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-rw-r--r--kernel/kfifo.c65
1 files changed, 33 insertions, 32 deletions
diff --git a/kernel/kfifo.c b/kernel/kfifo.c
index 3765ff3c1bb..8da6bb9782b 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
@@ -26,49 +27,51 @@
#include <linux/kfifo.h>
#include <linux/log2.h>
+static void _kfifo_init(struct kfifo *fifo, unsigned char *buffer,
+ unsigned int size, spinlock_t *lock)
+{
+ fifo->buffer = buffer;
+ fifo->size = size;
+ fifo->lock = lock;
+
+ 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,
+ spinlock_t *lock)
{
- 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, lock);
}
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,
+ spinlock_t *lock)
{
unsigned char *buffer;
- struct kfifo *ret;
/*
* round up to the next power of 2, since our 'let the indices
@@ -80,26 +83,24 @@ 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, NULL);
+ return -ENOMEM;
+ }
- if (IS_ERR(ret))
- kfree(buffer);
+ _kfifo_init(fifo, buffer, size, lock);
- 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);