This patch adds the skcipher walk interface which replaces both
blkcipher walk and ablkcipher walk. Just like blkcipher walk it
can also be used for AEAD algorithms.
Signed-off-by: Herbert Xu <[email protected]>
---
crypto/skcipher.c | 512 +++++++++++++++++++++++++++++++++++++
include/crypto/internal/skcipher.h | 47 +++
2 files changed, 559 insertions(+)
diff --git a/crypto/skcipher.c b/crypto/skcipher.c
index f7d0018..58173b6 100644
--- a/crypto/skcipher.c
+++ b/crypto/skcipher.c
@@ -14,9 +14,12 @@
*
*/
+#include <crypto/internal/aead.h>
#include <crypto/internal/skcipher.h>
+#include <crypto/scatterwalk.h>
#include <linux/bug.h>
#include <linux/cryptouser.h>
+#include <linux/list.h>
#include <linux/module.h>
#include <linux/rtnetlink.h>
#include <linux/seq_file.h>
@@ -24,6 +27,515 @@
#include "internal.h"
+enum {
+ SKCIPHER_WALK_PHYS = 1 << 0,
+ SKCIPHER_WALK_SLOW = 1 << 1,
+ SKCIPHER_WALK_COPY = 1 << 2,
+ SKCIPHER_WALK_DIFF = 1 << 3,
+ SKCIPHER_WALK_SLEEP = 1 << 4,
+};
+
+struct skcipher_walk_buffer {
+ struct list_head entry;
+ struct scatter_walk dst;
+ unsigned int len;
+ u8 *data;
+ u8 buffer[];
+};
+
+static int skcipher_walk_next(struct skcipher_walk *walk);
+
+static inline void skcipher_unmap(struct scatter_walk *walk, void *vaddr)
+{
+ if (PageHighMem(scatterwalk_page(walk)))
+ kunmap_atomic(vaddr);
+}
+
+static inline void *skcipher_map(struct scatter_walk *walk)
+{
+ struct page *page = scatterwalk_page(walk);
+
+ return (PageHighMem(page) ? kmap_atomic(page) : page_address(page)) +
+ offset_in_page(walk->offset);
+}
+
+static inline void skcipher_map_src(struct skcipher_walk *walk)
+{
+ walk->src.virt.addr = skcipher_map(&walk->in);
+}
+
+static inline void skcipher_map_dst(struct skcipher_walk *walk)
+{
+ walk->dst.virt.addr = skcipher_map(&walk->out);
+}
+
+static inline void skcipher_unmap_src(struct skcipher_walk *walk)
+{
+ skcipher_unmap(&walk->in, walk->src.virt.addr);
+}
+
+static inline void skcipher_unmap_dst(struct skcipher_walk *walk)
+{
+ skcipher_unmap(&walk->out, walk->dst.virt.addr);
+}
+
+static inline gfp_t skcipher_walk_gfp(struct skcipher_walk *walk)
+{
+ return walk->flags & SKCIPHER_WALK_SLEEP ? GFP_KERNEL : GFP_ATOMIC;
+}
+
+/* Get a spot of the specified length that does not straddle a page.
+ * The caller needs to ensure that there is enough space for this operation.
