1 files changed, 282 insertions, 79 deletions

diff --git a/kernel/kfifo.c b/kernel/kfifo.c
index 3765ff3c1bbe..e92d519f93b1 100644
--- a/kernel/kfifo.c
+++ b/kernel/kfifo.c
@@ -1,6 +1,7 @@
 /*
- * A simple kernel FIFO implementation.
+ * A generic kernel FIFO implementation.
  *
+ * Copyright (C) 2009 Stefani Seibold <stefani@seibold.net>
  * Copyright (C) 2004 Stelian Pop <stelian@popies.net>
  *
  * This program is free software; you can redistribute it and/or modify
@@ -25,50 +26,48 @@
 #include <linux/err.h>
 #include <linux/kfifo.h>
 #include <linux/log2.h>
+#include <linux/uaccess.h>
+
+static void _kfifo_init(struct kfifo *fifo, unsigned char *buffer,
+		unsigned int size)
+{
+	fifo->buffer = buffer;
+	fifo->size = size;
+
+	kfifo_reset(fifo);
+}
 
 /**
- * kfifo_init - allocates a new FIFO using a preallocated buffer
+ * kfifo_init - initialize a FIFO using a preallocated buffer
+ * @fifo: the fifo to assign the buffer
  * @buffer: the preallocated buffer to be used.
  * @size: the size of the internal buffer, this have to be a power of 2.
- * @gfp_mask: get_free_pages mask, passed to kmalloc()
- * @lock: the lock to be used to protect the fifo buffer
  *
- * Do NOT pass the kfifo to kfifo_free() after use! Simply free the
- * &struct kfifo with kfree().
  */
-struct kfifo *kfifo_init(unsigned char *buffer, unsigned int size,
-			 gfp_t gfp_mask, spinlock_t *lock)
+void kfifo_init(struct kfifo *fifo, unsigned char *buffer, unsigned int size)
 {
-	struct kfifo *fifo;
-
 	/* size must be a power of 2 */
 	BUG_ON(!is_power_of_2(size));
 
-	fifo = kmalloc(sizeof(struct kfifo), gfp_mask);
-	if (!fifo)
-		return ERR_PTR(-ENOMEM);
-
-	fifo->buffer = buffer;
-	fifo->size = size;
-	fifo->in = fifo->out = 0;
-	fifo->lock = lock;
-
-	return fifo;
+	_kfifo_init(fifo, buffer, size);
 }
 EXPORT_SYMBOL(kfifo_init);
 
 /**
- * kfifo_alloc - allocates a new FIFO and its internal buffer
- * @size: the size of the internal buffer to be allocated.
+ * kfifo_alloc - allocates a new FIFO internal buffer
+ * @fifo: the fifo to assign then new buffer
+ * @size: the size of the buffer to be allocated, this have to be a power of 2.
  * @gfp_mask: get_free_pages mask, passed to kmalloc()
- * @lock: the lock to be used to protect the fifo buffer
+ *
+ * This function dynamically allocates a new fifo internal buffer
  *
  * The size will be rounded-up to a power of 2.
+ * The buffer will be release with kfifo_free().
+ * Return 0 if no error, otherwise the an error code
  */
-struct kfifo *kfifo_alloc(unsigned int size, gfp_t gfp_mask, spinlock_t *lock)
+int kfifo_alloc(struct kfifo *fifo, unsigned int size, gfp_t gfp_mask)
 {
 	unsigned char *buffer;
-	struct kfifo *ret;
 
 	/*
 	 * round up to the next power of 2, since our 'let the indices
@@ -80,48 +79,91 @@ struct kfifo *kfifo_alloc(unsigned int size, gfp_t gfp_mask, spinlock_t *lock)
 	}
 
 	buffer = kmalloc(size, gfp_mask);
-	if (!buffer)
-		return ERR_PTR(-ENOMEM);
-
-	ret = kfifo_init(buffer, size, gfp_mask, lock);
+	if (!buffer) {
+		_kfifo_init(fifo, 0, 0);
+		return -ENOMEM;
+	}
 
-	if (IS_ERR(ret))
-		kfree(buffer);
+	_kfifo_init(fifo, buffer, size);
 
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL(kfifo_alloc);
 
