Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / crypto / scatterwalk.c

diff --git a/kernel/crypto/scatterwalk.c b/kernel/crypto/scatterwalk.c
new file mode 100644 (file)
index 0000000..3bd749c
--- /dev/null
+++ b/kernel/crypto/scatterwalk.c
@@ -0,0 +1,148 @@
+/*
+ * Cryptographic API.
+ *
+ * Cipher operations.
+ *
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ *               2002 Adam J. Richter <adam@yggdrasil.com>
+ *               2004 Jean-Luc Cooke <jlcooke@certainkey.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+
+#include <crypto/scatterwalk.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/scatterlist.h>
+
+static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
+{
+       void *src = out ? buf : sgdata;
+       void *dst = out ? sgdata : buf;
+
+       memcpy(dst, src, nbytes);
+}
+
+void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg)
+{
+       walk->sg = sg;
+
+       BUG_ON(!sg->length);
+
+       walk->offset = sg->offset;
+}
+EXPORT_SYMBOL_GPL(scatterwalk_start);
+
+void *scatterwalk_map(struct scatter_walk *walk)
+{
+       return kmap_atomic(scatterwalk_page(walk)) +
+              offset_in_page(walk->offset);
+}
+EXPORT_SYMBOL_GPL(scatterwalk_map);
+
+static 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);
+               if (!PageSlab(page))
+                       flush_dcache_page(page);
+       }
+
+       if (more) {
+               walk->offset += PAGE_SIZE - 1;
+               walk->offset &= PAGE_MASK;
+               if (walk->offset >= walk->sg->offset + walk->sg->length)
+                       scatterwalk_start(walk, sg_next(walk->sg));
+       }
+}
+
+void scatterwalk_done(struct scatter_walk *walk, int out, int more)
+{
+       if (!(scatterwalk_pagelen(walk) & (PAGE_SIZE - 1)) || !more)
+               scatterwalk_pagedone(walk, out, more);
+}
+EXPORT_SYMBOL_GPL(scatterwalk_done);
+
+void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
+                           size_t nbytes, int out)
+{
+       for (;;) {
+               unsigned int len_this_page = scatterwalk_pagelen(walk);
+               u8 *vaddr;
+
+               if (len_this_page > nbytes)
+                       len_this_page = nbytes;
+
+               vaddr = scatterwalk_map(walk);
+               memcpy_dir(buf, vaddr, len_this_page, out);
+               scatterwalk_unmap(vaddr);
+
+               scatterwalk_advance(walk, len_this_page);
+
+               if (nbytes == len_this_page)
+                       break;
+
+               buf += len_this_page;
+               nbytes -= len_this_page;
+
+               scatterwalk_pagedone(walk, out, 1);
+       }
+}
+EXPORT_SYMBOL_GPL(scatterwalk_copychunks);
+
+void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
+                             unsigned int start, unsigned int nbytes, int out)
+{
+       struct scatter_walk walk;
+       unsigned int offset = 0;
+
+       if (!nbytes)
+               return;
+
+       for (;;) {
+               scatterwalk_start(&walk, sg);
+
+               if (start < offset + sg->length)
+                       break;
+
+               offset += sg->length;
+               sg = sg_next(sg);
+       }
+
+       scatterwalk_advance(&walk, start - offset);
+       scatterwalk_copychunks(buf, &walk, nbytes, out);
+       scatterwalk_done(&walk, out, 0);
+}
+EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy);
+
+int scatterwalk_bytes_sglen(struct scatterlist *sg, int num_bytes)
+{
+       int offset = 0, n = 0;
+
+       /* num_bytes is too small */
+       if (num_bytes < sg->length)
+               return -1;
+
+       do {
+               offset += sg->length;
+               n++;
+               sg = sg_next(sg);
+
+               /* num_bytes is too large */
+               if (unlikely(!sg && (num_bytes < offset)))
+                       return -1;
+       } while (sg && (num_bytes > offset));
+
+       return n;
+}
+EXPORT_SYMBOL_GPL(scatterwalk_bytes_sglen);