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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /crypto/scatterwalk.c
downloadlinux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'crypto/scatterwalk.c')
-rw-r--r--crypto/scatterwalk.c115
1 files changed, 115 insertions, 0 deletions
diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
new file mode 100644
index 00000000000..50c9461e8cc
--- /dev/null
+++ b/crypto/scatterwalk.c
@@ -0,0 +1,115 @@
+/*
+ * 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 <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <asm/bug.h>
+#include <asm/scatterlist.h>
+#include "internal.h"
+#include "scatterwalk.h"
+
+enum km_type crypto_km_types[] = {
+ KM_USER0,
+ KM_USER1,
+ KM_SOFTIRQ0,
+ KM_SOFTIRQ1,
+};
+
+static void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
+{
+ if (out)
+ memcpy(sgdata, buf, nbytes);
+ else
+ memcpy(buf, sgdata, nbytes);
+}
+
+void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg)
+{
+ unsigned int rest_of_page;
+
+ walk->sg = sg;
+
+ walk->page = sg->page;
+ walk->len_this_segment = sg->length;
+
+ BUG_ON(!sg->length);
+
+ rest_of_page = PAGE_CACHE_SIZE - (sg->offset & (PAGE_CACHE_SIZE - 1));
+ walk->len_this_page = min(sg->length, rest_of_page);
+ walk->offset = sg->offset;
+}
+
+void scatterwalk_map(struct scatter_walk *walk, int out)
+{
+ walk->data = crypto_kmap(walk->page, out) + walk->offset;
+}
+
+static inline void scatterwalk_unmap(struct scatter_walk *walk, int out)
+{
+ /* walk->data may be pointing the first byte of the next page;
+ however, we know we transfered at least one byte. So,
+ walk->data - 1 will be a virtual address in the mapped page. */
+ crypto_kunmap(walk->data - 1, out);
+}
+
+static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
+ unsigned int more)
+{
+ if (out)
+ flush_dcache_page(walk->page);
+
+ if (more) {
+ walk->len_this_segment -= walk->len_this_page;
+
+ if (walk->len_this_segment) {
+ walk->page++;
+ walk->len_this_page = min(walk->len_this_segment,
+ (unsigned)PAGE_CACHE_SIZE);
+ walk->offset = 0;
+ }
+ else
+ scatterwalk_start(walk, sg_next(walk->sg));
+ }
+}
+
+void scatterwalk_done(struct scatter_walk *walk, int out, int more)
+{
+ scatterwalk_unmap(walk, out);
+ if (walk->len_this_page == 0 || !more)
+ scatterwalk_pagedone(walk, out, more);
+}
+
+/*
+ * Do not call this unless the total length of all of the fragments
+ * has been verified as multiple of the block size.
+ */
+int scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
+ size_t nbytes, int out)
+{
+ do {
+ memcpy_dir(buf, walk->data, walk->len_this_page, out);
+ buf += walk->len_this_page;
+ nbytes -= walk->len_this_page;
+
+ scatterwalk_unmap(walk, out);
+ scatterwalk_pagedone(walk, out, 1);
+ scatterwalk_map(walk, out);
+ } while (nbytes > walk->len_this_page);
+
+ memcpy_dir(buf, walk->data, nbytes, out);
+ return nbytes;
+}