From 15f5c7aa93fc26fb7ee03c9321510369c6834859 Mon Sep 17 00:00:00 2001
From: avg <avg@FreeBSD.org>
Date: Tue, 20 Jun 2017 16:55:30 +0000
Subject: [PATCH] revert r315852 which introduced zio_buf_alloc_nowait for use
 in vdev_queue_aggregate

I think that the change is still good, but reconciling it with a planned
merge of the ARC buf data scatter-ization is a bit more tedious
than I can handle.

MFC after:	17 days
---
 .../opensolaris/uts/common/fs/zfs/sys/zio.h   |  1 -
 .../uts/common/fs/zfs/vdev_queue.c            |  7 +----
 .../opensolaris/uts/common/fs/zfs/zio.c       | 27 +++++--------------
 3 files changed, 7 insertions(+), 28 deletions(-)

diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h
index 26cbd78476f0..a787877e31f5 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h
@@ -555,7 +555,6 @@ extern zio_t *zio_unique_parent(zio_t *cio);
 extern void zio_add_child(zio_t *pio, zio_t *cio);
 
 extern void *zio_buf_alloc(size_t size);
-extern void *zio_buf_alloc_nowait(size_t size);
 extern void zio_buf_free(void *buf, size_t size);
 extern void *zio_data_buf_alloc(size_t size);
 extern void zio_data_buf_free(void *buf, size_t size);
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_queue.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_queue.c
index 8ab39c21bd64..86445f70de0b 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_queue.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_queue.c
@@ -647,7 +647,6 @@ static zio_t *
 vdev_queue_aggregate(vdev_queue_t *vq, zio_t *zio)
 {
 	zio_t *first, *last, *aio, *dio, *mandatory, *nio;
-	void *abuf;
 	uint64_t maxgap = 0;
 	uint64_t size;
 	boolean_t stretch;
@@ -766,12 +765,8 @@ vdev_queue_aggregate(vdev_queue_t *vq, zio_t *zio)
 	size = IO_SPAN(first, last);
 	ASSERT3U(size, <=, SPA_MAXBLOCKSIZE);
 
-	abuf = zio_buf_alloc_nowait(size);
-	if (abuf == NULL)
-		return (NULL);
-
 	aio = zio_vdev_delegated_io(first->io_vd, first->io_offset,
-	    abuf, size, first->io_type, zio->io_priority,
+	    zio_buf_alloc(size), size, first->io_type, zio->io_priority,
 	    flags | ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_QUEUE,
 	    vdev_queue_agg_io_done, NULL);
 	aio->io_timestamp = first->io_timestamp;
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
index 60ff16848d4e..7ff72c7e481b 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
@@ -272,33 +272,18 @@ zio_fini(void)
  * useful to inspect ZFS metadata, but if possible, we should avoid keeping
  * excess / transient data in-core during a crashdump.
  */
-static void *
-zio_buf_alloc_impl(size_t size, boolean_t canwait)
+void *
+zio_buf_alloc(size_t size)
 {
 	size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
 	int flags = zio_exclude_metadata ? KM_NODEBUG : 0;
 
 	VERIFY3U(c, <, SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
 
-	if (zio_use_uma) {
-		return (kmem_cache_alloc(zio_buf_cache[c],
-		    canwait ? KM_PUSHPAGE : KM_NOSLEEP));
-	} else {
-		return (kmem_alloc(size,
-		    (canwait ? KM_SLEEP : KM_NOSLEEP) | flags));
-	}
-}
-
-void *
-zio_buf_alloc(size_t size)
-{
-	return (zio_buf_alloc_impl(size, B_TRUE));
-}
-
-void *
-zio_buf_alloc_nowait(size_t size)
-{
-	return (zio_buf_alloc_impl(size, B_FALSE));
+	if (zio_use_uma)
+		return (kmem_cache_alloc(zio_buf_cache[c], KM_PUSHPAGE));
+	else
+		return (kmem_alloc(size, KM_SLEEP|flags));
 }
 
 /*