 /**
- * kfifo_free - frees the FIFO
+ * kfifo_free - frees the FIFO internal buffer
  * @fifo: the fifo to be freed.
  */
 void kfifo_free(struct kfifo *fifo)
 {
 	kfree(fifo->buffer);
-	kfree(fifo);
 }
 EXPORT_SYMBOL(kfifo_free);
 
 /**
- * __kfifo_put - puts some data into the FIFO, no locking version
+ * kfifo_skip - skip output data
  * @fifo: the fifo to be used.
- * @buffer: the data to be added.
- * @len: the length of the data to be added.
- *
- * This function copies at most @len bytes from the @buffer into
- * the FIFO depending on the free space, and returns the number of
- * bytes copied.
- *
- * Note that with only one concurrent reader and one concurrent
- * writer, you don't need extra locking to use these functions.
+ * @len: number of bytes to skip
  */
-unsigned int __kfifo_put(struct kfifo *fifo,
-			const unsigned char *buffer, unsigned int len)
+void kfifo_skip(struct kfifo *fifo, unsigned int len)
+{
+	if (len < kfifo_len(fifo)) {
+		__kfifo_add_out(fifo, len);
+		return;
+	}
+	kfifo_reset_out(fifo);
+}
+EXPORT_SYMBOL(kfifo_skip);
+
+static inline void __kfifo_in_data(struct kfifo *fifo,
+		const void *from, unsigned int len, unsigned int off)
 {
 	unsigned int l;
 
-	len = min(len, fifo->size - fifo->in + fifo->out);
+	/*
+	 * Ensure that we sample the fifo->out index -before- we
+	 * start putting bytes into the kfifo.
+	 */
+
+	smp_mb();
+
+	off = __kfifo_off(fifo, fifo->in + off);
+
+	/* first put the data starting from fifo->in to buffer end */
+	l = min(len, fifo->size - off);
+	memcpy(fifo->buffer + off, from, l);
+
+	/* then put the rest (if any) at the beginning of the buffer */
+	memcpy(fifo->buffer, from + l, len - l);
+}
+
+static inline void __kfifo_out_data(struct kfifo *fifo,
+		void *to, unsigned int len, unsigned int off)
+{
+	unsigned int l;
+
+	/*
+	 * Ensure that we sample the fifo->in index -before- we
+	 * start removing bytes from the kfifo.
+	 */
+
+	smp_rmb();
+
+	off = __kfifo_off(fifo, fifo->out + off);
+
+	/* first get the data from fifo->out until the end of the buffer */
+	l = min(len, fifo->size - off);
+	memcpy(to, fifo->buffer + off, l);
+
+	/* then get the rest (if any) from the beginning of the buffer */
+	memcpy(to + l, fifo->buffer, len - l);
+}
+
+static inline unsigned int __kfifo_from_user_data(struct kfifo *fifo,
+	 const void __user *from, unsigned int len, unsigned int off)
+{
+	unsigned int l;
+	int ret;
 
 	/*
 	 * Ensure that we sample the fifo->out index -before- we
@@ -130,68 +172,229 @@ unsigned int __kfifo_put(struct kfifo *fifo,
 
 	smp_mb();
 
+	off = __kfifo_off(fifo, fifo->in + off);
+
 	/* first put the data starting from fifo->in to buffer end */
-	l = min(len, fifo->size - (fifo->in & (fifo->size - 1)));
-	memcpy(fifo->buffer + (fifo->in & (fifo->size - 1)), buffer, l);
+	l = min(len, fifo->size - off);
+	ret = copy_from_user(fifo->buffer + off, from, l);
+
+	if (unlikely(ret))
+		return ret + len - l;
 
 	/* then put the rest (if any) at the beginning of the buffer */
-	memcpy(fifo->buffer, buffer + l, len - l);
+	return copy_from_user(fifo->buffer, from + l, len - l);
+}
+
+static inline unsigned int __kfifo_to_user_data(struct kfifo *fifo,
+		void __user *to, unsigned int len, unsigned int off)
+{
+	unsigned int l;
+	int ret;
 
 	/*
-	 * Ensure that we add the bytes to the kfifo -before-
-	 * we update the fifo->in index.
+	 * Ensure that we sample the fifo->in index -before- we
+	 * start removing bytes from the kfifo.
 	 */
 
