From 77c090b85d2dc085dce3712d4a5faf8452531d58 Mon Sep 17 00:00:00 2001
From: Marcin Chrzanowski <marcin.j.chrzanowski@gmail.com>
Date: Thu, 3 May 2018 20:06:14 +0200
Subject: Store and use minor number

---
 char.c | 14 +++++++++++---
 char.h |  6 ++++--
 pci.c  |  4 ++--
 pci.h  |  4 ++++
 4 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/char.c b/char.c
index 7fe7652..b13b08a 100644
--- a/char.c
+++ b/char.c
@@ -5,6 +5,7 @@
 #include "linux/fs.h"
 
 #include "util.h"
+#include "pci.h"
 
 #define DOOMDEV_COUNT 256
 #define DOOMDEV_NAME "doom"
@@ -32,13 +33,14 @@ struct file_operations doomdev_fops = {
 	
 struct class *doom_class;
 
-int new_doomdev(void)
+int new_doomdev(struct pci_dev *dev)
 {
 	int err = 0;
 	int minor;
 	dev_t devt;
 	struct cdev *doom_cdev;
 	struct device *doomdev;
+	struct doom_data *doom_data;
 	if (next_minor >= DOOMDEV_COUNT) {
 		return -ENOMEM;
 	}
@@ -51,6 +53,9 @@ int new_doomdev(void)
 	doom_cdev->ops = &doomdev_fops;
 	ORFAIL(cdev_add(doom_cdev, first, 1), error_add);
 	minor = next_minor++;
+	doom_data = kmalloc(sizeof(*doom_data), GFP_KERNEL);
+	doom_data->minor = minor;
+	pci_set_drvdata(dev, doom_data);
 	devt = MKDEV(major, minor);
 	ORFAIL_PTR(device_create(doom_class, NULL, devt, NULL,
 				"doom%d", minor),
@@ -62,9 +67,12 @@ error_add:
 	return err;
 }
 
-void destroy_doomdev(void)
+void destroy_doomdev(struct pci_dev *dev)
 {
-	device_destroy(doom_class, first);
+	struct doom_data *data;
+	data = pci_get_drvdata(dev);
+	device_destroy(doom_class, MKDEV(major, data->minor));
+	kfree(data);
 }
 
 int char_init(void)
diff --git a/char.h b/char.h
index 503ba04..31e82a2 100644
--- a/char.h
+++ b/char.h
@@ -1,8 +1,10 @@
 #ifndef CHAR_H
 #define CHAR_H
 
-int new_doomdev(void);
-void destroy_doomdev(void);
+#include <linux/pci.h>
+
+int new_doomdev(struct pci_dev *dev);
+void destroy_doomdev(struct pci_dev *dev);
 int char_init(void);
 void char_cleanup(void);
 
diff --git a/pci.c b/pci.c
index 3850633..ef6d5bf 100644
--- a/pci.c
+++ b/pci.c
@@ -11,7 +11,7 @@
 int doom_probe(struct pci_dev *dev, const struct pci_device_id *id)
 {
 	int err = 0;
-	ORFAIL(new_doomdev(), error_doomdev);
+	ORFAIL(new_doomdev(dev), error_doomdev);
 
 error_doomdev:
 	return err;
@@ -19,7 +19,7 @@ error_doomdev:
 
 void doom_remove (struct pci_dev *dev)
 {
-	destroy_doomdev();
+	destroy_doomdev(dev);
 }
 
 int doom_suspend (struct pci_dev *dev, pm_message_t state)
diff --git a/pci.h b/pci.h
index 377530e..04c48f2 100644
--- a/pci.h
+++ b/pci.h
@@ -1,6 +1,10 @@
 #ifndef PCI_H
 #define PCI_H
 
+struct doom_data {
+	int minor;
+};
+
 int pci_init(void);
 void pci_cleanup(void);
 
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