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| author | Dave Marchevsky <davemarchevsky@fb.com> | 2023-10-13 13:44:24 -0700 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2023-10-13 15:48:58 -0700 |
| commit | 4ac4546821584736798aaa9e97da9f6eaf689ea3 (patch) | |
| tree | afa500eeb71da22784f72b1caa74a3b47dc35319 /kernel/bpf/helpers.c | |
| parent | 45b38941c81f16bb2e9b0115f03e164a3576ea8b (diff) | |
| download | lwn-4ac4546821584736798aaa9e97da9f6eaf689ea3.tar.gz lwn-4ac4546821584736798aaa9e97da9f6eaf689ea3.zip | |
bpf: Introduce task_vma open-coded iterator kfuncs
This patch adds kfuncs bpf_iter_task_vma_{new,next,destroy} which allow
creation and manipulation of struct bpf_iter_task_vma in open-coded
iterator style. BPF programs can use these kfuncs directly or through
bpf_for_each macro for natural-looking iteration of all task vmas.
The implementation borrows heavily from bpf_find_vma helper's locking -
differing only in that it holds the mmap_read lock for all iterations
while the helper only executes its provided callback on a maximum of 1
vma. Aside from locking, struct vma_iterator and vma_next do all the
heavy lifting.
A pointer to an inner data struct, struct bpf_iter_task_vma_data, is the
only field in struct bpf_iter_task_vma. This is because the inner data
struct contains a struct vma_iterator (not ptr), whose size is likely to
change under us. If bpf_iter_task_vma_kern contained vma_iterator directly
such a change would require change in opaque bpf_iter_task_vma struct's
size. So better to allocate vma_iterator using BPF allocator, and since
that alloc must already succeed, might as well allocate all iter fields,
thereby freezing struct bpf_iter_task_vma size.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231013204426.1074286-4-davemarchevsky@fb.com
Diffstat (limited to 'kernel/bpf/helpers.c')
| -rw-r--r-- | kernel/bpf/helpers.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index d2840dd5b00d..62a53ebfedf9 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2552,6 +2552,9 @@ BTF_ID_FLAGS(func, bpf_dynptr_slice_rdwr, KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_num_new, KF_ITER_NEW) BTF_ID_FLAGS(func, bpf_iter_num_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_num_destroy, KF_ITER_DESTROY) +BTF_ID_FLAGS(func, bpf_iter_task_vma_new, KF_ITER_NEW | KF_RCU) +BTF_ID_FLAGS(func, bpf_iter_task_vma_next, KF_ITER_NEXT | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_iter_task_vma_destroy, KF_ITER_DESTROY) BTF_ID_FLAGS(func, bpf_dynptr_adjust) BTF_ID_FLAGS(func, bpf_dynptr_is_null) BTF_ID_FLAGS(func, bpf_dynptr_is_rdonly) |