3 files changed, 161 insertions, 95 deletions

diff --git a/crypto/cipher.c b/crypto/cipher.c
index 69264497b48c..c4243345b154 100644
--- a/crypto/cipher.c
+++ b/crypto/cipher.c
@@ -4,6 +4,7 @@
  * Cipher operations.
  *
  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
  *
  * 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
@@ -22,9 +23,13 @@
 #include "internal.h"
 #include "scatterwalk.h"
 
-typedef void (cryptfn_t)(void *, u8 *, const u8 *);
-typedef void (procfn_t)(struct crypto_tfm *, u8 *,
-                        u8*, cryptfn_t, void *);
+struct cipher_desc {
+        struct crypto_tfm *tfm;
+        void (*crfn)(void *ctx, u8 *dst, const u8 *src);
+        unsigned int (*prfn)(const struct cipher_desc *desc, u8 *dst,
+                             const u8 *src, unsigned int nbytes);
+        void *info;
+};
 
 static inline void xor_64(u8 *a, const u8 *b)
 {
@@ -39,63 +44,57 @@ static inline void xor_128(u8 *a, const u8 *b)
         ((u32 *)a)[2] ^= ((u32 *)b)[2];
         ((u32 *)a)[3] ^= ((u32 *)b)[3];
 }
- 
-static inline void *prepare_src(struct scatter_walk *walk, int bsize,
-                                void *tmp, int in_place)
+
+static unsigned int crypt_slow(const struct cipher_desc *desc,
+                               struct scatter_walk *in,
+                               struct scatter_walk *out, unsigned int bsize)
 {
-        void *src = walk->data;
-        int n = bsize;
+        u8 src[bsize];
+        u8 dst[bsize];
+        unsigned int n;
 
-        if (unlikely(scatterwalk_across_pages(walk, bsize))) {
-                src = tmp;
-                n = scatterwalk_copychunks(src, walk, bsize, 0);
-        }
-        scatterwalk_advance(walk, n);
-        return src;
-}
+        n = scatterwalk_copychunks(src, in, bsize, 0);
+        scatterwalk_advance(in, n);
 
-static inline void *prepare_dst(struct scatter_walk *walk, int bsize,
-                                void *tmp, int in_place)
-{
-        void *dst = walk->data;
+        desc->prfn(desc, dst, src, bsize);
 
-        if (unlikely(scatterwalk_across_pages(walk, bsize)) || in_place)
-                dst = tmp;
-        return dst;
-}
+        n = scatterwalk_copychunks(dst, out, bsize, 1);
+        scatterwalk_advance(out, n);
 
-static inline void complete_src(struct scatter_walk *walk, int bsize,
-                                void *src, int in_place)
-{
+        return bsize;
 }
 
-static inline void complete_dst(struct scatter_walk *walk, int bsize,
-                                void *dst, int in_place)
+static inline unsigned int crypt_fast(const struct cipher_desc *desc,
+                                      struct scatter_walk *in,
+                                      struct scatter_walk *out,
+                                      unsigned int nbytes)
 {
-        int n = bsize;
+        u8 *src, *dst;
+
+        src = in->data;
+        dst = scatterwalk_samebuf(in, out) ? src : out->data;
+
+        nbytes = desc->prfn(desc, dst, src, nbytes);
+
+        scatterwalk_advance(in, nbytes);
+        scatterwalk_advance(out, nbytes);
 
-        if (unlikely(scatterwalk_across_pages(walk, bsize)))
-                n = scatterwalk_copychunks(dst, walk, bsize, 1);
-        else if (in_place)
-                memcpy(walk->data, dst, bsize);
-        scatterwalk_advance(walk, n);
+        return nbytes;
 }
 
