On Wednesday 30 January 2013 12:37:25 Kurachkin Michail wrote:
> Hi Greg,
>
> I followed your recommendations and created a diff using Linux 3.8-rc5
> sources. Please review it and give your comments.
Hi,
given the size of the thing I hope you don't mind a review in parts.
Here we go.
Do you really need all those helpers? At a minimum they should become static
to not pollute common namespaces.
Regards
Oliver
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include "fifo.h"
+
+static void inc_pointer(int *pointer, int item_size, int count_items);
+
+
+/**
+ * Init circular fifo buffer
+ * @param buf - buffer descriptor
+ * @param item_size - item size in bytes
+ * @param count - count items in buffer
+ * @return 0 - ok
+ */
+int init_fifo(struct fifo_buffer *fifo, int item_size, int count)
+{
+ fifo->read_pointer = 0;
+ fifo->write_pointer = 0;
+
+ fifo->buf = kzalloc(item_size * count, GFP_KERNEL);
+ if(!fifo->buf)
+ return -ENOMEM;
+
+ fifo->count = count;
+ fifo->item_size = item_size;
+ memset(fifo->buf, 0, item_size * count);
+ return 0;
+}
+
+
+/**
+ * free fifo buffer
+ * @param fifo
+ */
+void free_fifo(struct fifo_buffer *fifo)
+{
+ if(!fifo)
+ return;
+
+ if(!fifo->buf) {
+ kfree(fifo);
+ return;
+ }
+
+ kfree(fifo->buf);
+}
+
+
+/**
+ * Push into fifo
+ * @param fifo - fifo descriptor
+ * @param item - pointer to item
+ * @return 0 - ok, 1 - item pushed and buffer is full
+ */
+int fifo_push(struct fifo_buffer *fifo, void *item)
+{
+ memcpy(fifo->buf + fifo->write_pointer, item, fifo->item_size);
+
+ inc_pointer(&fifo->write_pointer, fifo->item_size, fifo->count);
+
+ if(fifo->write_pointer == fifo->read_pointer) { // If fifo is full
+ inc_pointer(&fifo->read_pointer, fifo->item_size, fifo->count);
+ return 1;
+ }
+
+ return 0;
+}
+
+
+/**
+ * Check fifo buffer is full
+ * @param fifo - fifo descriptor
+ * @return 1 - buffer is full
+ */
+int fifo_is_full(struct fifo_buffer *fifo)
+{
+ int p;
+ p = fifo->write_pointer;
+ inc_pointer(&p, fifo->item_size, fifo->count);
+ if(p == fifo->read_pointer)
+ return 1;
+
+ return 0;
+}
+
+
+/**
+ * Check fifo is empty
+ * @param fifo - fifo descriptor
+ * @return 1 - buffer is empty
+ */
+int fifo_is_empty(struct fifo_buffer *fifo)
+{
+ return fifo->read_pointer == fifo->write_pointer;
+}
+
+
+/**
+ * Pop from fifo buffer
+ * @param fifo - fifo descriptor
+ * @param item - pointer to poped item
+ * @return 0 - ok, 1 - buffer is empty
+ */
+int fifo_pop(struct fifo_buffer *fifo, void *item)
+{
+ if(fifo->read_pointer == fifo->write_pointer)
+ return 1;
+
+ memcpy(item, fifo->buf + fifo->read_pointer, fifo->item_size);
+ inc_pointer(&fifo->read_pointer, fifo->item_size, fifo->count);
+ return 0;
+}
+
+
+/**
+ * Increment pointer in circular buffer
+ * @param pointer - pointer in circular buffer
+ * @param item_size - item size in bytes
+ * @param count_items - count items in fifo
+ */
+static void inc_pointer(int *pointer, int item_size, int count_items)
+{
+ (*pointer) += item_size;
+
+ if(*pointer >= (count_items * item_size))
+ *pointer = 0;
+}
+
--
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