Fix stack traverse_impl()

Stack use reduced from 560 bytes to 128 bytes.

Signed-off-by: Brian Behlendorf <[email protected]>

1 files changed, 36 insertions, 28 deletions

diff --git a/module/zfs/dmu_traverse.c b/module/zfs/dmu_traverse.c
index 023f90e12..fb102c6ca 100644
--- a/module/zfs/dmu_traverse.c
+++ b/module/zfs/dmu_traverse.c
@@ -356,24 +356,28 @@ static int
 traverse_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *rootbp,
     uint64_t txg_start, int flags, blkptr_cb_t func, void *arg)
 {
-	traverse_data_t td;
-	prefetch_data_t pd = { 0 };
-	zbookmark_t czb;
+	traverse_data_t *td;
+	prefetch_data_t *pd;
+	zbookmark_t *czb;
 	int err;
 
-	td.td_spa = spa;
-	td.td_objset = ds ? ds->ds_object : 0;
-	td.td_rootbp = rootbp;
-	td.td_min_txg = txg_start;
-	td.td_func = func;
-	td.td_arg = arg;
-	td.td_pfd = &pd;
-	td.td_flags = flags;
+	td = kmem_alloc(sizeof(traverse_data_t), KM_SLEEP);
+	pd = kmem_zalloc(sizeof(prefetch_data_t), KM_SLEEP);
+	czb = kmem_alloc(sizeof(zbookmark_t), KM_SLEEP);
+
+	td->td_spa = spa;
+	td->td_objset = ds ? ds->ds_object : 0;
+	td->td_rootbp = rootbp;
+	td->td_min_txg = txg_start;
+	td->td_func = func;
+	td->td_arg = arg;
+	td->td_pfd = pd;
+	td->td_flags = flags;
 
-	pd.pd_blks_max = zfs_pd_blks_max;
-	pd.pd_flags = flags;
-	mutex_init(&pd.pd_mtx, NULL, MUTEX_DEFAULT, NULL);
-	cv_init(&pd.pd_cv, NULL, CV_DEFAULT, NULL);
+	pd->pd_blks_max = zfs_pd_blks_max;
+	pd->pd_flags = flags;
+	mutex_init(&pd->pd_mtx, NULL, MUTEX_DEFAULT, NULL);
+	cv_init(&pd->pd_cv, NULL, CV_DEFAULT, NULL);
 
 	/* See comment on ZIL traversal in dsl_scan_visitds. */
 	if (ds != NULL && !dsl_dataset_is_snapshot(ds)) {
@@ -383,27 +387,31 @@ traverse_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *rootbp,
 		if (err)
 			return (err);
 
-		traverse_zil(&td, &os->os_zil_header);
+		traverse_zil(td, &os->os_zil_header);
 	}
 
 	if (!(flags & TRAVERSE_PREFETCH) ||
 	    0 == taskq_dispatch(system_taskq, traverse_prefetch_thread,
-	    &td, TQ_NOQUEUE))
-		pd.pd_exited = B_TRUE;
+	    td, TQ_NOQUEUE))
+		pd->pd_exited = B_TRUE;
 
-	SET_BOOKMARK(&czb, td.td_objset,
+	SET_BOOKMARK(czb, td->td_objset,
 	    ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
-	err = traverse_visitbp(&td, NULL, NULL, rootbp, &czb);
+	err = traverse_visitbp(td, NULL, NULL, rootbp, czb);
+
+	mutex_enter(&pd->pd_mtx);
+	pd->pd_cancel = B_TRUE;
+	cv_broadcast(&pd->pd_cv);
+	while (!pd->pd_exited)
+		cv_wait(&pd->pd_cv, &pd->pd_mtx);
+	mutex_exit(&pd->pd_mtx);
 
-	mutex_enter(&pd.pd_mtx);
-	pd.pd_cancel = B_TRUE;
-	cv_broadcast(&pd.pd_cv);
-	while (!pd.pd_exited)
-		cv_wait(&pd.pd_cv, &pd.pd_mtx);
-	mutex_exit(&pd.pd_mtx);
+	mutex_destroy(&pd->pd_mtx);
+	cv_destroy(&pd->pd_cv);
 
-	mutex_destroy(&pd.pd_mtx);
-	cv_destroy(&pd.pd_cv);
+	kmem_free(czb, sizeof(zbookmark_t));
+	kmem_free(pd, sizeof(struct prefetch_data));
+	kmem_free(td, sizeof(struct traverse_data));
 
 	return (err);
 }