Author: mav
Date: Fri Oct 12 16:55:28 2018
New Revision: 339335
URL: https://svnweb.freebsd.org/changeset/base/339335
Log:
Avoid zero-sized kmem_alloc() in vdev_compact_children().
The device evacuation code adds a dependency that
vdev_compact_children() be able to properly empty the vdev_child
array by setting it to NULL and zeroing vdev_children. Under Linux,
kmem_alloc() and related functions return a sentinel pointer rather
than NULL for zero-sized allocations.
This is a part of ZoL port of device removal patch:
commit a1d477c24c7badc89c60955995fd84d311938486
Author: Matthew Ahrens <mahr...@delphix.com>
Ported-by: Tim Chase <t...@chase2k.com>
Approved by: re (kib)
MFC after: 1 week
Modified:
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev.c
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev.c Fri Oct 12
16:24:49 2018 (r339334)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev.c Fri Oct 12
16:55:28 2018 (r339335)
@@ -505,17 +505,24 @@ vdev_compact_children(vdev_t *pvd)
ASSERT(spa_config_held(pvd->vdev_spa, SCL_ALL, RW_WRITER) == SCL_ALL);
+ if (oldc == 0)
+ return;
+
for (int c = newc = 0; c < oldc; c++)
if (pvd->vdev_child[c])
newc++;
- newchild = kmem_alloc(newc * sizeof (vdev_t *), KM_SLEEP);
+ if (newc > 0) {
+ newchild = kmem_alloc(newc * sizeof (vdev_t *), KM_SLEEP);
- for (int c = newc = 0; c < oldc; c++) {
- if ((cvd = pvd->vdev_child[c]) != NULL) {
- newchild[newc] = cvd;
- cvd->vdev_id = newc++;
+ for (int c = newc = 0; c < oldc; c++) {
+ if ((cvd = pvd->vdev_child[c]) != NULL) {
+ newchild[newc] = cvd;
+ cvd->vdev_id = newc++;
+ }
}
+ } else {
+ newchild = NULL;
}
kmem_free(pvd->vdev_child, oldc * sizeof (vdev_t *));
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