RDS: fix the sg allocation based on actual message size

Fix an issue where only PAGE_SIZE bytes are allocated per
scatter-gather entry (SGE) regardless of the actual message
size: Furthermore, use buddy memory allocation technique to
allocate/free memmory (if possible) to reduce SGE.

Orabug: 21894138
Signed-off-by: Wei Lin Guay <[email protected]>
Signed-off-by: Santosh Shilimkar <[email protected]>

Author: Wei Lin Guay

net/rds/message.c

@@ -63,7 +63,10 @@ static void rds_message_purge(struct rds_message *rm)
 	for (i = 0; i < rm->data.op_nents; i++) {
 		rdsdebug("putting data page %p\n", (void *)sg_page(&rm->data.op_sg[i]));
 		/* XXX will have to put_page for page refs */
-		__free_page(sg_page(&rm->data.op_sg[i]));
+		(rm->data.op_sg[i].length <= PAGE_SIZE) ?
+			__free_page(sg_page(&rm->data.op_sg[i])) :
+			__free_pages(sg_page(&rm->data.op_sg[i]),
+				     get_order(rm->data.op_sg[i].length));
 	}
 	rm->data.op_nents = 0;
 

net/rds/page.c

@@ -127,11 +127,11 @@ int rds_page_remainder_alloc(struct scatterlist *scat, unsigned long bytes,
 
 	/* jump straight to allocation if we're trying for a huge page */
 	if (bytes >= PAGE_SIZE) {
-		page = alloc_page(gfp);
+		page = alloc_pages(gfp, get_order(bytes));
 		if (!page) {
 			ret = -ENOMEM;
 		} else {
-			sg_set_page(scat, page, PAGE_SIZE, 0);
+			sg_set_page(scat, page, bytes, 0);
 			ret = 0;
 		}
 		goto out;