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Linux Device Driver Development Cookbook

You're reading from   Linux Device Driver Development Cookbook Learn kernel programming and build custom drivers for your embedded Linux applications

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Product type Paperback
Published in May 2019
Publisher Packt
ISBN-13 9781838558802
Length 356 pages
Edition 1st Edition
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Author (1):
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Rodolfo Giometti Rodolfo Giometti
Author Profile Icon Rodolfo Giometti
Rodolfo Giometti
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Toc

Table of Contents (14) Chapters Close

Preface 1. Installing the Development System FREE CHAPTER 2. A Peek Inside the Kernel 3. Working with Char Drivers 4. Using the Device Tree 5. Managing Interrupts and Concurrency 6. Miscellaneous Kernel Internals 7. Advanced Char Driver Operations 8. Additional Information: Working with Char Drivers 9. Additional Information: Using the Device Tree 10. Additional Information: Managing Interrupts and Concurrency 11. Additional Information: Miscellaneous Kernel Internals 12. Additional Information: Advanced Char Driver Operations 13. Other Books You May Enjoy

Locking with the process context

In this recipe, we will see how to protect data against the concurrent access of two or more processes to avoid race conditions.

How to do it...

To present a simple example about how to add a mutex to the chrdev driver, we can make a few modifications to it, as reported in the following.

  1. First, we have to add the mux mutex to the driver's main structure in the chrdev.h header file, as follows:
/* Main struct */
struct chrdev_device {
char label[NAME_LEN];
unsigned int busy : 1;
char *buf;
int read_only;

unsigned int id;
struct module *owner;
struct cdev cdev;
struct device *dev;

struct mutex mux;
};
All modifications presented here can be applied to the chrdev...
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