+ */
+static inline u8 *skcipher_get_spot(u8 *start, unsigned int len)
+{
+ u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
+
+ return max(start, end_page);
+}
+
+static int skcipher_done_slow(struct skcipher_walk *walk, unsigned int bsize)
+{
+ u8 *addr;
+
+ addr = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);
+ addr = skcipher_get_spot(addr, bsize);
+ scatterwalk_copychunks(addr, &walk->out, bsize,
+ (walk->flags & SKCIPHER_WALK_PHYS) ? 2 : 1);
+ return 0;
+}
+
+int skcipher_walk_done(struct skcipher_walk *walk, int err)
+{
+ unsigned int nbytes = 0;
+ unsigned int n = 0;
+
+ if (likely(err >= 0)) {
+ n = walk->nbytes - err;
+ nbytes = walk->total - n;
+ }
+
+ if (likely(!(walk->flags & (SKCIPHER_WALK_PHYS |
+ SKCIPHER_WALK_SLOW |
+ SKCIPHER_WALK_COPY |
+ SKCIPHER_WALK_DIFF)))) {
+unmap_src:
+ skcipher_unmap_src(walk);
+ } else if (walk->flags & SKCIPHER_WALK_DIFF) {
+ skcipher_unmap_dst(walk);
+ goto unmap_src;
+ } else if (walk->flags & SKCIPHER_WALK_COPY) {
+ skcipher_map_dst(walk);
+ memcpy(walk->dst.virt.addr, walk->page, n);
+ skcipher_unmap_dst(walk);
+ } else if (unlikely(walk->flags & SKCIPHER_WALK_SLOW)) {
+ if (!err)
+ n = skcipher_done_slow(walk, n);
+ else if (WARN_ON(err > 0)) {
+ err = -EINVAL;
+ nbytes = 0;
+ }
+ }
+
+ if (err >= 0)
+ err = 0;
+
+ walk->total = nbytes;
+ walk->nbytes = nbytes;
+
+ scatterwalk_advance(&walk->in, n);
+ scatterwalk_advance(&walk->out, n);
+ scatterwalk_done(&walk->in, 0, nbytes);
+ scatterwalk_done(&walk->out, 1, nbytes);
+
+ if (nbytes) {
+ crypto_yield(walk->flags & SKCIPHER_WALK_SLEEP ?
+ CRYPTO_TFM_REQ_MAY_SLEEP : 0);
+ return skcipher_walk_next(walk);
+ }
+
+ /* Short-circuit for the common/fast path. */
+ if (!(((unsigned long)walk->iv ^ (unsigned long)walk->oiv) |
+ ((unsigned long)walk->buffer ^ (unsigned long)walk->page) |
+ (unsigned long)walk->page))
+ goto out;
+
+ if (walk->flags & SKCIPHER_WALK_PHYS)
+ goto out;
+
+ if (walk->iv != walk->oiv)
+ memcpy(walk->oiv, walk->iv, walk->ivsize);
+ if (walk->buffer != walk->page)
+ kfree(walk->buffer);
+ if (walk->page)
+ free_page((unsigned long)walk->page);
+
+out:
+ return err;
+}
+EXPORT_SYMBOL_GPL(skcipher_walk_done);
+
+void skcipher_walk_complete(struct skcipher_walk *walk, int err)
+{
+ struct skcipher_walk_buffer *p, *tmp;
+
+ list_for_each_entry_safe(p, tmp, &walk->buffers, entry) {
+ u8 *data;
+
+ if (err)
+ goto done;
+
+ data = p->data;
+ if (!data) {
+ data = PTR_ALIGN(&p->buffer[0], walk->alignmask + 1);
+ data = skcipher_get_spot(data, walk->chunksize);
+ }
+
+ scatterwalk_copychunks(data, &p->dst, p->len, 1);
+
+ if (offset_in_page(p->data) + p->len + walk->chunksize >
+ PAGE_SIZE)
+ free_page((unsigned long)p->data);
+
+done:
+ list_del(&p->entry);
+ kfree(p);
+ }
+
+ if (!err && walk->iv != walk->oiv)
+ memcpy(walk->oiv, walk->iv, walk->ivsize);
+ if (walk->buffer != walk->page)
+ kfree(walk->buffer);
+ if (walk->page)
+ free_page((unsigned long)walk->page);
+}
