In skcipher_walk_done(), instead of calling crypto_yield() which
requires a translation between flags, just call cond_resched() directly.
This has the same effect.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

The helper functions like crypto_skcipher_blocksize() take in a pointer
to a tfm object, but they actually return properties of the algorithm.
As the Linux kernel is compiled with -fno-strict-aliasing, the compiler
has to assume that the writes to struct skcipher_walk could clobber the
tfm's pointer to its algorithm.  Thus it gets repeatedly reloaded in the
generated code.  Therefore, replace the use of these helper functions
with staightforward accesses to the struct fields.

Note that while *users* of the skcipher and aead APIs are supposed to
use the helper functions, this particular code is part of the API
*implementation* in crypto/skcipher.c, which already accesses the
algorithm struct directly in many cases.  So there is no reason to
prefer the helper functions here.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

- Initialize SKCIPHER_WALK_SLEEP in a consistent way, and check for
  atomic=true at the same time as CRYPTO_TFM_REQ_MAY_SLEEP.  Technically
  atomic=true only needs to apply after the first step, but it is very
  rarely used.  We should optimize for the common case.  So, check
  'atomic' alongside CRYPTO_TFM_REQ_MAY_SLEEP.  This is more efficient.

- Initialize flags other than SKCIPHER_WALK_SLEEP to 0 rather than
  preserving them.  No caller actually initializes the flags, which
  makes it impossible to use their original values for anything.
  Indeed, that does not happen and all meaningful flags get overridden
  anyway.  It may have been thought that just clearing one flag would be
  faster than clearing all flags, but that's not the case as the former
  is a read-write operation whereas the latter is just a write.

- Move the explicit clearing of SKCIPHER_WALK_SLOW, SKCIPHER_WALK_COPY,
  and SKCIPHER_WALK_DIFF into skcipher_walk_done(), since it is now
  only needed on non-first steps.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Fold skcipher_walk_skcipher() into skcipher_walk_virt() which is its
only remaining caller.  No change in behavior.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

In skcipher_walk_done(), remove the check for SKCIPHER_WALK_SLOW because
it is always true.  All other flags (and lack thereof) were checked
earlier in the function, leaving SKCIPHER_WALK_SLOW as the only
remaining possibility.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

In the case where skcipher_walk_next() allocates a bounce page, that
page by definition has size PAGE_SIZE.  The number of bytes to copy 'n'
is guaranteed to fit in it, since earlier in the function it was clamped
to be at most a page.  Therefore remove the unnecessary logic that tried
to clamp 'n' again to fit in the bounce page.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

In the slow path of skcipher_walk where it uses a slab bounce buffer for
the data and/or IV, do not bother to avoid crossing a page boundary in
the part(s) of this buffer that are used, and do not bother to allocate
extra space in the buffer for that purpose.  The buffer is accessed only
by virtual address, so pages are irrelevant for it.

This logic may have been present due to the physical address support in
skcipher_walk, but that has now been removed.  Or it may have been
present to be consistent with the fast path that currently does not hand
back addresses that span pages, but that behavior is a side effect of
the pages being "mapped" one by one and is not actually a requirement.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

skcipher_walk_done() has an unusual calling convention, and some of its
local variables have unclear names.  Document it and rename variables to
make it a bit clearer what is going on.  No change in behavior.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Since the physical address support in skcipher_walk is not used anymore,
remove all the code associated with it.  This includes:

- The skcipher_walk_async() and skcipher_walk_complete() functions;

- The SKCIPHER_WALK_PHYS flag and everything conditional on it;

- The buffers, phys, and virt.page fields in struct skcipher_walk;

- struct skcipher_walk_buffer.

As a result, skcipher_walk now just supports virtual addresses.
Physical address support in skcipher_walk is unneeded because drivers
that need physical addresses just use the scatterlists directly.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Clean up the existing export namespace code along the same lines of
commit 33def8498fdd ("treewide: Convert macro and uses of __section(foo)
to __section("foo")") and for the same reason, it is not desired for the
namespace argument to be a macro expansion itself.

Scripted using

  git grep -l -e MODULE_IMPORT_NS -e EXPORT_SYMBOL_NS | while read file;
  do
    awk -i inplace '
      /^#define EXPORT_SYMBOL_NS/ {
        gsub(/__stringify\(ns\)/, "ns");
        print;
        next;
      }
      /^#define MODULE_IMPORT_NS/ {
        gsub(/__stringify\(ns\)/, "ns");
        print;
        next;
      }
      /MODULE_IMPORT_NS/ {
        $0 = gensub(/MODULE_IMPORT_NS\(([^)]*)\)/, "MODULE_IMPORT_NS(\"\\1\")", "g");
      }
      /EXPORT_SYMBOL_NS/ {
        if ($0 ~ /(EXPORT_SYMBOL_NS[^(]*)\(([^,]+),/) {
  	if ($0 !~ /(EXPORT_SYMBOL_NS[^(]*)\(([^,]+), ([^)]+)\)/ &&
  	    $0 !~ /(EXPORT_SYMBOL_NS[^(]*)\(\)/ &&
  	    $0 !~ /^my/) {
  	  getline line;
  	  gsub(/[[:space:]]*\\$/, "");
  	  gsub(/[[:space:]]/, "", line);
  	  $0 = $0 " " line;
  	}

  	$0 = gensub(/(EXPORT_SYMBOL_NS[^(]*)\(([^,]+), ([^)]+)\)/,
  		    "\\1(\\2, \"\\3\")", "g");
        }
      }
      { print }' $file;
  done

Requested-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://mail.google.com/mail/u/2/#inbox/FMfcgzQXKWgMmjdFwwdsfgxzKpVHWPlc
Acked-by: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>