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Subject[PATCH 4.9 001/152] ppdev: check before attaching port
Date
4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sudip Mukherjee <sudipm.mukherjee@gmail.com>

commit dd5c472a60e43549d789a17a8444513eec64bd7e upstream.

After parport starts using the device model, all pardevice drivers
should decide in their match_port callback function if they want to
attach with that particulatr port. ppdev has been converted to use the
new parport device-model code but pp_attach() tried to attach with all
the ports.
Create a new array of pointer and use that to remember the ports we
have attached. And use that information to skip attaching ports which
we have already attached.

Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/char/ppdev.c | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)

--- a/drivers/char/ppdev.c
+++ b/drivers/char/ppdev.c
@@ -86,6 +86,9 @@ struct pp_struct {
long default_inactivity;
};

+/* should we use PARDEVICE_MAX here? */
+static struct device *devices[PARPORT_MAX];
+
/* pp_struct.flags bitfields */
#define PP_CLAIMED (1<<0)
#define PP_EXCL (1<<1)
@@ -789,13 +792,29 @@ static const struct file_operations pp_f

static void pp_attach(struct parport *port)
{
- device_create(ppdev_class, port->dev, MKDEV(PP_MAJOR, port->number),
- NULL, "parport%d", port->number);
+ struct device *ret;
+
+ if (devices[port->number])
+ return;
+
+ ret = device_create(ppdev_class, port->dev,
+ MKDEV(PP_MAJOR, port->number), NULL,
+ "parport%d", port->number);
+ if (IS_ERR(ret)) {
+ pr_err("Failed to create device parport%d\n",
+ port->number);
+ return;
+ }
+ devices[port->number] = ret;
}

static void pp_detach(struct parport *port)
{
+ if (!devices[port->number])
+ return;
+
device_destroy(ppdev_class, MKDEV(PP_MAJOR, port->number));
+ devices[port->number] = NULL;
}

static int pp_probe(struct pardevice *par_dev)

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