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authorJens Axboe <jens.axboe@oracle.com>2007-05-09 09:02:57 +0200
committerJens Axboe <jens.axboe@oracle.com>2007-10-16 11:07:10 +0200
commit96b418c960af0d5c7185ff5c4af9376eb37ac9d3 (patch)
treec909c9d317262cadb37357e0e13d7c2922cfebc0
parentab83407e9ee35a4972457aa487be6a7a21afd715 (diff)
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>
-rw-r--r--include/linux/scatterlist.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 4efbd9c445f5..bed5ab4d756a 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 */