ppdev: fix registering same device name (9a69645d) · Commits · 戴 / test

Usually every parallel port will have a single pardev registered with it. But ppdev driver is an exception. This userspace parallel port driver allows to create multiple parrallel port devices for a single parallel port. And as a result we were having a big warning like: "sysfs: cannot create duplicate filename '/devices/parport0/ppdev0.0'". And with that many parallel port printers stopped working. We have been using the minor number as the id field while registering a parralel port device with a parralel port. But when there are multiple parrallel port device for one single parallel port, they all tried to register with the same name like 'pardev0.0' and everything started failing. Use an incremented index as the id instead of the minor number. Fixes: ("ppdev: use new parport device model") Cc: stable <stable@vger.kernel.org> # v4.9+ Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1414656 Bugzilla: https://bugs.archlinux.org/task/52322 Tested-by:

James Feeney <james@nurealm.net> Signed-off-by:

Sudip Mukherjee <sudip.mukherjee@codethink.co.uk> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/char/ppdev.c

+9 −2

Original line number	Diff line number	Diff line
		@@ -84,11 +84,14 @@ struct pp_struct {
		struct ieee1284_info state;
		struct ieee1284_info saved_state;
		long default_inactivity;
		int index;
		};

		/* should we use PARDEVICE_MAX here? */
		static struct device *devices[PARPORT_MAX];

		static DEFINE_IDA(ida_index);

		/* pp_struct.flags bitfields */
		#define PP_CLAIMED (1<<0)
		#define PP_EXCL (1<<1)
		@@ -290,7 +293,7 @@ static int register_device(int minor, struct pp_struct *pp)
		struct pardevice *pdev = NULL;
		char *name;
		struct pardev_cb ppdev_cb;
		int rc = 0;
		int rc = 0, index;

		name = kasprintf(GFP_KERNEL, CHRDEV "%x", minor);
		if (name == NULL)
		@@ -303,20 +306,23 @@ static int register_device(int minor, struct pp_struct *pp)
		goto err;
		}

		index = ida_simple_get(&ida_index, 0, 0, GFP_KERNEL);
		memset(&ppdev_cb, 0, sizeof(ppdev_cb));
		ppdev_cb.irq_func = pp_irq;
		ppdev_cb.flags = (pp->flags & PP_EXCL) ? PARPORT_FLAG_EXCL : 0;
		ppdev_cb.private = pp;
		pdev = parport_register_dev_model(port, name, &ppdev_cb, minor);
		pdev = parport_register_dev_model(port, name, &ppdev_cb, index);
		parport_put_port(port);

		if (!pdev) {
		pr_warn("%s: failed to register device!\n", name);
		rc = -ENXIO;
		ida_simple_remove(&ida_index, index);
		goto err;
		}

		pp->pdev = pdev;
		pp->index = index;
		dev_dbg(&pdev->dev, "registered pardevice\n");
		err:
		kfree(name);
		@@ -755,6 +761,7 @@ static int pp_release(struct inode inode, struct file file)

		if (pp->pdev) {
		parport_unregister_device(pp->pdev);
		ida_simple_remove(&ida_index, pp->index);
		pp->pdev = NULL;
		pr_debug(CHRDEV "%x: unregistered pardevice\n", minor);
		}

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