patch-2.4.26 linux-2.4.26/crypto/scatterwalk.c
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- Lines: 125
- Date:
2004-04-14 06:05:28.000000000 -0700
- Orig file:
linux-2.4.25/crypto/scatterwalk.c
- Orig date:
1969-12-31 16:00:00.000000000 -0800
diff -urN linux-2.4.25/crypto/scatterwalk.c linux-2.4.26/crypto/scatterwalk.c
@@ -0,0 +1,124 @@
+/*
+ * 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/scatterlist.h>
+#include "internal.h"
+#include "scatterwalk.h"
+
+enum km_type crypto_km_types[] = {
+ KM_USER0,
+ KM_USER1,
+ KM_SOFTIRQ0,
+ KM_SOFTIRQ1,
+};
+
+void *scatterwalk_whichbuf(struct scatter_walk *walk, unsigned int nbytes, void *scratch)
+{
+ if (nbytes <= walk->len_this_page &&
+ (((unsigned long)walk->data) & (PAGE_CACHE_SIZE - 1)) + nbytes <=
+ PAGE_CACHE_SIZE)
+ return walk->data;
+ else
+ return scratch;
+}
+
+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;
+
+ 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 void scatterwalk_pagedone(struct scatter_walk *walk, int out,
+ unsigned int more)
+{
+ /* 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 virutual address in the mapped page. */
+
+ 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)
+{
+ crypto_kunmap(walk->data, 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)
+{
+ if (buf != walk->data) {
+ while (nbytes > walk->len_this_page) {
+ memcpy_dir(buf, walk->data, walk->len_this_page, out);
+ buf += walk->len_this_page;
+ nbytes -= walk->len_this_page;
+
+ crypto_kunmap(walk->data, out);
+ scatterwalk_pagedone(walk, out, 1);
+ scatterwalk_map(walk, out);
+ }
+
+ memcpy_dir(buf, walk->data, nbytes, out);
+ }
+
+ walk->offset += nbytes;
+ walk->len_this_page -= nbytes;
+ walk->len_this_segment -= nbytes;
+ return 0;
+}
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