Updating code based on PR code comments. I adjusted the following parts
of code based on comments:
1. Revert dbuf_undirty() to original logic and got rid of uncessary
code change.
2. Cleanup in abd_impl.h
3. Cleanup in abd.h
4. Got rid of duplicate declaration of dmu_buf_hold_noread() in dmu.h.
5. Cleaned up comment for db_mtx in dmu_imp.h
6. Updated zfsprop man page to state correct ZFS version
7. Updated to correct cast in zfs_uio_page_aligned() calls to use
uintptr_t.
8. Cleaned up comment in FreeBSD uio code.
9. Removed unnecessary format changes in comments in Linux abd code.
10. Updated ZFS VFS hook for direct_IO to use PANIC().
11. Updated comment above dbuf_undirty to use double space again.
12. Converted module paramter zfs_vdev_direct_write_verify_pct OS
indedepent and in doing so this removed the uneccessary check for
bounds.
13. Updated to casting in zfs_dio_page_aligned to uniptr_t and added
kernel guard.
14. Updated zfs_dio_size_aligned() to use modulo math because
dn->dn_datablksz is not required to be a power of 2.
15. Removed abd scatter stats update calls from all
ABD_FLAG_FROM_PAGES.
16. Updated check in abd_alloc_from_pages() for the linear page. This
way a single page that is even 4K can represented as an
ABD_FLAG_LINEAR_PAGE.
17. Fixing types for UIO code. In FreeBSD the vm code expects and
returns int's for values. In linux the interfaces return long value
in get_user_pages_unlocked() and rest of the IOV interfaces return
int's. Stuck with the worse case and used long for npages in Linux.
Updated the uio npage struct to correspond to the correct types and
that type checking is consistent in the UIO code.
18. Updated comments about what zfs_uio_get_pages_alloc() is doing.
19. Updated error handeling in zfs_uio_get_dio_pages_alloc() for Linux.
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
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