Re: [PATCH v3 1/2] vfio: selftests: Add calloc_assert() helper

[Alex Mastro <amastro@fb.com>]

On Mon, Jun 15, 2026 at 03:51:26PM -0700, David Matlack wrote:
> On Mon, Jun 15, 2026 at 12:45 PM Alex Mastro <amastro@fb.com> wrote:
> >
> > Add a calloc_assert() helper alongside the existing ioctl_assert() and
> > snprintf_assert() helpers.
> >
> > Use it for VFIO selftest allocations that immediately assert a
> > non-NULL result.
> >
> > Assisted-by: Codex:gpt-5.5-high
> > Signed-off-by: Alex Mastro <amastro@fb.com>
> > ---
> >  tools/testing/selftests/vfio/lib/include/libvfio/assert.h    | 10 ++++++++++
> >  tools/testing/selftests/vfio/lib/iommu.c                     | 12 ++++--------
> >  tools/testing/selftests/vfio/lib/iova_allocator.c            |  4 +---
> >  tools/testing/selftests/vfio/lib/sysfs.c                     |  3 +--
> >  tools/testing/selftests/vfio/lib/vfio_pci_device.c           |  6 ++----
> >  .../testing/selftests/vfio/vfio_pci_device_init_perf_test.c  |  4 ++--
> >  6 files changed, 20 insertions(+), 19 deletions(-)
> >
> > diff --git a/tools/testing/selftests/vfio/lib/include/libvfio/assert.h b/tools/testing/selftests/vfio/lib/include/libvfio/assert.h
> > index 77b68c7129a6..f0490a403826 100644
> > --- a/tools/testing/selftests/vfio/lib/include/libvfio/assert.h
> > +++ b/tools/testing/selftests/vfio/lib/include/libvfio/assert.h
> > @@ -3,6 +3,7 @@
> >  #define SELFTESTS_VFIO_LIB_INCLUDE_LIBVFIO_ASSERT_H
> >
> >  #include <stdio.h>
> > +#include <stdlib.h>
> >  #include <string.h>
> >  #include <sys/ioctl.h>
> >
> > @@ -45,6 +46,15 @@
> >         VFIO_LOG_AND_EXIT(_fmt, ##__VA_ARGS__);                 \
> >  } while (0)
> >
> > +#define calloc_assert(_nmemb, _size) ({                                \
> > +       size_t __nmemb = (_nmemb);                              \
> > +       size_t __size = (_size);                                \
> > +       void *__ptr = calloc(__nmemb, __size);                  \
> > +       VFIO_ASSERT_NOT_NULL(__ptr, "calloc(%zu, %zu) failed",  \
> > +                            __nmemb, __size);                  \
> > +       __ptr;                                                  \
> > +})
> > +
> >  #define ioctl_assert(_fd, _op, _arg) do {                                                     \
> >         void *__arg = (_arg);                                                                  \
> >         int __ret = ioctl((_fd), (_op), (__arg));                                              \
> > diff --git a/tools/testing/selftests/vfio/lib/iommu.c b/tools/testing/selftests/vfio/lib/iommu.c
> > index 035dac069d60..31aba9fda8e5 100644
> > --- a/tools/testing/selftests/vfio/lib/iommu.c
> > +++ b/tools/testing/selftests/vfio/lib/iommu.c
> > @@ -286,8 +286,7 @@ static struct vfio_iommu_type1_info *vfio_iommu_get_info(int container_fd)
> >  {
> >         struct vfio_iommu_type1_info *info;
> >
> > -       info = malloc(sizeof(*info));
> > -       VFIO_ASSERT_NOT_NULL(info);
> > +       info = calloc_assert(1, sizeof(*info));
> >
> >         *info = (struct vfio_iommu_type1_info) {
> >                 .argsz = sizeof(*info),
> > @@ -324,8 +323,7 @@ static struct iommu_iova_range *vfio_iommu_iova_ranges(struct iommu *iommu,
> >         cap_range = container_of(hdr, struct vfio_iommu_type1_info_cap_iova_range, header);
> >         VFIO_ASSERT_GT(cap_range->nr_iovas, 0);
> >
> > -       ranges = calloc(cap_range->nr_iovas, sizeof(*ranges));
> > -       VFIO_ASSERT_NOT_NULL(ranges);
> > +       ranges = calloc_assert(cap_range->nr_iovas, sizeof(*ranges));
> >
> >         for (u32 i = 0; i < cap_range->nr_iovas; i++) {
> >                 ranges[i] = (struct iommu_iova_range){
> > @@ -357,8 +355,7 @@ static struct iommu_iova_range *iommufd_iova_ranges(struct iommu *iommu,
> >         VFIO_ASSERT_EQ(errno, EMSGSIZE);
> >         VFIO_ASSERT_GT(query.num_iovas, 0);
> >
> > -       ranges = calloc(query.num_iovas, sizeof(*ranges));
> > -       VFIO_ASSERT_NOT_NULL(ranges);
> > +       ranges = calloc_assert(query.num_iovas, sizeof(*ranges));
> >
> >         query.allowed_iovas = (uintptr_t)ranges;
> >
> > @@ -424,8 +421,7 @@ struct iommu *iommu_init(const char *iommu_mode)
> >         struct iommu *iommu;
> >         int version;
> >
> > -       iommu = calloc(1, sizeof(*iommu));
> > -       VFIO_ASSERT_NOT_NULL(iommu);
> > +       iommu = calloc_assert(1, sizeof(*iommu));
> >
> >         INIT_LIST_HEAD(&iommu->dma_regions);
> >
> > diff --git a/tools/testing/selftests/vfio/lib/iova_allocator.c b/tools/testing/selftests/vfio/lib/iova_allocator.c
> > index 8c1cc86b70cd..2e7d54e1b4c6 100644
> > --- a/tools/testing/selftests/vfio/lib/iova_allocator.c
> > +++ b/tools/testing/selftests/vfio/lib/iova_allocator.c
> > @@ -29,8 +29,7 @@ struct iova_allocator *iova_allocator_init(struct iommu *iommu)
> >         ranges = iommu_iova_ranges(iommu, &nranges);
> >         VFIO_ASSERT_NOT_NULL(ranges);
> >
> > -       allocator = malloc(sizeof(*allocator));
> > -       VFIO_ASSERT_NOT_NULL(allocator);
> > +       allocator = calloc_assert(1, sizeof(*allocator));
> 
> Did you mean to replace malloc() with calloc()? Feel free to add a
> malloc_assert().