-	smp_wmb();
+	smp_rmb();
+
+	off = __kfifo_off(fifo, fifo->out + off);
+
+	/* first get the data from fifo->out until the end of the buffer */
+	l = min(len, fifo->size - off);
+	ret = copy_to_user(to, fifo->buffer + off, l);
+
+	if (unlikely(ret))
+		return ret + len - l;
+
+	/* then get the rest (if any) from the beginning of the buffer */
+	return copy_to_user(to + l, fifo->buffer, len - l);
+}
+
+unsigned int __kfifo_in_n(struct kfifo *fifo,
+	const void *from, unsigned int len, unsigned int recsize)
+{
+	if (kfifo_avail(fifo) < len + recsize)
+		return len + 1;
+
+	__kfifo_in_data(fifo, from, len, recsize);
+	return 0;
+}
+EXPORT_SYMBOL(__kfifo_in_n);
 
-	fifo->in += len;
+/**
+ * kfifo_in - puts some data into the FIFO
+ * @fifo: the fifo to be used.
+ * @from: the data to be added.
+ * @len: the length of the data to be added.
+ *
+ * This function copies at most @len bytes from the @from buffer into
+ * the FIFO depending on the free space, and returns the number of
+ * bytes copied.
+ *
+ * Note that with only one concurrent reader and one concurrent
+ * writer, you don't need extra locking to use these functions.
+ */
+unsigned int kfifo_in(struct kfifo *fifo, const unsigned char *from,
+				unsigned int len)
+{
+	len = min(kfifo_avail(fifo), len);
 
+	__kfifo_in_data(fifo, from, len, 0);
+	__kfifo_add_in(fifo, len);
 	return len;
 }
-EXPORT_SYMBOL(__kfifo_put);
+EXPORT_SYMBOL(kfifo_in);
+
+unsigned int __kfifo_in_generic(struct kfifo *fifo,
+	const void *from, unsigned int len, unsigned int recsize)
+{
+	return __kfifo_in_rec(fifo, from, len, recsize);
+}
+EXPORT_SYMBOL(__kfifo_in_generic);
+
+unsigned int __kfifo_out_n(struct kfifo *fifo,
+	void *to, unsigned int len, unsigned int recsize)
+{
+	if (kfifo_len(fifo) < len + recsize)
+		return len;
+
+	__kfifo_out_data(fifo, to, len, recsize);
+	__kfifo_add_out(fifo, len + recsize);
+	return 0;
+}
+EXPORT_SYMBOL(__kfifo_out_n);
 
 /**
- * __kfifo_get - gets some data from the FIFO, no locking version
+ * kfifo_out - gets some data from the FIFO
  * @fifo: the fifo to be used.
- * @buffer: where the data must be copied.
+ * @to: where the data must be copied.
  * @len: the size of the destination buffer.
  *
  * This function copies at most @len bytes from the FIFO into the
- * @buffer and returns the number of copied bytes.
+ * @to buffer and returns the number of copied bytes.
  *
  * Note that with only one concurrent reader and one concurrent
  * writer, you don't need extra locking to use these functions.
  */
-unsigned int __kfifo_get(struct kfifo *fifo,
-			 unsigned char *buffer, unsigned int len)
+unsigned int kfifo_out(struct kfifo *fifo, unsigned char *to, unsigned int len)
 {
-	unsigned int l;
+	len = min(kfifo_len(fifo), len);
 
-	len = min(len, fifo->in - fifo->out);
+	__kfifo_out_data(fifo, to, len, 0);
+	__kfifo_add_out(fifo, len);
 
-	/*
-	 * Ensure that we sample the fifo->in index -before- we
-	 * start removing bytes from the kfifo.
-	 */
+	return len;
+}
+EXPORT_SYMBOL(kfifo_out);
 
-	smp_rmb();
+unsigned int __kfifo_out_generic(struct kfifo *fifo,
+	void *to, unsigned int len, unsigned int recsize,
+	unsigned int *total)
+{
+	return __kfifo_out_rec(fifo, to, len, recsize, total);
+}
+EXPORT_SYMBOL(__kfifo_out_generic);
 
