X-Git-Url: https://bbs.cooldavid.org/git/?a=blobdiff_plain;f=samples%2Fkfifo%2Finttype-example.c;fp=samples%2Fkfifo%2Finttype-example.c;h=d6c5b7d9df64ada598c500bc2e1293200fffe006;hb=5bf2b19320ec31d094d7370fdf536f7fd91fd799;hp=0000000000000000000000000000000000000000;hpb=2e956fb320568cc70861761483e2f0e2db75fd66;p=net-next-2.6.git diff --git a/samples/kfifo/inttype-example.c b/samples/kfifo/inttype-example.c new file mode 100644 index 00000000000..d6c5b7d9df6 --- /dev/null +++ b/samples/kfifo/inttype-example.c @@ -0,0 +1,157 @@ +/* + * Sample kfifo int type implementation + * + * Copyright (C) 2010 Stefani Seibold + * + * Released under the GPL version 2 only. + * + */ + +#include +#include +#include +#include +#include + +/* + * This module shows how to create a int type fifo. + */ + +/* fifo size in elements (ints) */ +#define FIFO_SIZE 32 + +/* name of the proc entry */ +#define PROC_FIFO "int-fifo" + +/* lock for procfs read access */ +static DEFINE_MUTEX(read_lock); + +/* lock for procfs write access */ +static DEFINE_MUTEX(write_lock); + +/* + * define DYNAMIC in this example for a dynamically allocated fifo. + * + * Otherwise the fifo storage will be a part of the fifo structure. + */ +#if 0 +#define DYNAMIC +#endif + +#ifdef DYNAMIC +static DECLARE_KFIFO_PTR(test, int); +#else +static DEFINE_KFIFO(test, int, FIFO_SIZE); +#endif + +static int __init testfunc(void) +{ + int buf[6]; + int i; + unsigned int ret; + + printk(KERN_INFO "int fifo test start\n"); + + /* put values into the fifo */ + for (i = 0; i != 10; i++) + kfifo_put(&test, &i); + + /* show the number of used elements */ + printk(KERN_INFO "fifo len: %u\n", kfifo_len(&test)); + + /* get max of 2 elements from the fifo */ + ret = kfifo_out(&test, buf, 2); + printk(KERN_INFO "ret: %d\n", ret); + /* and put it back to the end of the fifo */ + ret = kfifo_in(&test, buf, ret); + printk(KERN_INFO "ret: %d\n", ret); + + for (i = 20; i != 30; i++) + kfifo_put(&test, &i); + + printk(KERN_INFO "queue len: %u\n", kfifo_len(&test)); + + /* show the first value without removing from the fifo */ + if (kfifo_peek(&test, &i)) + printk(KERN_INFO "%d\n", i); + + /* print out all values in the fifo */ + while (kfifo_get(&test, &i)) + printk("%d ", i); + printk("\n"); + + return 0; +} + +static ssize_t fifo_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + int ret; + unsigned int copied; + + if (mutex_lock_interruptible(&write_lock)) + return -ERESTARTSYS; + + ret = kfifo_from_user(&test, buf, count, &copied); + + mutex_unlock(&write_lock); + + return ret ? ret : copied; +} + +static ssize_t fifo_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + int ret; + unsigned int copied; + + if (mutex_lock_interruptible(&read_lock)) + return -ERESTARTSYS; + + ret = kfifo_to_user(&test, buf, count, &copied); + + mutex_unlock(&read_lock); + + return ret ? ret : copied; +} + +static const struct file_operations fifo_fops = { + .owner = THIS_MODULE, + .read = fifo_read, + .write = fifo_write, +}; + +static int __init example_init(void) +{ +#ifdef DYNAMIC + int ret; + + ret = kfifo_alloc(&test, FIFO_SIZE, GFP_KERNEL); + if (ret) { + printk(KERN_ERR "error kfifo_alloc\n"); + return ret; + } +#endif + testfunc(); + + if (proc_create(PROC_FIFO, 0, NULL, &fifo_fops) == NULL) { +#ifdef DYNAMIC + kfifo_free(&test); +#endif + return -ENOMEM; + } + return 0; +} + +static void __exit example_exit(void) +{ + remove_proc_entry(PROC_FIFO, NULL); +#ifdef DYNAMIC + kfifo_free(&test); +#endif +} + +module_init(example_init); +module_exit(example_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Stefani Seibold ");