = NULL;
int err = -ENOMEM;
@@ -1665,8 +1665,56 @@ int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
out:
return err;
}
+
+/*
+ * The function can't be called inside suspend/resume callback,
+ * otherwise deadlock will be caused.
+ */
+int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
+ u16 value, u16 index, void *data, u16 size)
+{
+ return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
+ data, size);
+}
+EXPORT_SYMBOL_GPL(usbnet_read_cmd);
+
+/*
+ * The function can't be called inside suspend/resume callback,
+ * otherwise deadlock will be caused.
+ */
+int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
+ u16 value, u16 index, const void *data, u16 size)
+{
+ return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
+ data, size);
+}
EXPORT_SYMBOL_GPL(usbnet_write_cmd);
+/*
+ * The function can be called inside suspend/resume callback safely
+ * and should only be called by suspend/resume callback generally.
+ */
+int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
+ u16 value, u16 index, void *data, u16 size)
+{
+ return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
+ data, size);
+}
+EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
+
+/*
+ * The function can be called inside suspend/resume callback safely
+ * and should only be called by suspend/resume callback generally.
+ */
+int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
+ u16 value, u16 index, const void *data,
+ u16 size)
+{
+ return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
+ data, size);
+}
+EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
+
static void usbnet_async_cmd_cb(struct urb *urb)
{
struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
@@ -1680,6 +1728,10 @@ static void usbnet_async_cmd_cb(struct urb *urb)
usb_free_urb(urb);
}
+/*
+ * The caller must make sure that device can't be put into suspend
+ * state until the control URB completes.
+ */
int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
u16 value, u16 index, const void *data, u16 size)
{
diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h
index 4410e416..9bbeabf 100644
--- a/include/linux/usb/usbnet.h
+++ b/include/linux/usb/usbnet.h
@@ -167,6 +167,10 @@ extern int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
u16 value, u16 index, void *data, u16 size);
extern int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
u16 value, u16 index, const void *data, u16 size);
+extern int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
+ u16 value, u16 index, void *data, u16 size);
+extern int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
+ u16 value, u16 index, const void *data, u16 size);
extern int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
u16 value, u16 index, const void *data, u16 size);
--
1.7.9.5
--
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