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-rw-r--r--include/crypto/scatterwalk.h115
1 files changed, 115 insertions, 0 deletions
diff --git a/include/crypto/scatterwalk.h b/include/crypto/scatterwalk.h
new file mode 100644
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+++ b/include/crypto/scatterwalk.h
@@ -0,0 +1,115 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Cryptographic scatter and gather helpers.
+ *
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ * Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
+ * Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
+ * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+
+#ifndef _CRYPTO_SCATTERWALK_H
+#define _CRYPTO_SCATTERWALK_H
+
+#include <crypto/algapi.h>
+#include <linux/highmem.h>
+#include <linux/kernel.h>
+#include <linux/scatterlist.h>
+
+static inline void scatterwalk_crypto_chain(struct scatterlist *head,
+ struct scatterlist *sg, int num)
+{
+ if (sg)
+ sg_chain(head, num, sg);
+ else
+ sg_mark_end(head);
+}
+
+static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
+{
+ unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
+ unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
+ return len_this_page > len ? len : len_this_page;
+}
+
+static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
+ unsigned int nbytes)
+{
+ unsigned int len_this_page = scatterwalk_pagelen(walk);
+ return nbytes > len_this_page ? len_this_page : nbytes;
+}
+
+static inline void scatterwalk_advance(struct scatter_walk *walk,
+ unsigned int nbytes)
+{
+ walk->offset += nbytes;
+}
+
+static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
+ unsigned int alignmask)
+{
+ return !(walk->offset & alignmask);
+}
+
+static inline struct page *scatterwalk_page(struct scatter_walk *walk)
+{
+ return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
+}
+
+static inline void scatterwalk_unmap(void *vaddr)
+{
+ kunmap_atomic(vaddr);
+}
+
+static inline void scatterwalk_start(struct scatter_walk *walk,
+ struct scatterlist *sg)
+{
+ walk->sg = sg;
+ walk->offset = sg->offset;
+}
+
+static inline void *scatterwalk_map(struct scatter_walk *walk)
+{
+ return kmap_atomic(scatterwalk_page(walk)) +
+ offset_in_page(walk->offset);
+}
+
+static inline void scatterwalk_pagedone(struct scatter_walk *walk, int out,
+ unsigned int more)
+{
+ if (out) {
+ struct page *page;
+
+ page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
+ /* Test ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE first as
+ * PageSlab cannot be optimised away per se due to
+ * use of volatile pointer.
+ */
+ if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE && !PageSlab(page))
+ flush_dcache_page(page);
+ }
+
+ if (more && walk->offset >= walk->sg->offset + walk->sg->length)
+ scatterwalk_start(walk, sg_next(walk->sg));
+}
+
+static inline void scatterwalk_done(struct scatter_walk *walk, int out,
+ int more)
+{
+ if (!more || walk->offset >= walk->sg->offset + walk->sg->length ||
+ !(walk->offset & (PAGE_SIZE - 1)))
+ scatterwalk_pagedone(walk, out, more);
+}
+
+void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
+ size_t nbytes, int out);
+void *scatterwalk_map(struct scatter_walk *walk);
+
+void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
+ unsigned int start, unsigned int nbytes, int out);
+
+struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
+ struct scatterlist *src,
+ unsigned int len);
+
+#endif /* _CRYPTO_SCATTERWALK_H */