[Suspend2][ 02/13] [Suspend2] Allocate compression buffers.

[Nigel Cunningham <nigel@suspend2.net>]

The compression module uses a couple of local buffers to cache partially
filled output pages, and to receive the cryptoapi output. These routines
are responsible for allocating and freeing those buffers.

Signed-off-by: Nigel Cunningham <nigel@suspend2.net>

 kernel/power/compression.c |   53 ++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 53 insertions(+), 0 deletions(-)

diff --git a/kernel/power/compression.c b/kernel/power/compression.c
index 72075d7..3d222b3 100644
--- a/kernel/power/compression.c
+++ b/kernel/power/compression.c
@@ -39,3 +39,56 @@ static unsigned int bufofs;
 
 static int position = 0;
        
+/* ---- Local buffer management ---- */
+
+/* 
+ * suspend_compress_allocate_local_buffer
+ *
+ * Allocates a page of memory for buffering output.
+ * Int: Zero if successful, -ENONEM otherwise.
+ */
+static int suspend_compress_allocate_local_buffer(void)
+{
+	if (!local_buffer) {
+		local_buffer = (char *) get_zeroed_page(GFP_ATOMIC);
+	
+		if (!local_buffer) {
+			printk(KERN_ERR
+				"Failed to allocate the local buffer for "
+				"suspend2 compression driver.\n");
+			return -ENOMEM;
+		}
+	}
+
+	if (!page_buffer) {
+		page_buffer = (char *) get_zeroed_page(GFP_ATOMIC);
+	
+		if (!page_buffer) {
+			printk(KERN_ERR
+				"Failed to allocate the page buffer for "
+				"suspend2 compression driver.\n");
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
+/* 
+ * suspend_compress_free_local_buffer
+ *
+ * Frees memory allocated for buffering output.
+ */
+static inline void suspend_compress_free_local_buffer(void)
+{
+	if (local_buffer)
+		free_page((unsigned long) local_buffer);
+
+	local_buffer = NULL;
+
+	if (page_buffer)
+		free_page((unsigned long) page_buffer);
+
+	page_buffer = NULL;
+}
+

--
Nigel Cunningham		nigel at suspend2 dot net