[Suspend2][ 02/12] [Suspend2] Encryption buffer allocation.

[Nigel Cunningham <nigel@suspend2.net>]

Add support for allocating and freeing buffers used for encryption.

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

 kernel/power/encryption.c |   51 +++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 51 insertions(+), 0 deletions(-)

diff --git a/kernel/power/encryption.c b/kernel/power/encryption.c
index a90d3ca..45d325d 100644
--- a/kernel/power/encryption.c
+++ b/kernel/power/encryption.c
@@ -45,3 +45,54 @@ static unsigned int bufofs;
 
 static struct scatterlist suspend_crypt_sg[PAGE_SIZE/8];
        
+/* ---- Local buffer management ---- */
+
+/* allocate_local_buffer
+ *
+ * Description:	Allocates a page of memory for buffering output.
+ * Returns:	Int: Zero if successful, -ENONEM otherwise.
+ */
+static int allocate_local_buffer(void)
+{
+	if (!page_buffer) {
+		int i, remainder;
+		
+		page_buffer = (char *) get_zeroed_page(GFP_ATOMIC);
+	
+		if (!page_buffer) {
+			printk(KERN_ERR
+				"Failed to allocate the page buffer for "
+				"suspend2 encryption driver.\n");
+			return -ENOMEM;
+		}
+
+		for (i=0; i < (PAGE_SIZE / suspend_key_len); i++) {
+			suspend_crypt_sg[i].page = virt_to_page(page_buffer);
+			suspend_crypt_sg[i].offset = suspend_key_len * i;
+			suspend_crypt_sg[i].length = suspend_key_len;
+		}
+		
+		remainder = PAGE_SIZE % suspend_key_len;
+
+		if (remainder) {
+			suspend_crypt_sg[i].page = virt_to_page(page_buffer);
+			suspend_crypt_sg[i].offset = suspend_key_len * i;
+			suspend_crypt_sg[i].length = remainder;
+		}
+	}
+
+	return 0;
+}
+
+/* free_local_buffer
+ *
+ * Description:	Frees memory allocated for buffering output.
+ */
+static void free_local_buffer(void)
+{
+	if (page_buffer)
+		free_page((unsigned long) page_buffer);
+
+	page_buffer = NULL;
+}
+

--
Nigel Cunningham		nigel at suspend2 dot net