git: 069ec467c1b3 - stable/13 - iommu_gas: Drop needless bound check in lowermatch

The branch stable/13 has been updated by dougm:

URL: https://cgit.FreeBSD.org/src/commit/?id=069ec467c1b3c2b774e139f69242f65fd5559343

commit 069ec467c1b3c2b774e139f69242f65fd5559343
Author:     Doug Moore <dougm@FreeBSD.org>
AuthorDate: 2022-06-21 00:34:46 +0000
Commit:     Doug Moore <dougm@FreeBSD.org>
CommitDate: 2022-07-12 17:37:48 +0000

    iommu_gas: Drop needless bound check in lowermatch
    
    The loop iteration in iommu_gas_lowermatch checks the bound
    a->common->lowaddr twice per loop iteration. Rewrite to test only once
    per iteration.  Do not worry about passing to iommu_gas_match_one a
    range wholly beyond lowaddr. Since that function checks the upper end
    of the range against lowaddr, it'll get rejected there.
    
    Reviewed by:    alc
    MFC after:      3 weeks
    Differential Revision:  https://reviews.freebsd.org/D35522
    
    (cherry picked from commit 70b5d8fa0f9457833027e4a1c57b4e68a9351cac)
---
 sys/dev/iommu/iommu_gas.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/sys/dev/iommu/iommu_gas.c b/sys/dev/iommu/iommu_gas.c
index 8007aa575e00..f94ab3756c7b 100644
--- a/sys/dev/iommu/iommu_gas.c
+++ b/sys/dev/iommu/iommu_gas.c
@@ -397,16 +397,11 @@ iommu_gas_lowermatch(struct iommu_gas_match_args *a, struct iommu_map_entry *ent
 	 */
 	entry = first;
 	while (entry != NULL) {
-		if ((first = RB_LEFT(entry, rb_entry)) != NULL) {
-			if (first->last >= a->common->lowaddr) {
-				/* All remaining ranges >= lowaddr */
-				break;
-			}
-			if (iommu_gas_match_one(a, first->last, entry->start,
-			    a->common->lowaddr)) {
-				iommu_gas_match_insert(a);
-				return (0);
-			}
+		if ((first = RB_LEFT(entry, rb_entry)) != NULL &&
+		    iommu_gas_match_one(a, first->last, entry->start,
+		    a->common->lowaddr)) {
+			iommu_gas_match_insert(a);
+			return (0);
 		}
 		if (entry->end >= a->common->lowaddr) {
 			/* All remaining ranges >= lowaddr */