+EXPORT_SYMBOL_GPL(skcipher_walk_complete);
+
+static void skcipher_queue_write(struct skcipher_walk *walk,
+ struct skcipher_walk_buffer *p)
+{
+ p->dst = walk->out;
+ list_add_tail(&p->entry, &walk->buffers);
+}
+
+static int skcipher_next_slow(struct skcipher_walk *walk)
+{
+ bool phys = walk->flags & SKCIPHER_WALK_PHYS;
+ unsigned alignmask = walk->alignmask;
+ unsigned bsize = walk->chunksize;
+ struct skcipher_walk_buffer *p;
+ unsigned a;
+ unsigned n;
+ u8 *buffer;
+ void *v;
+
+ if (!phys) {
+ buffer = walk->buffer ?: walk->page;
+ if (buffer)
+ goto ok;
+ }
+
+ /* Start with the minimum alignment of kmalloc. */
+ a = crypto_tfm_ctx_alignment() - 1;
+ n = bsize;
+
+ if (phys) {
+ /* Calculate the minimum alignment of p->buffer. */
+ a &= (sizeof(*p) ^ (sizeof(*p) - 1)) >> 1;
+ n += sizeof(*p);
+ }
+
+ /* Minimum size to align p->buffer by alignmask. */
+ n += alignmask & ~a;
+
+ /* Minimum size to ensure p->buffer does not straddle a page. */
+ n += (bsize - 1) & ~(alignmask | a);
+
+ v = kzalloc(n, skcipher_walk_gfp(walk));
+ if (!v)
+ return skcipher_walk_done(walk, -ENOMEM);
+
+ if (phys) {
+ p = v;
+ p->len = bsize;
+ skcipher_queue_write(walk, p);
+ buffer = p->buffer;
+ } else {
+ walk->buffer = v;
+ buffer = v;
+ }
+
+ok:
+ walk->dst.virt.addr = PTR_ALIGN(buffer, alignmask + 1);
+ walk->dst.virt.addr = skcipher_get_spot(walk->dst.virt.addr, bsize);
+ walk->src.virt.addr = walk->dst.virt.addr;
+
+ scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0);
+
+ walk->nbytes = bsize;
+ walk->flags |= SKCIPHER_WALK_SLOW;
+
+ return 0;
+}
+
+static int skcipher_next_copy(struct skcipher_walk *walk)
+{
+ struct skcipher_walk_buffer *p;
+ u8 *tmp = walk->page;
+
+ skcipher_map_src(walk);
+ memcpy(tmp, walk->src.virt.addr, walk->nbytes);
+ skcipher_unmap_src(walk);
+
+ walk->src.virt.addr = tmp;
+ walk->dst.virt.addr = tmp;
+
+ if (!(walk->flags & SKCIPHER_WALK_PHYS))
+ return 0;
+
+ p = kmalloc(sizeof(*p), skcipher_walk_gfp(walk));
+ if (!p)
+ return -ENOMEM;
+
+ p->data = walk->page;
+ p->len = walk->nbytes;
+ skcipher_queue_write(walk, p);
+
+ if (offset_in_page(walk->page) + walk->nbytes + walk->chunksize >
+ PAGE_SIZE)
+ walk->page = NULL;
+ else
+ walk->page += walk->nbytes;
+
+ return 0;
+}
+
+static int skcipher_next_fast(struct skcipher_walk *walk)
+{
+ unsigned long diff;
+
+ walk->src.phys.page = scatterwalk_page(&walk->in);
+ walk->src.phys.offset = offset_in_page(walk->in.offset);
+ walk->dst.phys.page = scatterwalk_page(&walk->out);
+ walk->dst.phys.offset = offset_in_page(walk->out.offset);
+
+ if (walk->flags & SKCIPHER_WALK_PHYS)
+ return 0;
+
+ diff = walk->src.phys.offset - walk->dst.phys.offset;
+ diff |= walk->src.virt.page - walk->dst.virt.page;
+
+ skcipher_map_src(walk);
+ walk->dst.virt.addr = walk->src.virt.addr;
+
+ if (diff) {
+ walk->flags |= SKCIPHER_WALK_DIFF;
+ skcipher_map_dst(walk);
+ }
+
+ return 0;
+}
+
+int skcipher_walk_next(struct skcipher_walk *walk)
+{
+ unsigned int bsize;