Yes! Since all malloc() can be expressed as calloc() (because we shouldn't care
about potentially redundant zeroing overhead), I think the single
calloc_assert() is fine.

> 
> >
> >         *allocator = (struct iova_allocator){
> >                 .ranges = ranges,
> > @@ -90,4 +89,3 @@ iova_t iova_allocator_alloc(struct iova_allocator *allocator, size_t size)
> >                 allocator->range_offset = 0;
> >         }
> >  }
> > -
> > diff --git a/tools/testing/selftests/vfio/lib/sysfs.c b/tools/testing/selftests/vfio/lib/sysfs.c
> > index 11415448b2e2..98a46a2543cd 100644
> > --- a/tools/testing/selftests/vfio/lib/sysfs.c
> > +++ b/tools/testing/selftests/vfio/lib/sysfs.c
> > @@ -107,8 +107,7 @@ char *sysfs_sriov_vf_bdf_get(const char *pf_bdf, int i)
> >         char *out_vf_bdf;
> >
> >         /* Fit "0000:00:00.0" */
> > -       out_vf_bdf = calloc(16, sizeof(char));
> > -       VFIO_ASSERT_NOT_NULL(out_vf_bdf);
> > +       out_vf_bdf = calloc_assert(16, sizeof(char));
> >
> >         snprintf_assert(path, PATH_MAX, "/sys/bus/pci/devices/%s/virtfn%d", pf_bdf, i);
> >         readlink_base(path, "%s", out_vf_bdf);
> > diff --git a/tools/testing/selftests/vfio/lib/vfio_pci_device.c b/tools/testing/selftests/vfio/lib/vfio_pci_device.c
> > index 94dc5fcecbeb..eb40f7159bae 100644
> > --- a/tools/testing/selftests/vfio/lib/vfio_pci_device.c
> > +++ b/tools/testing/selftests/vfio/lib/vfio_pci_device.c
> > @@ -343,8 +343,7 @@ const char *vfio_pci_get_cdev_path(const char *bdf)
> >         char *cdev_path;
> >         DIR *dir;
> >
> > -       cdev_path = calloc(PATH_MAX, 1);
> > -       VFIO_ASSERT_NOT_NULL(cdev_path);
> > +       cdev_path = calloc_assert(PATH_MAX, 1);
> >
> >         snprintf_assert(dir_path, sizeof(dir_path), "/sys/bus/pci/devices/%s/vfio-dev/", bdf);
> >
> > @@ -425,8 +424,7 @@ struct vfio_pci_device *vfio_pci_device_alloc(const char *bdf, struct iommu *iom
> >  {
> >         struct vfio_pci_device *device;
> >
> > -       device = calloc(1, sizeof(*device));
> > -       VFIO_ASSERT_NOT_NULL(device);
> > +       device = calloc_assert(1, sizeof(*device));
> >
> >         VFIO_ASSERT_NOT_NULL(iommu);
> >         device->iommu = iommu;
> > diff --git a/tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c b/tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c
> > index 33b0c31fe2ed..e1a54e153cd3 100644
> > --- a/tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c
> > +++ b/tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c
> > @@ -45,8 +45,8 @@ FIXTURE_SETUP(vfio_pci_device_init_perf_test)
> >         int i;
> >
> >         self->iommu = iommu_init(variant->iommu_mode);
> > -       self->threads = calloc(nr_devices, sizeof(self->threads[0]));
> > -       self->thread_args = calloc(nr_devices, sizeof(self->thread_args[0]));
> > +       self->threads = calloc_assert(nr_devices, sizeof(self->threads[0]));
> > +       self->thread_args = calloc_assert(nr_devices, sizeof(self->thread_args[0]));
> >
> >         pthread_barrier_init(&self->barrier, NULL, nr_devices);
> >
> >
> > --
> > 2.53.0-Meta
> >