Cleanup: Remove ineffective unsigned comparisons against 0

Coverity found a number of places where we either do MAX(unsigned, 0) or
do assertions that a unsigned variable is >= 0. These do nothing, so
let us drop them all.

It also found a spot where we do `if (unsigned >= 0 && ...)`. Let us
also drop the unsigned >= 0 check.

Reviewed-by: Neal Gompa <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Richard Yao <[email protected]>
Closes #13871 

8 files changed, 5 insertions, 9 deletions

diff --git a/module/icp/algs/blake3/blake3_impl.c b/module/icp/algs/blake3/blake3_impl.c
index 5276fd88f..1692916ce 100644
--- a/module/icp/algs/blake3/blake3_impl.c
+++ b/module/icp/algs/blake3/blake3_impl.c
@@ -155,7 +155,6 @@ blake3_impl_setid(uint32_t id)
 		atomic_swap_32(&blake3_impl_chosen, IMPL_CYCLE);
 		break;
 	default:
-		ASSERT3U(id, >=, 0);
 		ASSERT3U(id, <, blake3_supp_impls_cnt);
 		atomic_swap_32(&blake3_impl_chosen, id);
 		break;
diff --git a/module/os/freebsd/zfs/zfs_acl.c b/module/os/freebsd/zfs/zfs_acl.c
index ad482ee9d..963102f3b 100644
--- a/module/os/freebsd/zfs/zfs_acl.c
+++ b/module/os/freebsd/zfs/zfs_acl.c
@@ -527,7 +527,7 @@ zfs_acl_valid_ace_type(uint_t type, uint_t flags)
 		    entry_type == ACE_EVERYONE || entry_type == 0 ||
 		    entry_type == ACE_IDENTIFIER_GROUP);
 	default:
-		if (type >= MIN_ACE_TYPE && type <= MAX_ACE_TYPE)
+		if (type <= MAX_ACE_TYPE)
 			return (B_TRUE);
 	}
 	return (B_FALSE);
diff --git a/module/os/linux/zfs/zfs_acl.c b/module/os/linux/zfs/zfs_acl.c
index 4fd071d3c..5935403b4 100644
--- a/module/os/linux/zfs/zfs_acl.c
+++ b/module/os/linux/zfs/zfs_acl.c
@@ -525,7 +525,7 @@ zfs_acl_valid_ace_type(uint_t type, uint_t flags)
 		    entry_type == ACE_EVERYONE || entry_type == 0 ||
 		    entry_type == ACE_IDENTIFIER_GROUP);
 	default:
-		if (type >= MIN_ACE_TYPE && type <= MAX_ACE_TYPE)
+		if (type <= MAX_ACE_TYPE)
 			return (B_TRUE);
 	}
 	return (B_FALSE);
diff --git a/module/os/linux/zfs/zvol_os.c b/module/os/linux/zfs/zvol_os.c
index 8904dc5bb..0d4e0dcd5 100644
--- a/module/os/linux/zfs/zvol_os.c
+++ b/module/os/linux/zfs/zvol_os.c
@@ -1433,7 +1433,7 @@ zvol_os_create_minor(const char *name)
 	 * Prefetching the blocks commonly scanned by blkid(8) will speed
 	 * up this process.
 	 */
-	len = MIN(MAX(zvol_prefetch_bytes, 0), SPA_MAXBLOCKSIZE);
+	len = MIN(zvol_prefetch_bytes, SPA_MAXBLOCKSIZE);
 	if (len > 0) {
 		dmu_prefetch(os, ZVOL_OBJ, 0, 0, len, ZIO_PRIORITY_SYNC_READ);
 		dmu_prefetch(os, ZVOL_OBJ, 0, volsize - len, len,
diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index b9969bff5..7957b1b56 100644
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -7664,7 +7664,7 @@ arc_tuning_update(boolean_t verbose)
 
 	/* Valid range: 0 - <all physical memory> */
 	if ((zfs_arc_sys_free) && (zfs_arc_sys_free != arc_sys_free))
-		arc_sys_free = MIN(MAX(zfs_arc_sys_free, 0), allmem);
+		arc_sys_free = MIN(zfs_arc_sys_free, allmem);
 	WARN_IF_TUNING_IGNORED(zfs_arc_sys_free, arc_sys_free, verbose);
 }
 
diff --git a/module/zfs/dsl_dataset.c b/module/zfs/dsl_dataset.c
index a7aca48aa..c9d0a9940 100644
--- a/module/zfs/dsl_dataset.c
+++ b/module/zfs/dsl_dataset.c
@@ -2128,8 +2128,6 @@ dsl_livelist_should_disable(dsl_dataset_t *ds)
 
 	used = dsl_dir_get_usedds(ds->ds_dir);
 	referenced = dsl_get_referenced(ds);
-	ASSERT3U(referenced, >=, 0);
-	ASSERT3U(used, >=, 0);
 	if (referenced == 0)
 		return (B_FALSE);
 	percent_shared = (100 * (referenced - used)) / referenced;
diff --git a/module/zfs/refcount.c b/module/zfs/refcount.c
index b215df98d..c65228457 100644
--- a/module/zfs/refcount.c
+++ b/module/zfs/refcount.c
@@ -137,7 +137,6 @@ zfs_refcount_add_many(zfs_refcount_t *rc, uint64_t number, const void *holder)
 	ref->ref_holder = holder;
 	ref->ref_number = number;
 	mutex_enter(&rc->rc_mtx);
-	ASSERT3U(rc->rc_count, >=, 0);
 	list_insert_head(&rc->rc_list, ref);
 	rc->rc_count += number;
 	count = rc->rc_count;
diff --git a/module/zfs/vdev_queue.c b/module/zfs/vdev_queue.c
index 9a805f2c3..7acb9915c 100644
--- a/module/zfs/vdev_queue.c
+++ b/module/zfs/vdev_queue.c
@@ -614,7 +614,7 @@ vdev_queue_aggregate(vdev_queue_t *vq, zio_t *zio)
 		limit = zfs_vdev_aggregation_limit_non_rotating;
 	else
 		limit = zfs_vdev_aggregation_limit;
-	limit = MAX(MIN(limit, maxblocksize), 0);
+	limit = MIN(limit, maxblocksize);
 
 	if (zio->io_flags & ZIO_FLAG_DONT_AGGREGATE || limit == 0)
 		return (NULL);