+ unsigned int n;
+ int err;
+
+ walk->flags &= ~(SKCIPHER_WALK_SLOW | SKCIPHER_WALK_COPY |
+ SKCIPHER_WALK_DIFF);
+
+ n = walk->total;
+ bsize = min(walk->chunksize, max(n, walk->blocksize));
+ n = scatterwalk_clamp(&walk->in, n);
+ n = scatterwalk_clamp(&walk->out, n);
+
+ if (unlikely(n < bsize)) {
+ if (unlikely(walk->total < walk->blocksize))
+ return skcipher_walk_done(walk, -EINVAL);
+
+slow_path:
+ err = skcipher_next_slow(walk);
+ goto set_phys_lowmem;
+ }
+
+ if (unlikely((walk->in.offset | walk->out.offset) & walk->alignmask)) {
+ if (!walk->page) {
+ gfp_t gfp = skcipher_walk_gfp(walk);
+
+ walk->page = (void *)__get_free_page(gfp);
+ if (!walk->page)
+ goto slow_path;
+ }
+
+ walk->nbytes = min_t(unsigned, n,
+ PAGE_SIZE - offset_in_page(walk->page));
+ walk->flags |= SKCIPHER_WALK_COPY;
+ err = skcipher_next_copy(walk);
+ goto set_phys_lowmem;
+ }
+
+ walk->nbytes = n;
+
+ return skcipher_next_fast(walk);
+
+set_phys_lowmem:
+ if (!err && (walk->flags & SKCIPHER_WALK_PHYS)) {
+ walk->src.phys.page = virt_to_page(walk->src.virt.addr);
+ walk->dst.phys.page = virt_to_page(walk->dst.virt.addr);
+ walk->src.phys.offset &= PAGE_SIZE - 1;
+ walk->dst.phys.offset &= PAGE_SIZE - 1;
+ }
+ return err;
+}
+EXPORT_SYMBOL_GPL(skcipher_walk_next);
+
+static int skcipher_copy_iv(struct skcipher_walk *walk)
+{
+ unsigned a = crypto_tfm_ctx_alignment() - 1;
+ unsigned alignmask = walk->alignmask;
+ unsigned ivsize = walk->ivsize;
+ unsigned bs = walk->chunksize;
+ unsigned aligned_bs;
+ unsigned size;
+ u8 *iv;
+
+ aligned_bs = ALIGN(bs, alignmask);
+
+ /* Minimum size to align buffer by alignmask. */
+ size = alignmask & ~a;
+
+ if (walk->flags & SKCIPHER_WALK_PHYS)
+ size += ivsize;
+ else {
+ size += aligned_bs + ivsize;
+
+ /* Minimum size to ensure buffer does not straddle a page. */
+ size += (bs - 1) & ~(alignmask | a);
+ }
+
+ walk->buffer = kmalloc(size, skcipher_walk_gfp(walk));
+ if (!walk->buffer)
+ return -ENOMEM;
+
+ iv = PTR_ALIGN(walk->buffer, alignmask + 1);
+ iv = skcipher_get_spot(iv, bs) + aligned_bs;
+
+ walk->iv = memcpy(iv, walk->iv, walk->ivsize);
+ return 0;
+}
+
+static int skcipher_walk_first(struct skcipher_walk *walk)
+{
+ if (WARN_ON_ONCE(in_irq()))
+ return -EDEADLK;
+
+ walk->nbytes = walk->total;
+ if (unlikely(!walk->total))
+ return 0;
+
+ walk->buffer = NULL;
+ if (unlikely(((unsigned long)walk->iv & walk->alignmask))) {
+ int err = skcipher_copy_iv(walk);
+ if (err)
+ return err;
+ }
+
+ walk->page = NULL;
+
+ return skcipher_walk_next(walk);
+}
+
+static int skcipher_walk_skcipher(struct skcipher_walk *walk,
+ struct skcipher_request *req)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+
+ scatterwalk_start(&walk->in, req->src);
+ scatterwalk_start(&walk->out, req->dst);
+
+ walk->in.sg = req->src;
+ walk->out.sg = req->dst;
+ walk->total = req->cryptlen;
+ walk->iv = req->iv;
+ walk->oiv = req->iv;
+
+ walk->flags |= req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ?
