Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 202 insertions, 0 deletions

diff --git a/samples/kfifo/record-example.c b/samples/kfifo/record-example.c
new file mode 100644
index 000000000..f64f3d62d
--- /dev/null
+++ b/samples/kfifo/record-example.c
@@ -0,0 +1,202 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Sample dynamic sized record fifo implementation
+ *
+ * Copyright (C) 2010 Stefani Seibold <stefani@seibold.net>
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/mutex.h>
+#include <linux/kfifo.h>
+
+/*
+ * This module shows how to create a variable sized record fifo.
+ */
+
+/* fifo size in elements (bytes) */
+#define FIFO_SIZE	128
+
+/* name of the proc entry */
+#define	PROC_FIFO	"record-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
+
+/*
+ * struct kfifo_rec_ptr_1 and  STRUCT_KFIFO_REC_1 can handle records of a
+ * length between 0 and 255 bytes.
+ *
+ * struct kfifo_rec_ptr_2 and  STRUCT_KFIFO_REC_2 can handle records of a
+ * length between 0 and 65535 bytes.
+ */
+
+#ifdef DYNAMIC
+struct kfifo_rec_ptr_1 test;
+
+#else
+typedef STRUCT_KFIFO_REC_1(FIFO_SIZE) mytest;
+
+static mytest test;
+#endif
+
+static const char *expected_result[] = {
+	"a",
+	"bb",
+	"ccc",
+	"dddd",
+	"eeeee",
+	"ffffff",
+	"ggggggg",
+	"hhhhhhhh",
+	"iiiiiiiii",
+	"jjjjjjjjjj",
+};
+
+static int __init testfunc(void)
+{
+	char		buf[100];
+	unsigned int	i;
+	unsigned int	ret;
+	struct { unsigned char buf[6]; } hello = { "hello" };
+
+	printk(KERN_INFO "record fifo test start\n");
+
+	kfifo_in(&test, &hello, sizeof(hello));
+
+	/* show the size of the next record in the fifo */
+	printk(KERN_INFO "fifo peek len: %u\n", kfifo_peek_len(&test));
+
+	/* put in variable length data */
+	for (i = 0; i < 10; i++) {
+		memset(buf, 'a' + i, i + 1);
+		kfifo_in(&test, buf, i + 1);
+	}
+
+	/* skip first element of the fifo */
+	printk(KERN_INFO "skip 1st element\n");
+	kfifo_skip(&test);
+
+	printk(KERN_INFO "fifo len: %u\n", kfifo_len(&test));
+
+	/* show the first record without removing from the fifo */
+	ret = kfifo_out_peek(&test, buf, sizeof(buf));
+	if (ret)
+		printk(KERN_INFO "%.*s\n", ret, buf);
+
+	/* check the correctness of all values in the fifo */
+	i = 0;
+	while (!kfifo_is_empty(&test)) {
+		ret = kfifo_out(&test, buf, sizeof(buf));
+		buf[ret] = '\0';
+		printk(KERN_INFO "item = %.*s\n", ret, buf);
+		if (strcmp(buf, expected_result[i++])) {
+			printk(KERN_WARNING "value mismatch: test failed\n");
+			return -EIO;
+		}
+	}
+	if (i != ARRAY_SIZE(expected_result)) {
+		printk(KERN_WARNING "size mismatch: test failed\n");
+		return -EIO;
+	}
+	printk(KERN_INFO "test passed\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);
+	if (ret)
+		return ret;
+
+	return 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);
+	if (ret)
+		return ret;
+
+	return copied;
+}
+
+static const struct proc_ops fifo_proc_ops = {
+	.proc_read	= fifo_read,
+	.proc_write	= fifo_write,
+	.proc_lseek	= noop_llseek,
+};
+
+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;
+	}
+#else
+	INIT_KFIFO(test);
+#endif
+	if (testfunc() < 0) {
+#ifdef DYNAMIC
+		kfifo_free(&test);
+#endif
+		return -EIO;
+	}
+
+	if (proc_create(PROC_FIFO, 0, NULL, &fifo_proc_ops) == 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 <stefani@seibold.net>");