 /* 
  * Generic encrypt/decrypt wrapper for ciphers, handles operations across
  * multiple page boundaries by using temporary blocks.  In user context,
- * the kernel is given a chance to schedule us once per block.
+ * the kernel is given a chance to schedule us once per page.
  */
-static int crypt(struct crypto_tfm *tfm,
+static int crypt(const struct cipher_desc *desc,
                  struct scatterlist *dst,
                  struct scatterlist *src,
-                 unsigned int nbytes, cryptfn_t crfn,
-                 procfn_t prfn, void *info)
+                 unsigned int nbytes)
 {
         struct scatter_walk walk_in, walk_out;
+        struct crypto_tfm *tfm = desc->tfm;
         const unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
-        u8 tmp_src[bsize];
-        u8 tmp_dst[bsize];
 
         if (!nbytes)
                 return 0;
@@ -109,29 +108,20 @@ static int crypt(struct crypto_tfm *tfm,
         scatterwalk_start(&walk_out, dst);
 
         for(;;) {
-                u8 *src_p, *dst_p;
-                int in_place;
+                unsigned int n;
 
                 scatterwalk_map(&walk_in, 0);
                 scatterwalk_map(&walk_out, 1);
 
-                in_place = scatterwalk_samebuf(&walk_in, &walk_out);
+                n = scatterwalk_clamp(&walk_in, nbytes);
+                n = scatterwalk_clamp(&walk_out, n);
 
-                do {
-                        src_p = prepare_src(&walk_in, bsize, tmp_src,
-                                            in_place);
-                        dst_p = prepare_dst(&walk_out, bsize, tmp_dst,
-                                            in_place);
+                if (likely(n >= bsize))
+                        n = crypt_fast(desc, &walk_in, &walk_out, n);
+                else
+                        n = crypt_slow(desc, &walk_in, &walk_out, bsize);
 
-                        prfn(tfm, dst_p, src_p, crfn, info);
-
-                        complete_src(&walk_in, bsize, src_p, in_place);
-                        complete_dst(&walk_out, bsize, dst_p, in_place);
-
-                        nbytes -= bsize;
-                } while (nbytes &&
-                         !scatterwalk_across_pages(&walk_in, bsize) &&
-                         !scatterwalk_across_pages(&walk_out, bsize));
+                nbytes -= n;
 
                 scatterwalk_done(&walk_in, 0, nbytes);
                 scatterwalk_done(&walk_out, 1, nbytes);
@@ -143,30 +133,78 @@ static int crypt(struct crypto_tfm *tfm,
         }
 }
 
-static void cbc_process_encrypt(struct crypto_tfm *tfm, u8 *dst, u8 *src,
-                                cryptfn_t fn, void *info)
+static unsigned int cbc_process_encrypt(const struct cipher_desc *desc,
+                                        u8 *dst, const u8 *src,
+                                        unsigned int nbytes)
 {
-        u8 *iv = info;
+        struct crypto_tfm *tfm = desc->tfm;
+        void (*xor)(u8 *, const u8 *) = tfm->crt_u.cipher.cit_xor_block;
+        int bsize = crypto_tfm_alg_blocksize(tfm);
+
+        void (*fn)(void *, u8 *, const u8 *) = desc->crfn;
+        u8 *iv = desc->info;
+        unsigned int done = 0;
+
+        do {
+                xor(iv, src);
+                fn(crypto_tfm_ctx(tfm), dst, iv);
+                memcpy(iv, dst, bsize);
 
-        tfm->crt_u.cipher.cit_xor_block(iv, src);
-        fn(crypto_tfm_ctx(tfm), dst, iv);
-        memcpy(iv, dst, crypto_tfm_alg_blocksize(tfm));
+                src += bsize;
+                dst += bsize;
+        } while ((done += bsize) < nbytes);
+
+        return done;
 }
 
