Hi, Q: is there a way to query the crypto layer whether a given algorithm (digest, crypto) is accelerated by the driver? This information can be used to decide if eg. a checksum should can be calculated right away or offloaded to a thread. This is done in btrfs, (fs/btrfs/disk-io.c:check_async_write). At this moment it contains a static check for a cpu feature, and only for x86. I briefly searched the arch/ directory for implementations of crc32c that possibly use hw aid and there are several of them. Adding a static check a-la x86 for the other architectures (arm, ppc, mips, sparc, s390) is wrong, so I'm looking for a clean solution. The struct shash_alg definition of the algorithms does not say anything about the acceleration. The closest thing is the cra_priority, but I don't know if this is reliable information. The default implementations seem to have 100, and acceleated 200 or 300. This would be probably sufficient, but I'd like a confirmation from crypto people. Thanks.
