From: Jens Axboe <jens.axboe@oracle.com>
Date: Wed, 9 May 2007 07:02:57 +0000 (+0200)
Subject: Add sg helpers for iterating over a scatterlist table
X-Git-Tag: v2.6.24-rc1~833^2~1^2~44
X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=96b418c960af0d5c7185ff5c4af9376eb37ac9d3;p=linux-2.6-omap-h63xx.git

Add sg helpers for iterating over a scatterlist table

First step to being able to change the scatterlist setup without
having to modify drivers (a lot :-)

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 4efbd9c445f..bed5ab4d756 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -20,4 +20,13 @@ static inline void sg_init_one(struct scatterlist *sg, const void *buf,
 	sg_set_buf(sg, buf, buflen);
 }
 
+#define sg_next(sg)		((sg) + 1)
+#define sg_last(sg, nents)	(&(sg[(nents) - 1]))
+
+/*
+ * Loop over each sg element, following the pointer to a new list if necessary
+ */
+#define for_each_sg(sglist, sg, nr, __i)	\
+	for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg))
+
 #endif /* _LINUX_SCATTERLIST_H */