+ SKCIPHER_WALK_SLEEP : 0;
+
+ walk->blocksize = crypto_skcipher_blocksize(tfm);
+ walk->chunksize = crypto_skcipher_chunksize(tfm);
+ walk->ivsize = crypto_skcipher_ivsize(tfm);
+ walk->alignmask = crypto_skcipher_alignmask(tfm);
+
+ return skcipher_walk_first(walk);
+}
+
+int skcipher_walk_virt(struct skcipher_walk *walk,
+ struct skcipher_request *req, bool atomic)
+{
+ int err;
+
+ walk->flags &= ~SKCIPHER_WALK_PHYS;
+
+ err = skcipher_walk_skcipher(walk, req);
+
+ walk->flags &= atomic ? ~SKCIPHER_WALK_SLEEP : ~0;
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(skcipher_walk_virt);
+
+void skcipher_walk_atomise(struct skcipher_walk *walk)
+{
+ walk->flags &= ~SKCIPHER_WALK_SLEEP;
+}
+EXPORT_SYMBOL_GPL(skcipher_walk_atomise);
+
+int skcipher_walk_async(struct skcipher_walk *walk,
+ struct skcipher_request *req)
+{
+ walk->flags |= SKCIPHER_WALK_PHYS;
+
+ INIT_LIST_HEAD(&walk->buffers);
+
+ return skcipher_walk_skcipher(walk, req);
+}
+EXPORT_SYMBOL_GPL(skcipher_walk_async);
+
+int skcipher_walk_aead(struct skcipher_walk *walk, struct aead_request *req,
+ bool atomic)
+{
+ struct crypto_aead *tfm = crypto_aead_reqtfm(req);
+ int err;
+
+ scatterwalk_start(&walk->in, req->src);
+ scatterwalk_start(&walk->out, req->dst);
+
+ scatterwalk_copychunks(NULL, &walk->in, req->assoclen, 2);
+ scatterwalk_copychunks(NULL, &walk->out, req->assoclen, 2);
+
+ walk->total = req->cryptlen;
+ walk->iv = req->iv;
+ walk->oiv = req->iv;
+
+ if (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP)
+ walk->flags |= SKCIPHER_WALK_SLEEP;
+
+ walk->blocksize = crypto_aead_blocksize(tfm);
+ walk->chunksize = crypto_aead_chunksize(tfm);
+ walk->ivsize = crypto_aead_ivsize(tfm);
+ walk->alignmask = crypto_aead_alignmask(tfm);
+
+ err = skcipher_walk_first(walk);
+
+ if (atomic)
+ walk->flags &= ~SKCIPHER_WALK_SLEEP;
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(skcipher_walk_aead);
+
static unsigned int crypto_skcipher_extsize(struct crypto_alg *alg)
{
if (alg->cra_type == &crypto_blkcipher_type)
diff --git a/include/crypto/internal/skcipher.h b/include/crypto/internal/skcipher.h
index 7a7e815..d55041f 100644
--- a/include/crypto/internal/skcipher.h
+++ b/include/crypto/internal/skcipher.h
@@ -15,8 +15,10 @@
#include <crypto/algapi.h>
#include <crypto/skcipher.h>
+#include <linux/list.h>
#include <linux/types.h>
+struct aead_request;
struct rtattr;
struct skcipher_instance {
@@ -34,6 +36,40 @@ struct crypto_skcipher_spawn {
struct crypto_spawn base;
};
+struct skcipher_walk {
+ union {
+ struct {
+ struct page *page;
+ unsigned long offset;
+ } phys;
+
+ struct {
+ u8 *page;
+ void *addr;
+ } virt;
+ } src, dst;
+
+ struct scatter_walk in;
+ unsigned int nbytes;
+
+ struct scatter_walk out;
+ unsigned int total;
+
+ struct list_head buffers;
+
+ u8 *page;
+ u8 *buffer;
+ u8 *oiv;
+ void *iv;
+
+ unsigned int ivsize;
+
+ int flags;
+ unsigned int blocksize;
+ unsigned int chunksize;
+ unsigned int alignmask;
+};
+
extern const struct crypto_type crypto_givcipher_type;
static inline struct crypto_instance *skcipher_crypto_instance(
@@ -104,6 +140,17 @@ static inline void crypto_skcipher_set_reqsize(
int skcipher_register_instance(struct crypto_template *tmpl,
struct skcipher_instance *inst);
+int skcipher_walk_done(struct skcipher_walk *walk, int err);
+int skcipher_walk_virt(struct skcipher_walk *walk,
+ struct skcipher_request *req,
+ bool atomic);
+void skcipher_walk_atomise(struct skcipher_walk *walk);
+int skcipher_walk_async(struct skcipher_walk *walk,
+ struct skcipher_request *req);
+int skcipher_walk_aead(struct skcipher_walk *walk, struct aead_request *req,
+ bool atomic);
+void skcipher_walk_complete(struct skcipher_walk *walk, int err);
+
static inline void ablkcipher_request_complete(struct ablkcipher_request *req,
int err)
{
Hi Herbert, just a few preliminary comments. I haven't made it through
everything yet.
