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1c2358c12a
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
167 lines
4.3 KiB
C
167 lines
4.3 KiB
C
/*
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* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
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* Copyright (C) 2007 The Regents of the University of California.
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* Copyright (c) 2015 by Chunwei Chen. All rights reserved.
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* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
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* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
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* UCRL-CODE-235197
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*
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* This file is part of the SPL, Solaris Porting Layer.
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*
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* The SPL is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* The SPL is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with the SPL. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef _SPL_UIO_H
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#define _SPL_UIO_H
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#include <sys/debug.h>
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#include <linux/uio.h>
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#include <linux/blkdev.h>
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#include <linux/blkdev_compat.h>
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#include <linux/mm.h>
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#include <linux/bio.h>
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#include <asm/uaccess.h>
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#include <sys/types.h>
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typedef struct iovec iovec_t;
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typedef enum uio_rw {
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UIO_READ = 0,
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UIO_WRITE = 1,
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} uio_rw_t;
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typedef enum uio_seg {
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UIO_USERSPACE = 0,
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UIO_SYSSPACE = 1,
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UIO_BVEC = 2,
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#if defined(HAVE_VFS_IOV_ITER)
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UIO_ITER = 3,
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#endif
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} uio_seg_t;
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typedef struct uio {
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union {
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const struct iovec *uio_iov;
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const struct bio_vec *uio_bvec;
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#if defined(HAVE_VFS_IOV_ITER)
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struct iov_iter *uio_iter;
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#endif
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};
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int uio_iovcnt;
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offset_t uio_loffset;
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uio_seg_t uio_segflg;
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boolean_t uio_fault_disable;
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uint16_t uio_fmode;
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uint16_t uio_extflg;
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ssize_t uio_resid;
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size_t uio_skip;
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} uio_t;
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#define uio_segflg(uio) (uio)->uio_segflg
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#define uio_offset(uio) (uio)->uio_loffset
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#define uio_resid(uio) (uio)->uio_resid
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#define uio_iovcnt(uio) (uio)->uio_iovcnt
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#define uio_iovlen(uio, idx) (uio)->uio_iov[(idx)].iov_len
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#define uio_iovbase(uio, idx) (uio)->uio_iov[(idx)].iov_base
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#define uio_fault_disable(uio, set) (uio)->uio_fault_disable = set
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static inline void
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uio_iov_at_index(uio_t *uio, uint_t idx, void **base, uint64_t *len)
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{
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*base = uio_iovbase(uio, idx);
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*len = uio_iovlen(uio, idx);
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}
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static inline void
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uio_advance(uio_t *uio, size_t size)
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{
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uio->uio_resid -= size;
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uio->uio_loffset += size;
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}
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static inline offset_t
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uio_index_at_offset(uio_t *uio, offset_t off, uint_t *vec_idx)
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{
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*vec_idx = 0;
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while (*vec_idx < uio_iovcnt(uio) && off >= uio_iovlen(uio, *vec_idx)) {
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off -= uio_iovlen(uio, *vec_idx);
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(*vec_idx)++;
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}
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return (off);
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}
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static inline void
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iov_iter_init_compat(struct iov_iter *iter, unsigned int dir,
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const struct iovec *iov, unsigned long nr_segs, size_t count)
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{
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#if defined(HAVE_IOV_ITER_INIT)
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iov_iter_init(iter, dir, iov, nr_segs, count);
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#elif defined(HAVE_IOV_ITER_INIT_LEGACY)
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iov_iter_init(iter, iov, nr_segs, count, 0);
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#else
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#error "Unsupported kernel"
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#endif
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}
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static inline void
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uio_iovec_init(uio_t *uio, const struct iovec *iov, unsigned long nr_segs,
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offset_t offset, uio_seg_t seg, ssize_t resid, size_t skip)
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{
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ASSERT(seg == UIO_USERSPACE || seg == UIO_SYSSPACE);
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uio->uio_iov = iov;
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uio->uio_iovcnt = nr_segs;
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uio->uio_loffset = offset;
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uio->uio_segflg = seg;
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uio->uio_fault_disable = B_FALSE;
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uio->uio_fmode = 0;
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uio->uio_extflg = 0;
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uio->uio_resid = resid;
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uio->uio_skip = skip;
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}
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static inline void
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uio_bvec_init(uio_t *uio, struct bio *bio)
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{
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uio->uio_bvec = &bio->bi_io_vec[BIO_BI_IDX(bio)];
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uio->uio_iovcnt = bio->bi_vcnt - BIO_BI_IDX(bio);
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uio->uio_loffset = BIO_BI_SECTOR(bio) << 9;
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uio->uio_segflg = UIO_BVEC;
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uio->uio_fault_disable = B_FALSE;
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uio->uio_fmode = 0;
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uio->uio_extflg = 0;
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uio->uio_resid = BIO_BI_SIZE(bio);
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uio->uio_skip = BIO_BI_SKIP(bio);
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}
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#if defined(HAVE_VFS_IOV_ITER)
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static inline void
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uio_iov_iter_init(uio_t *uio, struct iov_iter *iter, offset_t offset,
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ssize_t resid, size_t skip)
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{
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uio->uio_iter = iter;
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uio->uio_iovcnt = iter->nr_segs;
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uio->uio_loffset = offset;
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uio->uio_segflg = UIO_ITER;
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uio->uio_fault_disable = B_FALSE;
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uio->uio_fmode = 0;
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uio->uio_extflg = 0;
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uio->uio_resid = resid;
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uio->uio_skip = skip;
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}
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#endif
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#endif /* SPL_UIO_H */
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