mirror_zfs/lib/libspl/include/sys
Brian Behlendorf 1c2358c12a
Linux 5.10 compat: use iov_iter in uio structure
As of the 5.10 kernel the generic splice compatibility code has been
removed.  All filesystems are now responsible for registering a
->splice_read and ->splice_write callback to support this operation.

The good news is the VFS provided generic_file_splice_read() and
iter_file_splice_write() callbacks can be used provided the ->iter_read
and ->iter_write callback support pipes.  However, this is currently
not the case and only iovecs and bvecs (not pipes) are ever attached
to the uio structure.

This commit changes that by allowing full iov_iter structures to be
attached to uios.  Ever since the 4.9 kernel the iov_iter structure
has supported iovecs, kvecs, bvevs, and pipes so it's desirable to
pass the entire thing when possible.  In conjunction with this the
uio helper functions (i.e uiomove(), uiocopy(), etc) have been
updated to understand the new UIO_ITER type.

Note that using the kernel provided uio_iter interfaces allowed the
existing Linux specific uio handling code to be simplified.  When
there's no longer a need to support kernel's older than 4.9, then
it will be possible to remove the iovec and bvec members from the
uio structure and always use a uio_iter.  Until then we need to
maintain all of the existing types for older kernels.

Some additional refactoring and cleanup was included in this change:

- Added checks to configure to detect available iov_iter interfaces.
  Some are available all the way back to the 3.10 kernel and are used
  when available.  In particular, uio_prefaultpages() now always uses
  iov_iter_fault_in_readable() which is available for all supported
  kernels.

- The unused UIO_USERISPACE type has been removed.  It is no longer
  needed now that the uio_seg enum is platform specific.

- Moved zfs_uio.c from the zcommon.ko module to the Linux specific
  platform code for the zfs.ko module.  This gets it out of libzfs
  where it was never needed and keeps this Linux specific code out
  of the common sources.

- Removed unnecessary O_APPEND handling from zfs_iter_write(), this
  is redundant and O_APPEND is already handled in zfs_write();

Reviewed-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #11351
2020-12-18 08:48:26 -08:00
..
dktp Drop unnecessary srcdir paths 2020-06-24 18:20:18 -07:00
acl_impl.h Add linux libspl support 2010-08-31 13:41:59 -07:00
acl.h Cross-platform acltype 2020-10-13 21:25:48 -07:00
callb.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
cmn_err.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
cred.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
debug.h Replace ASSERTV macro with compiler annotation 2019-12-05 12:37:00 -08:00
dkio.h Remove unnecessary references to slavery 2020-06-10 17:07:59 -07:00
dklabel.h Fix spelling 2017-01-03 11:31:18 -06:00
feature_tests.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
int_limits.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
int_types.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
inttypes.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
isa_defs.h Changes to make openzfs build within FreeBSD buildworld 2020-07-31 21:30:31 -07:00
kmem.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
kstat.h Fix typos in lib/ 2019-09-02 17:53:27 -07:00
list_impl.h change libspl list member names to match kernel 2020-04-23 15:53:14 -07:00
list.h Add linux libspl support 2010-08-31 13:41:59 -07:00
Makefile.am Drop unnecessary srcdir paths 2020-06-24 18:20:18 -07:00
mhd.h Add linux libspl support 2010-08-31 13:41:59 -07:00
mkdev.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
policy.h Illumos 3897 - zfs filesystem and snapshot limits 2015-04-28 16:22:51 -07:00
poll.h Fix header inclusions for standards conformance 2017-04-12 08:58:09 -07:00
priv.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
processor.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
sha2.h Move sha2.h to platform code 2019-10-31 15:45:58 -07:00
simd.h FreeBSD: Fixes required to build ZFS on PowerPC 2020-07-25 11:00:23 -07:00
stack.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
stdtypes.h Update build system and packaging 2018-05-29 16:00:33 -07:00
strings.h Update build system and packaging 2018-05-29 16:00:33 -07:00
stropts.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
sunddi.h Add linux libspl support 2010-08-31 13:41:59 -07:00
systeminfo.h Add libtpool (thread pools) 2017-08-09 15:31:08 -07:00
time.h Linux 5.6 compat: time_t 2020-02-27 09:31:02 -08:00
trace_spl.h Enable use of DTRACE_PROBE* macros in "spl" module 2019-11-01 13:13:43 -07:00
trace_zfs.h Enable use of DTRACE_PROBE* macros in "spl" module 2019-11-01 13:13:43 -07:00
types32.h Update build system and packaging 2018-05-29 16:00:33 -07:00
types.h Update build system and packaging 2018-05-29 16:00:33 -07:00
tzfile.h Add linux libspl support 2010-08-31 13:41:59 -07:00
uio.h Linux 5.10 compat: use iov_iter in uio structure 2020-12-18 08:48:26 -08:00
va_list.h Replace __va_list with va_list 2014-08-13 10:35:00 -07:00
varargs.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
vnode.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
vtoc.h Fix typos in lib/ 2019-09-02 17:53:27 -07:00
zone.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00