Remove UIO_ZEROCOPY functions structures

The original xuio zero copy functionality has always been unused 
on Linux and FreeBSD.  Remove this disabled code to avoid any
confusion and improve readability.

Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Ryan Moeller <[email protected]>
Signed-off-by: Matt Macy <[email protected]>
Closes #11124 

2 files changed, 0 insertions, 173 deletions

diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c
index 9b6481d22..82bb7206c 100644
--- a/module/zfs/dbuf.c
+++ b/module/zfs/dbuf.c
@@ -2627,11 +2627,9 @@ dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx)
 		(void) dbuf_dirty(db, tx);
 		bcopy(buf->b_data, db->db.db_data, db->db.db_size);
 		arc_buf_destroy(buf, db);
-		xuio_stat_wbuf_copied();
 		return;
 	}
 
-	xuio_stat_wbuf_nocopy();
 	if (db->db_state == DB_CACHED) {
 		dbuf_dirty_record_t *dr = list_head(&db->db_dirty_records);
 
diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c
index 2c9664521..14d864fbc 100644
--- a/module/zfs/dmu.c
+++ b/module/zfs/dmu.c
@@ -1165,165 +1165,12 @@ dmu_redact(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 	dmu_buf_rele_array(dbp, numbufs, FTAG);
 }
 
-/*
- * DMU support for xuio
- */
-kstat_t *xuio_ksp = NULL;
-
-typedef struct xuio_stats {
-	/* loaned yet not returned arc_buf */
-	kstat_named_t xuiostat_onloan_rbuf;
-	kstat_named_t xuiostat_onloan_wbuf;
-	/* whether a copy is made when loaning out a read buffer */
-	kstat_named_t xuiostat_rbuf_copied;
-	kstat_named_t xuiostat_rbuf_nocopy;
-	/* whether a copy is made when assigning a write buffer */
-	kstat_named_t xuiostat_wbuf_copied;
-	kstat_named_t xuiostat_wbuf_nocopy;
-} xuio_stats_t;
-
-static xuio_stats_t xuio_stats = {
-	{ "onloan_read_buf",	KSTAT_DATA_UINT64 },
-	{ "onloan_write_buf",	KSTAT_DATA_UINT64 },
-	{ "read_buf_copied",	KSTAT_DATA_UINT64 },
-	{ "read_buf_nocopy",	KSTAT_DATA_UINT64 },
-	{ "write_buf_copied",	KSTAT_DATA_UINT64 },
-	{ "write_buf_nocopy",	KSTAT_DATA_UINT64 }
-};
-
-#define	XUIOSTAT_INCR(stat, val)        \
-	atomic_add_64(&xuio_stats.stat.value.ui64, (val))
-#define	XUIOSTAT_BUMP(stat)	XUIOSTAT_INCR(stat, 1)
-
-#ifdef HAVE_UIO_ZEROCOPY
-int
-dmu_xuio_init(xuio_t *xuio, int nblk)
-{
-	dmu_xuio_t *priv;
-	uio_t *uio = &xuio->xu_uio;
-
-	uio->uio_iovcnt = nblk;
-	uio->uio_iov = kmem_zalloc(nblk * sizeof (iovec_t), KM_SLEEP);
-
-	priv = kmem_zalloc(sizeof (dmu_xuio_t), KM_SLEEP);
-	priv->cnt = nblk;
-	priv->bufs = kmem_zalloc(nblk * sizeof (arc_buf_t *), KM_SLEEP);
-	priv->iovp = (iovec_t *)uio->uio_iov;
-	XUIO_XUZC_PRIV(xuio) = priv;
-
-	if (XUIO_XUZC_RW(xuio) == UIO_READ)
-		XUIOSTAT_INCR(xuiostat_onloan_rbuf, nblk);
-	else
-		XUIOSTAT_INCR(xuiostat_onloan_wbuf, nblk);
-
-	return (0);
-}
-
-void
-dmu_xuio_fini(xuio_t *xuio)
-{
-	dmu_xuio_t *priv = XUIO_XUZC_PRIV(xuio);
-	int nblk = priv->cnt;
-
-	kmem_free(priv->iovp, nblk * sizeof (iovec_t));
-	kmem_free(priv->bufs, nblk * sizeof (arc_buf_t *));
-	kmem_free(priv, sizeof (dmu_xuio_t));
-
-	if (XUIO_XUZC_RW(xuio) == UIO_READ)
-		XUIOSTAT_INCR(xuiostat_onloan_rbuf, -nblk);
-	else
-		XUIOSTAT_INCR(xuiostat_onloan_wbuf, -nblk);
-}
-
-/*
- * Initialize iov[priv->next] and priv->bufs[priv->next] with { off, n, abuf }
- * and increase priv->next by 1.
- */
-int
-dmu_xuio_add(xuio_t *xuio, arc_buf_t *abuf, offset_t off, size_t n)
-{
-	struct iovec *iov;
-	uio_t *uio = &xuio->xu_uio;
-	dmu_xuio_t *priv = XUIO_XUZC_PRIV(xuio);
-	int i = priv->next++;
-
-	ASSERT(i < priv->cnt);
-	ASSERT(off + n <= arc_buf_lsize(abuf));
-	iov = (iovec_t *)uio->uio_iov + i;
-	iov->iov_base = (char *)abuf->b_data + off;
-	iov->iov_len = n;
-	priv->bufs[i] = abuf;
-	return (0);
-}
-
-int
-dmu_xuio_cnt(xuio_t *xuio)
-{
-	dmu_xuio_t *priv = XUIO_XUZC_PRIV(xuio);
-	return (priv->cnt);
-}
-
-arc_buf_t *
-dmu_xuio_arcbuf(xuio_t *xuio, int i)
-{
-	dmu_xuio_t *priv = XUIO_XUZC_PRIV(xuio);
-
-	ASSERT(i < priv->cnt);
-	return (priv->bufs[i]);
-}
-
-void
-dmu_xuio_clear(xuio_t *xuio, int i)
-{
-	dmu_xuio_t *priv = XUIO_XUZC_PRIV(xuio);
-
-	ASSERT(i < priv->cnt);
-	priv->bufs[i] = NULL;
-}
-#endif /* HAVE_UIO_ZEROCOPY */
-
-static void
-xuio_stat_init(void)
-{
-	xuio_ksp = kstat_create("zfs", 0, "xuio_stats", "misc",
-	    KSTAT_TYPE_NAMED, sizeof (xuio_stats) / sizeof (kstat_named_t),
-	    KSTAT_FLAG_VIRTUAL);
-	if (xuio_ksp != NULL) {
-		xuio_ksp->ks_data = &xuio_stats;
-		kstat_install(xuio_ksp);
-	}
-}
-
-static void
-xuio_stat_fini(void)
-{
-	if (xuio_ksp != NULL) {
-		kstat_delete(xuio_ksp);
-		xuio_ksp = NULL;
-	}
-}
-
-void
-xuio_stat_wbuf_copied(void)
-{
-	XUIOSTAT_BUMP(xuiostat_wbuf_copied);
-}
-
-void
-xuio_stat_wbuf_nocopy(void)
-{
-	XUIOSTAT_BUMP(xuiostat_wbuf_nocopy);
-}
-
 #ifdef _KERNEL
 int
 dmu_read_uio_dnode(dnode_t *dn, uio_t *uio, uint64_t size)
 {
 	dmu_buf_t **dbp;
 	int numbufs, i, err;
-#ifdef HAVE_UIO_ZEROCOPY
-	xuio_t *xuio = NULL;
-#endif
 
