Add convenience wrappers for common uio usage

The macOS uio struct is opaque and the API must be used, this
makes the smallest changes to the code for all platforms.

Reviewed-by: Matt Macy <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Jorgen Lundman <[email protected]>
Closes #10412 

2 files changed, 153 insertions, 0 deletions

diff --git a/lib/libspl/include/sys/Makefile.am b/lib/libspl/include/sys/Makefile.am
index 8f9c2fa99..5125b8ac3 100644
--- a/lib/libspl/include/sys/Makefile.am
+++ b/lib/libspl/include/sys/Makefile.am
@@ -39,6 +39,7 @@ libspl_HEADERS = \
 	$(top_srcdir)/lib/libspl/include/sys/types32.h \
 	$(top_srcdir)/lib/libspl/include/sys/types.h \
 	$(top_srcdir)/lib/libspl/include/sys/tzfile.h \
+	$(top_srcdir)/lib/libspl/include/sys/uio.h \
 	$(top_srcdir)/lib/libspl/include/sys/va_list.h \
 	$(top_srcdir)/lib/libspl/include/sys/varargs.h \
 	$(top_srcdir)/lib/libspl/include/sys/vnode.h \
diff --git a/lib/libspl/include/sys/uio.h b/lib/libspl/include/sys/uio.h
new file mode 100644
index 000000000..6d892dd3e
--- /dev/null
+++ b/lib/libspl/include/sys/uio.h
@@ -0,0 +1,152 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
+/*	  All Rights Reserved  	*/
+
+/*
+ * University Copyright- Copyright (c) 1982, 1986, 1988
+ * The Regents of the University of California
+ * All Rights Reserved
+ *
+ * University Acknowledgment- Portions of this document are derived from
+ * software developed by the University of California, Berkeley, and its
+ * contributors.
+ */
+
+#ifndef	_LIBSPL_SYS_UIO_H
+#define	_LIBSPL_SYS_UIO_H
+
+#include <sys/types.h>
+#include_next <sys/uio.h>
+
+#ifdef __APPLE__
+#include <sys/_types/_iovec_t.h>
+#endif
+
+#include <stdint.h>
+typedef struct iovec iovec_t;
+
+#if defined(__linux__) || defined(__APPLE__)
+typedef enum uio_rw {
+	UIO_READ =	0,
+	UIO_WRITE =	1,
+} uio_rw_t;
+
+typedef enum uio_seg {
+	UIO_USERSPACE =	0,
+	UIO_SYSSPACE =	1,
+	UIO_USERISPACE = 2,
+} uio_seg_t;
+
+#elif defined(__FreeBSD__)
+typedef enum uio_seg  uio_seg_t;
+#endif
+
+typedef struct uio {
+	struct iovec	*uio_iov;	/* pointer to array of iovecs */
+	int		uio_iovcnt;	/* number of iovecs */
+	offset_t	uio_loffset;	/* file offset */
+	uio_seg_t	uio_segflg;	/* address space (kernel or user) */
+	uint16_t	uio_fmode;	/* file mode flags */
+	uint16_t	uio_extflg;	/* extended flags */
+	offset_t	uio_limit;	/* u-limit (maximum byte offset) */
+	ssize_t		uio_resid;	/* residual count */
+} uio_t;
+
+typedef enum xuio_type {
+	UIOTYPE_ASYNCIO,
+	UIOTYPE_ZEROCOPY,
+} xuio_type_t;
+
+#define	UIOA_IOV_MAX	16
+
+typedef struct uioa_page_s {		/* locked uio_iov state */
+	int	uioa_pfncnt;		/* count of pfn_t(s) in *uioa_ppp */
+	void	**uioa_ppp;		/* page_t or pfn_t array */
+	caddr_t	uioa_base;		/* address base */
+	size_t	uioa_len;		/* span length */
+} uioa_page_t;
+
+typedef struct xuio {
+	uio_t xu_uio;				/* embedded UIO structure */
+
+	/* Extended uio fields */
+	enum xuio_type xu_type;			/* uio type */
+	union {
+		struct {
+			uint32_t xu_a_state;	/* state of async i/o */
+			ssize_t xu_a_mbytes;	/* bytes moved */
+			uioa_page_t *xu_a_lcur;	/* uioa_locked[] pointer */
+			void **xu_a_lppp;	/* lcur->uioa_pppp[] pointer */
+			void *xu_a_hwst[4];	/* opaque hardware state */
+			uioa_page_t xu_a_locked[UIOA_IOV_MAX];
+		} xu_aio;
+
+		struct {
+			int xu_zc_rw;		/* read or write buffer */
+			void *xu_zc_priv;	/* fs specific */
+		} xu_zc;
+	} xu_ext;
+} xuio_t;
+
+#define	XUIO_XUZC_PRIV(xuio)	xuio->xu_ext.xu_zc.xu_zc_priv
+#define	XUIO_XUZC_RW(xuio)	xuio->xu_ext.xu_zc.xu_zc_rw
+
+#define	uio_segflg(uio)			(uio)->uio_segflg
+#define	uio_offset(uio)			(uio)->uio_loffset
+#define	uio_resid(uio)			(uio)->uio_resid
+#define	uio_iovcnt(uio)			(uio)->uio_iovcnt
+#define	uio_iovlen(uio, idx)		(uio)->uio_iov[(idx)].iov_len
+#define	uio_iovbase(uio, idx)		(uio)->uio_iov[(idx)].iov_base
+
+static inline void
+uio_iov_at_index(uio_t *uio, uint_t idx, void **base, uint64_t *len)
+{
+	*base = uio_iovbase(uio, idx);
+	*len = uio_iovlen(uio, idx);
+}
+
+static inline void
+uio_advance(uio_t *uio, size_t size)
+{
+	uio->uio_resid -= size;
+	uio->uio_loffset += size;
+}
+
+static inline offset_t
+uio_index_at_offset(uio_t *uio, offset_t off, uint_t *vec_idx)
+{
+	*vec_idx = 0;
+	while (*vec_idx < uio_iovcnt(uio) && off >= uio_iovlen(uio, *vec_idx)) {
+		off -= uio_iovlen(uio, *vec_idx);
+		(*vec_idx)++;
+	}
+
+	return (off);
+}
+
+#endif	/* _SYS_UIO_H */