-static void cbc_process_decrypt(struct crypto_tfm *tfm, u8 *dst, u8 *src,
-                                cryptfn_t fn, void *info)
+static unsigned int cbc_process_decrypt(const struct cipher_desc *desc,
+                                        u8 *dst, const u8 *src,
+                                        unsigned int nbytes)
 {
-        u8 *iv = info;
+        struct crypto_tfm *tfm = desc->tfm;
+        void (*xor)(u8 *, const u8 *) = tfm->crt_u.cipher.cit_xor_block;
+        int bsize = crypto_tfm_alg_blocksize(tfm);
+
+        u8 stack[src == dst ? bsize : 0];
+        u8 *buf = stack;
+        u8 **dst_p = src == dst ? &buf : &dst;
+
+        void (*fn)(void *, u8 *, const u8 *) = desc->crfn;
+        u8 *iv = desc->info;
+        unsigned int done = 0;
+
+        do {
+                u8 *tmp_dst = *dst_p;
 
-        fn(crypto_tfm_ctx(tfm), dst, src);
-        tfm->crt_u.cipher.cit_xor_block(dst, iv);
-        memcpy(iv, src, crypto_tfm_alg_blocksize(tfm));
+                fn(crypto_tfm_ctx(tfm), tmp_dst, src);
+                xor(tmp_dst, iv);
+                memcpy(iv, src, bsize);
+                if (tmp_dst != dst)
+                        memcpy(dst, tmp_dst, bsize);
+
+                src += bsize;
+                dst += bsize;
+        } while ((done += bsize) < nbytes);
+
+        return done;
 }
 
-static void ecb_process(struct crypto_tfm *tfm, u8 *dst, u8 *src,
-                        cryptfn_t fn, void *info)
+static unsigned int ecb_process(const struct cipher_desc *desc, u8 *dst,
+                                const u8 *src, unsigned int nbytes)
 {
-        fn(crypto_tfm_ctx(tfm), dst, src);
+        struct crypto_tfm *tfm = desc->tfm;
+        int bsize = crypto_tfm_alg_blocksize(tfm);
+        void (*fn)(void *, u8 *, const u8 *) = desc->crfn;
+        unsigned int done = 0;
+
+        do {
+                fn(crypto_tfm_ctx(tfm), dst, src);
+
+                src += bsize;
+                dst += bsize;
+        } while ((done += bsize) < nbytes);
+
+        return done;
 }
 
 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
@@ -185,9 +223,13 @@ static int ecb_encrypt(struct crypto_tfm *tfm,
                        struct scatterlist *dst,
                        struct scatterlist *src, unsigned int nbytes)
 {
-        return crypt(tfm, dst, src, nbytes,
-                     tfm->__crt_alg->cra_cipher.cia_encrypt,
-                     ecb_process, NULL);
+        struct cipher_desc desc;
+
+        desc.tfm = tfm;
+        desc.crfn = tfm->__crt_alg->cra_cipher.cia_encrypt;
+        desc.prfn = ecb_process;
+
+        return crypt(&desc, dst, src, nbytes);
 }
 
 static int ecb_decrypt(struct crypto_tfm *tfm,
@@ -195,9 +237,13 @@ static int ecb_decrypt(struct crypto_tfm *tfm,
                        struct scatterlist *src,
                        unsigned int nbytes)
 {
-        return crypt(tfm, dst, src, nbytes,
-                     tfm->__crt_alg->cra_cipher.cia_decrypt,
-                     ecb_process, NULL);
+        struct cipher_desc desc;
+
+        desc.tfm = tfm;
+        desc.crfn = tfm->__crt_alg->cra_cipher.cia_decrypt;
+        desc.prfn = ecb_process;
+
+        return crypt(&desc, dst, src, nbytes);
 }
 
 static int cbc_encrypt(struct crypto_tfm *tfm,
@@ -205,9 +251,14 @@ static int cbc_encrypt(struct crypto_tfm *tfm,
                        struct scatterlist *src,
                        unsigned int nbytes)
 {
-        return crypt(tfm, dst, src, nbytes,
-                     tfm->__crt_alg->cra_cipher.cia_encrypt,
-                     cbc_process_encrypt, tfm->crt_cipher.cit_iv);
+        struct cipher_desc desc;
+
+        desc.tfm = tfm;
+        desc.crfn = tfm->__crt_alg->cra_cipher.cia_encrypt;
+        desc.prfn = cbc_process_encrypt;
+        desc.info = tfm->crt_cipher.cit_iv;
+
+        return crypt(&desc, dst, src, nbytes);
 }
 
