On Sun, Apr 4, 2021 at 9:47 PM Yonghong Song <yhs@xxxxxx> wrote:
>
>
>
> On 3/29/21 5:57 AM, Denis Salopek wrote:
> > Extend the existing bpf_map_lookup_and_delete_elem() functionality to
> > hashtab maps, in addition to stacks and queues.
> > Add bpf_map_lookup_and_delete_elem_flags() libbpf API in order to use
> > the BPF_F_LOCK flag.
> > Create a new hashtab bpf_map_ops function that does lookup and deletion
> > of the element under the same bucket lock and add the created map_ops to
> > bpf.h.
> > Add the appropriate test cases to 'maps' and 'lru_map' selftests
> > accompanied with new test_progs.
> >
> > Cc: Juraj Vijtiuk <juraj.vijtiuk@xxxxxxxxxx>
> > Cc: Luka Oreskovic <luka.oreskovic@xxxxxxxxxx>
> > Cc: Luka Perkov <luka.perkov@xxxxxxxxxx>
> > Signed-off-by: Denis Salopek <denis.salopek@xxxxxxxxxx>
> > ---
> > v2: Add functionality for LRU/per-CPU, add test_progs tests.
> > v3: Add bpf_map_lookup_and_delete_elem_flags() and enable BPF_F_LOCK
> > flag, change CHECKs to ASSERT_OKs, initialize variables to 0.
> > v4: Fix the return value for unsupported map types.
> > ---
> > include/linux/bpf.h | 2 +
> > kernel/bpf/hashtab.c | 97 ++++++
> > kernel/bpf/syscall.c | 27 +-
> > tools/lib/bpf/bpf.c | 13 +
> > tools/lib/bpf/bpf.h | 2 +
> > tools/lib/bpf/libbpf.map | 1 +
> > .../bpf/prog_tests/lookup_and_delete.c | 279 ++++++++++++++++++
> > .../bpf/progs/test_lookup_and_delete.c | 26 ++
> > tools/testing/selftests/bpf/test_lru_map.c | 8 +
> > tools/testing/selftests/bpf/test_maps.c | 19 +-
> > 10 files changed, 469 insertions(+), 5 deletions(-)
> > create mode 100644 tools/testing/selftests/bpf/prog_tests/lookup_and_delete.c
> > create mode 100644 tools/testing/selftests/bpf/progs/test_lookup_and_delete.c
>
[...]
> > +int bpf_map_lookup_and_delete_elem_flags(int fd, const void *key, void *value, __u64 flags)
> > +{
> > + union bpf_attr attr;
> > +
> > + memset(&attr, 0, sizeof(attr));
> > + attr.map_fd = fd;
> > + attr.key = ptr_to_u64(key);
> > + attr.value = ptr_to_u64(value);
> > + attr.flags = flags;
> > +
> > + return sys_bpf(BPF_MAP_LOOKUP_AND_DELETE_ELEM, &attr, sizeof(attr));
> > +}
>
> This looks okay to me. It mimics bpf_map_lookup_elem_flags().
> Andrii, could you take a look as well?
I think it's fine. Given bpf_map_lookup_elem_flags() didn't get
extended for so long means the API is pretty stable and is unlikely to
require the entire OPTS framework.
>
> > +
> > int bpf_map_delete_elem(int fd, const void *key)
> > {
> > union bpf_attr attr;
[...]