On Wed, Nov 02, 2016 at 07:19:02AM +0800, Herbert Xu wrote:
> +static int skcipher_walk_first(struct skcipher_walk *walk)
> +{
> + if (WARN_ON_ONCE(in_irq()))
> + return -EDEADLK;
> +
> + walk->nbytes = walk->total;
> + if (unlikely(!walk->total))
> + return 0;
> +
> + walk->buffer = NULL;
> + if (unlikely(((unsigned long)walk->iv & walk->alignmask))) {
> + int err = skcipher_copy_iv(walk);
> + if (err)
> + return err;
> + }
> +
> + walk->page = NULL;
> +
> + return skcipher_walk_next(walk);
> +}
I think the case where skcipher_copy_iv() fails may be handled incorrectly.
Wouldn't it need to set walk.nbytes to 0 so as to not confuse callers which
expect that behavior? Or maybe it should be calling skcipher_walk_done().
> +static int skcipher_walk_skcipher(struct skcipher_walk *walk,
> + struct skcipher_request *req)
> +{
> + struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
> +
> + scatterwalk_start(&walk->in, req->src);
> + scatterwalk_start(&walk->out, req->dst);
> +
> + walk->in.sg = req->src;
> + walk->out.sg = req->dst;
Setting walk->in.sg and walk->out.sg is redundant with the scatterwalk_start()
calls.
> +int skcipher_walk_virt(struct skcipher_walk *walk,
> + struct skcipher_request *req, bool atomic)
> +{
> + int err;
> +
> + walk->flags &= ~SKCIPHER_WALK_PHYS;
> +
> + err = skcipher_walk_skcipher(walk, req);
> +
> + walk->flags &= atomic ? ~SKCIPHER_WALK_SLEEP : ~0;
> +
> + return err;
> +}
This gets called with uninitialized 'walk.flags'. This was somewhat of a
theoretical problem with the old blkcipher_walk code but it looks like now it
will interact badly with the new SKCIPHER_WALK_SLEEP flag. As far as I can see,
whether the flag will end up set or not can depend on the uninitialized value.
It would be nice if this problem could be avoided entirely be setting flags=0.
I'm also wondering about the choice to not look at 'atomic' until after the call
to skcipher_walk_skcipher(). Wouldn't this mean that the choice of 'atomic'
would not be respected in e.g. the kmalloc() in skcipher_copy_iv()?
> +int skcipher_walk_async(struct skcipher_walk *walk,
> + struct skcipher_request *req)
> +{
> + walk->flags |= SKCIPHER_WALK_PHYS;
> +
> + INIT_LIST_HEAD(&walk->buffers);
> +
> + return skcipher_walk_skcipher(walk, req);
> +}
> +EXPORT_SYMBOL_GPL(skcipher_walk_async);
I don't see any users of the "async" walking being introduced; are some planned?
Eric
On Wed, Nov 02, 2016 at 01:54:20PM -0700, Eric Biggers wrote:
>
> I think the case where skcipher_copy_iv() fails may be handled incorrectly.
> Wouldn't it need to set walk.nbytes to 0 so as to not confuse callers which
> expect that behavior? Or maybe it should be calling skcipher_walk_done().
Good catch. I'll fix and repost.
> Setting walk->in.sg and walk->out.sg is redundant with the scatterwalk_start()
> calls.
Will remove.
> This gets called with uninitialized 'walk.flags'. This was somewhat of a
> theoretical problem with the old blkcipher_walk code but it looks like now it
> will interact badly with the new SKCIPHER_WALK_SLEEP flag. As far as I can see,
> whether the flag will end up set or not can depend on the uninitialized value.
> It would be nice if this problem could be avoided entirely be setting flags=0.
Right. I'll fix this as well.
> I'm also wondering about the choice to not look at 'atomic' until after the call
> to skcipher_walk_skcipher(). Wouldn't this mean that the choice of 'atomic'
> would not be respected in e.g. the kmalloc() in skcipher_copy_iv()?
The atomic flag is meant to be used in cases such as aesni where
you need to do kernel_fpu_begin after the call to start the walk.
IOW sleeping is fine at the start but not on subsequent walk calls.
> I don't see any users of the "async" walking being introduced; are some planned?
skcipher_walk is meant to unite blkcipher_walk and ablkcipher_walk.
The latter will use the async case.
Cheers,
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt