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-rw-r--r--include/crypto/scatterwalk.h17
1 files changed, 17 insertions, 0 deletions
diff --git a/include/crypto/scatterwalk.h b/include/crypto/scatterwalk.h
index 1689ecd7ddaf..f6262d05a3c7 100644
--- a/include/crypto/scatterwalk.h
+++ b/include/crypto/scatterwalk.h
@@ -69,6 +69,23 @@ static inline struct page *scatterwalk_page(struct scatter_walk *walk)
return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
}
+/*
+ * Create a scatterlist that represents the remaining data in a walk. Uses
+ * chaining to reference the original scatterlist, so this uses at most two
+ * entries in @sg_out regardless of the number of entries in the original list.
+ * Assumes that sg_init_table() was already done.
+ */
+static inline void scatterwalk_get_sglist(struct scatter_walk *walk,
+ struct scatterlist sg_out[2])
+{
+ if (walk->offset >= walk->sg->offset + walk->sg->length)
+ scatterwalk_start(walk, sg_next(walk->sg));
+ sg_set_page(sg_out, sg_page(walk->sg),
+ walk->sg->offset + walk->sg->length - walk->offset,
+ walk->offset);
+ scatterwalk_crypto_chain(sg_out, sg_next(walk->sg), 2);
+}
+
static inline void scatterwalk_unmap(void *vaddr)
{
kunmap_local(vaddr);