 static int cbc_encrypt_iv(struct crypto_tfm *tfm,
@@ -215,9 +266,14 @@ static int cbc_encrypt_iv(struct crypto_tfm *tfm,
                           struct scatterlist *src,
                           unsigned int nbytes, u8 *iv)
 {
-        return crypt(tfm, dst, src, nbytes,
-                     tfm->__crt_alg->cra_cipher.cia_encrypt,
-                     cbc_process_encrypt, iv);
+        struct cipher_desc desc;
+
+        desc.tfm = tfm;
+        desc.crfn = tfm->__crt_alg->cra_cipher.cia_encrypt;
+        desc.prfn = cbc_process_encrypt;
+        desc.info = iv;
+
+        return crypt(&desc, dst, src, nbytes);
 }
 
 static int cbc_decrypt(struct crypto_tfm *tfm,
@@ -225,9 +281,14 @@ static int cbc_decrypt(struct crypto_tfm *tfm,
                        struct scatterlist *src,
                        unsigned int nbytes)
 {
-        return crypt(tfm, dst, src, nbytes,
-                     tfm->__crt_alg->cra_cipher.cia_decrypt,
-                     cbc_process_decrypt, tfm->crt_cipher.cit_iv);
+        struct cipher_desc desc;
+
+        desc.tfm = tfm;
+        desc.crfn = tfm->__crt_alg->cra_cipher.cia_decrypt;
+        desc.prfn = cbc_process_decrypt;
+        desc.info = tfm->crt_cipher.cit_iv;
+
+        return crypt(&desc, dst, src, nbytes);
 }
 
 static int cbc_decrypt_iv(struct crypto_tfm *tfm,
@@ -235,9 +296,14 @@ static int cbc_decrypt_iv(struct crypto_tfm *tfm,
                           struct scatterlist *src,
                           unsigned int nbytes, u8 *iv)
 {
-        return crypt(tfm, dst, src, nbytes,
-                     tfm->__crt_alg->cra_cipher.cia_decrypt,
-                     cbc_process_decrypt, iv);
+        struct cipher_desc desc;
+
+        desc.tfm = tfm;
+        desc.crfn = tfm->__crt_alg->cra_cipher.cia_decrypt;
+        desc.prfn = cbc_process_decrypt;
+        desc.info = iv;
+
+        return crypt(&desc, dst, src, nbytes);
 }
 
 static int nocrypt(struct crypto_tfm *tfm,
diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
index 50c9461e8cc6..47ac90e615f4 100644
--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -100,7 +100,7 @@ void scatterwalk_done(struct scatter_walk *walk, int out, int more)
 int scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
                            size_t nbytes, int out)
 {
-        do {
+        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;
@@ -108,7 +108,7 @@ int scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
                 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;
diff --git a/crypto/scatterwalk.h b/crypto/scatterwalk.h
index 02aa56c649b4..5495bb970816 100644
--- a/crypto/scatterwalk.h
+++ b/crypto/scatterwalk.h
@@ -40,10 +40,10 @@ static inline int scatterwalk_samebuf(struct scatter_walk *walk_in,
                walk_in->offset == walk_out->offset;
 }
 
-static inline int scatterwalk_across_pages(struct scatter_walk *walk,
-                                           unsigned int nbytes)
+static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
+                                             unsigned int nbytes)
 {
-        return nbytes > walk->len_this_page;
+        return nbytes > walk->len_this_page ? walk->len_this_page : nbytes;
 }
 
 static inline void scatterwalk_advance(struct scatter_walk *walk,