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Currently, the shash API checks the alignment of all message, key, and digest buffers against the algorithm's declared alignmask, and for any unaligned buffers it falls back to manually aligned temporary buffers. This is virtually useless, however. In the case of the message buffer, cryptographic hash functions internally operate on fixed-size blocks, so implementations end up needing to deal with byte-aligned data anyway because the length(s) passed to ->update might not be divisible by the block size. Word-alignment of the message can theoretically be helpful for CRCs, like what was being done in crc32c-sparc64. But in practice it's better for the algorithms to use unaligned accesses or align the message themselves. A similar argument applies to the key and digest. In any case, no shash algorithms actually set a nonzero alignmask anymore. Therefore, remove support for it from shash. The benefit is that all the code to handle "misaligned" buffers in the shash API goes away, reducing the overhead of the shash API. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.