[PATCH 05/20] KVM: selftests: Use goto instead of do-while to retry finding unused physical pages

[Sean Christopherson <seanjc@google.com>]

From: Nicholas Piggin <npiggin@gmail.com>

Rework the core loop of the physical page allocator to use a goto instead
of do-while loop when retrying with a new base address.  The do-while loop
obviously works, but it obfuscates the success vs. failure paths, and in
general is convoluted.

For all intents and purposes, no functional change intended.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[Rebased to latest mainline tree]
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
[sean: separate from alignment change, use enomem label, write changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 tools/testing/selftests/kvm/lib/kvm_util.c | 32 +++++++++++-----------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index b071d77dd301..bbf6d7684c0c 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -2049,23 +2049,15 @@ gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages, gpa_t min_gpa,
 	TEST_ASSERT(!protected || region->protected_phy_pages,
 		    "Region doesn't support protected memory");
 
-	base = pg = min_gpa >> vm->page_shift;
-	do {
-		for (; pg < base + nr_pages; ++pg) {
-			if (!sparsebit_is_set(region->unused_phy_pages, pg)) {
-				base = pg = sparsebit_next_set(region->unused_phy_pages, pg);
-				break;
-			}
+	base = min_gpa >> vm->page_shift;
+again:
+	for (pg = base; pg < base + nr_pages; ++pg) {
+		if (!sparsebit_is_set(region->unused_phy_pages, pg)) {
+			base = sparsebit_next_set(region->unused_phy_pages, pg);
+			if (!base)
+				goto enomem;
+			goto again;
 		}
-	} while (pg && pg != base + nr_pages);
-
-	if (pg == 0) {
-		fprintf(stderr, "No guest physical page available, "
-			"min_gpa: 0x%lx page_size: 0x%x memslot: %u\n",
-			min_gpa, vm->page_size, memslot);
-		fputs("---- vm dump ----\n", stderr);
-		vm_dump(stderr, vm, 2);
-		abort();
 	}
 
 	for (pg = base; pg < base + nr_pages; ++pg) {
@@ -2075,6 +2067,14 @@ gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages, gpa_t min_gpa,
 	}
 
 	return base * vm->page_size;
+
+enomem:
+	fprintf(stderr, "No guest physical page available, min_gpa: 0x%lx page_size: 0x%x memslot: %u\n",
+		min_gpa, vm->page_size, memslot);
+	fputs("---- vm dump ----\n", stderr);
+	vm_dump(stderr, vm, 2);
+	abort();
+	__builtin_unreachable();
 }
 
 gpa_t vm_phy_page_alloc(struct kvm_vm *vm, gpa_t min_gpa, u32 memslot)
-- 
2.55.0.887.g758fc8c411-goog