zfs: merge openzfs/zfs@17b2ae0b2 (master) into main

Notable upstream pull request merges:
#12766 Fix error propagation from lzc_send_redacted
#12805 Updated the lz4 decompressor
#12851 FreeBSD: Provide correct file generation number
#12857 Verify dRAID empty sectors
#12874 FreeBSD: Update argument types for VOP_READDIR
#12896 Reduce number of arc_prune threads
#12934 FreeBSD: Fix zvol_*_open() locking
#12947 lz4: Cherrypick fix for CVE-2021-3520
#12961 FreeBSD: Fix leaked strings in libspl mnttab
#12964 Fix handling of errors from dmu_write_uio_dbuf() on FreeBSD
#12981 Introduce a flag to skip comparing the local mac when raw sending
#12985 Avoid memory allocations in the ARC eviction thread

Obtained from: OpenZFS
OpenZFS commit: 17b2ae0b24d487fdda2ef1098ec26fa7f79a61f6

zfs: lz4: add optional kmem_alloc support

lz4 port from illumos to Linux added a 16KB per-CPU cache to accommodate for
the missing 16KB malloc. FreeBSD supports this size, making the extra cache
harmful as it can't share buckets.

Initial import from vendor-sys branch of openzfs

zfs: lz4: add optional kmem_alloc support

lz4 port from illumos to Linux added a 16KB per-CPU cache to accommodate for
the missing 16KB malloc. FreeBSD supports this size, making the extra cache
harmful as it can't share buckets.