-	/* first get the data from fifo->out until the end of the buffer */
-	l = min(len, fifo->size - (fifo->out & (fifo->size - 1)));
-	memcpy(buffer, fifo->buffer + (fifo->out & (fifo->size - 1)), l);
+unsigned int __kfifo_from_user_n(struct kfifo *fifo,
+	const void __user *from, unsigned int len, unsigned int recsize)
+{
+	if (kfifo_avail(fifo) < len + recsize)
+		return len + 1;
 
-	/* then get the rest (if any) from the beginning of the buffer */
-	memcpy(buffer + l, fifo->buffer, len - l);
+	return __kfifo_from_user_data(fifo, from, len, recsize);
+}
+EXPORT_SYMBOL(__kfifo_from_user_n);
 
-	/*
-	 * Ensure that we remove the bytes from the kfifo -before-
-	 * we update the fifo->out index.
-	 */
+/**
+ * kfifo_from_user - puts some data from user space into the FIFO
+ * @fifo: the fifo to be used.
+ * @from: pointer to the data to be added.
+ * @len: the length of the data to be added.
+ *
+ * This function copies at most @len bytes from the @from into the
+ * FIFO depending and returns the number of copied bytes.
+ *
+ * Note that with only one concurrent reader and one concurrent
+ * writer, you don't need extra locking to use these functions.
+ */
+unsigned int kfifo_from_user(struct kfifo *fifo,
+	const void __user *from, unsigned int len)
+{
+	len = min(kfifo_avail(fifo), len);
+	len -= __kfifo_from_user_data(fifo, from, len, 0);
+	__kfifo_add_in(fifo, len);
+	return len;
+}
+EXPORT_SYMBOL(kfifo_from_user);
 
-	smp_mb();
+unsigned int __kfifo_from_user_generic(struct kfifo *fifo,
+	const void __user *from, unsigned int len, unsigned int recsize)
+{
+	return __kfifo_from_user_rec(fifo, from, len, recsize);
+}
+EXPORT_SYMBOL(__kfifo_from_user_generic);
 
-	fifo->out += len;
+unsigned int __kfifo_to_user_n(struct kfifo *fifo,
+	void __user *to, unsigned int len, unsigned int reclen,
+	unsigned int recsize)
+{
+	unsigned int ret;
+
+	if (kfifo_len(fifo) < reclen + recsize)
+		return len;
+
+	ret = __kfifo_to_user_data(fifo, to, reclen, recsize);
 
+	if (likely(ret == 0))
+		__kfifo_add_out(fifo, reclen + recsize);
+
+	return ret;
+}
+EXPORT_SYMBOL(__kfifo_to_user_n);
+
+/**
+ * kfifo_to_user - gets data from the FIFO and write it to user space
+ * @fifo: the fifo to be used.
+ * @to: where the data must be copied.
+ * @len: the size of the destination buffer.
+ *
+ * This function copies at most @len bytes from the FIFO into the
+ * @to buffer and returns the number of copied bytes.
+ *
+ * Note that with only one concurrent reader and one concurrent
+ * writer, you don't need extra locking to use these functions.
+ */
+unsigned int kfifo_to_user(struct kfifo *fifo,
+	void __user *to, unsigned int len)
+{
+	len = min(kfifo_len(fifo), len);
+	len -= __kfifo_to_user_data(fifo, to, len, 0);
+	__kfifo_add_out(fifo, len);
 	return len;
 }
-EXPORT_SYMBOL(__kfifo_get);
+EXPORT_SYMBOL(kfifo_to_user);
+
+unsigned int __kfifo_to_user_generic(struct kfifo *fifo,
+	void __user *to, unsigned int len, unsigned int recsize,
+	unsigned int *total)
+{
+	return __kfifo_to_user_rec(fifo, to, len, recsize, total);
+}
+EXPORT_SYMBOL(__kfifo_to_user_generic);
+
+unsigned int __kfifo_peek_generic(struct kfifo *fifo, unsigned int recsize)
+{
+	if (recsize == 0)
+		return kfifo_avail(fifo);
+
+	return __kfifo_peek_n(fifo, recsize);
+}
+EXPORT_SYMBOL(__kfifo_peek_generic);
+
+void __kfifo_skip_generic(struct kfifo *fifo, unsigned int recsize)
+{
+	__kfifo_skip_rec(fifo, recsize);
+}
+EXPORT_SYMBOL(__kfifo_skip_generic);
+