 	/*
 	 * NB: we could do this block-at-a-time, but it's nice
@@ -1344,21 +1191,6 @@ dmu_read_uio_dnode(dnode_t *dn, uio_t *uio, uint64_t size)
 		bufoff = uio_offset(uio) - db->db_offset;
 		tocpy = MIN(db->db_size - bufoff, size);
 
-#ifdef HAVE_UIO_ZEROCOPY
-		if (xuio) {
-			dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db;
-			arc_buf_t *dbuf_abuf = dbi->db_buf;
-			arc_buf_t *abuf = dbuf_loan_arcbuf(dbi);
-			err = dmu_xuio_add(xuio, abuf, bufoff, tocpy);
-			if (!err)
-				uio_advance(uio, tocpy);
-
-			if (abuf == dbuf_abuf)
-				XUIOSTAT_BUMP(xuiostat_rbuf_nocopy);
-			else
-				XUIOSTAT_BUMP(xuiostat_rbuf_copied);
-		} else
-#endif
 #ifdef __FreeBSD__
 			err = vn_io_fault_uiomove((char *)db->db_data + bufoff,
 			    tocpy, uio);
@@ -1597,7 +1429,6 @@ dmu_assign_arcbuf_by_dnode(dnode_t *dn, uint64_t offset, arc_buf_t *buf,
 		dbuf_rele(db, FTAG);
 		dmu_write(os, object, offset, blksz, buf->b_data, tx);
 		dmu_return_arcbuf(buf);
-		XUIOSTAT_BUMP(xuiostat_wbuf_copied);
 	}
 
 	return (0);
@@ -2409,7 +2240,6 @@ dmu_init(void)
 	abd_init();
 	zfs_dbgmsg_init();
 	sa_cache_init();
-	xuio_stat_init();
 	dmu_objset_init();
 	dnode_init();
 	zfetch_init();
@@ -2429,7 +2259,6 @@ dmu_fini(void)
 	dbuf_fini();
 	dnode_fini();
 	dmu_objset_fini();
-	xuio_stat_fini();
 	sa_cache_fini();
 	zfs_dbgmsg_fini();
 	abd_fini();