[PATCH v2 02/10] KVM: selftests: simplify setup_demand_paging error handling

From: Axel Rasmussen
Date: Wed May 19 2021 - 16:03:57 EST


A small cleanup. Our caller writes:

r = setup_demand_paging(...);
if (r < 0) exit(-r);

Since we're just going to exit anyway, instead of returning an error we
can just re-use TEST_ASSERT. This makes the caller simpler, as well as
the function itself - no need to write our branches, etc.

Signed-off-by: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
---
.../selftests/kvm/demand_paging_test.c | 51 +++++++------------
1 file changed, 19 insertions(+), 32 deletions(-)

diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c
index 9398ba6ef023..601a1df24dd2 100644
--- a/tools/testing/selftests/kvm/demand_paging_test.c
+++ b/tools/testing/selftests/kvm/demand_paging_test.c
@@ -9,6 +9,8 @@

#define _GNU_SOURCE /* for pipe2 */

+#include <inttypes.h>
+#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
@@ -198,42 +200,32 @@ static void *uffd_handler_thread_fn(void *arg)
return NULL;
}

-static int setup_demand_paging(struct kvm_vm *vm,
- pthread_t *uffd_handler_thread, int pipefd,
- useconds_t uffd_delay,
- struct uffd_handler_args *uffd_args,
- void *hva, uint64_t len)
+static void setup_demand_paging(struct kvm_vm *vm,
+ pthread_t *uffd_handler_thread, int pipefd,
+ useconds_t uffd_delay,
+ struct uffd_handler_args *uffd_args,
+ void *hva, uint64_t len)
{
int uffd;
struct uffdio_api uffdio_api;
struct uffdio_register uffdio_register;

uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
- if (uffd == -1) {
- pr_info("uffd creation failed\n");
- return -1;
- }
+ TEST_ASSERT(uffd >= 0, "uffd creation failed, errno: %d", errno);

uffdio_api.api = UFFD_API;
uffdio_api.features = 0;
- if (ioctl(uffd, UFFDIO_API, &uffdio_api) == -1) {
- pr_info("ioctl uffdio_api failed\n");
- return -1;
- }
+ TEST_ASSERT(ioctl(uffd, UFFDIO_API, &uffdio_api) != -1,
+ "ioctl UFFDIO_API failed: %" PRIu64,
+ (uint64_t)uffdio_api.api);

uffdio_register.range.start = (uint64_t)hva;
uffdio_register.range.len = len;
uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
- if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) == -1) {
- pr_info("ioctl uffdio_register failed\n");
- return -1;
- }
-
- if ((uffdio_register.ioctls & UFFD_API_RANGE_IOCTLS) !=
- UFFD_API_RANGE_IOCTLS) {
- pr_info("unexpected userfaultfd ioctl set\n");
- return -1;
- }
+ TEST_ASSERT(ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) != -1,
+ "ioctl UFFDIO_REGISTER failed");
+ TEST_ASSERT((uffdio_register.ioctls & UFFD_API_RANGE_IOCTLS) ==
+ UFFD_API_RANGE_IOCTLS, "unexpected userfaultfd ioctl set");

uffd_args->uffd = uffd;
uffd_args->pipefd = pipefd;
@@ -243,8 +235,6 @@ static int setup_demand_paging(struct kvm_vm *vm,

PER_VCPU_DEBUG("Created uffd thread for HVA range [%p, %p)\n",
hva, hva + len);
-
- return 0;
}

struct test_params {
@@ -321,13 +311,10 @@ static void run_test(enum vm_guest_mode mode, void *arg)
O_CLOEXEC | O_NONBLOCK);
TEST_ASSERT(!r, "Failed to set up pipefd");

- r = setup_demand_paging(vm,
- &uffd_handler_threads[vcpu_id],
- pipefds[vcpu_id * 2],
- p->uffd_delay, &uffd_args[vcpu_id],
- vcpu_hva, vcpu_mem_size);
- if (r < 0)
- exit(-r);
+ setup_demand_paging(vm, &uffd_handler_threads[vcpu_id],
+ pipefds[vcpu_id * 2], p->uffd_delay,
+ &uffd_args[vcpu_id], vcpu_hva,
+ vcpu_mem_size);
}
}

--
2.31.1.751.gd2f1c929bd-goog