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9bac675e63
A later patch will enable the uptr usage in the task_local_storage map. This will require the unpin_user_page() to be done after the rcu task trace gp for the cases that the uptr may still be used by a bpf prog. The bpf_obj_free_fields() will be the one doing unpin_user_page(), so this patch is to postpone calling bpf_obj_free_fields() to the rcu callback. The bpf_obj_free_fields() is only required to be done in the rcu callback when bpf->bpf_ma==true and reuse_now==false. bpf->bpf_ma==true case is because uptr will only be enabled in task storage which has already been moved to bpf_mem_alloc. The bpf->bpf_ma==false case can be supported in the future also if there is a need. reuse_now==false when the selem (aka storage) is deleted by bpf prog (bpf_task_storage_delete) or by syscall delete_elem(). In both cases, bpf_obj_free_fields() needs to wait for rcu gp. A few words on reuse_now==true. reuse_now==true when the storage's owner (i.e. the task_struct) is destructing or the map itself is doing map_free(). In both cases, no bpf prog should have a hold on the selem and its uptrs, so there is no need to postpone bpf_obj_free_fields(). reuse_now==true should be the common case for local storage usage where the storage exists throughout the lifetime of its owner (task_struct). The bpf_obj_free_fields() needs to use the map->record. Doing bpf_obj_free_fields() in a rcu callback will require the bpf_local_storage_map_free() to wait for rcu_barrier. An optimization could be only waiting for rcu_barrier when the map has uptr in its map_value. This will require either yet another rcu callback function or adding a bool in the selem to flag if the SDATA(selem)->smap is still valid. This patch chooses to keep it simple and wait for rcu_barrier for maps that use bpf_mem_alloc. Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://lore.kernel.org/r/20241023234759.860539-6-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org> |
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| .. | ||
| preload | ||
| arena.c | ||
| arraymap.c | ||
| bloom_filter.c | ||
| bpf_cgrp_storage.c | ||
| bpf_inode_storage.c | ||
| bpf_iter.c | ||
| bpf_local_storage.c | ||
| bpf_lru_list.c | ||
| bpf_lru_list.h | ||
| bpf_lsm.c | ||
| bpf_struct_ops.c | ||
| bpf_task_storage.c | ||
| btf_iter.c | ||
| btf_relocate.c | ||
| btf.c | ||
| cgroup_iter.c | ||
| cgroup.c | ||
| core.c | ||
| cpumap.c | ||
| cpumask.c | ||
| crypto.c | ||
| devmap.c | ||
| disasm.c | ||
| disasm.h | ||
| dispatcher.c | ||
| hashtab.c | ||
| helpers.c | ||
| inode.c | ||
| Kconfig | ||
| kmem_cache_iter.c | ||
| link_iter.c | ||
| local_storage.c | ||
| log.c | ||
| lpm_trie.c | ||
| Makefile | ||
| map_in_map.c | ||
| map_in_map.h | ||
| map_iter.c | ||
| memalloc.c | ||
| mmap_unlock_work.h | ||
| mprog.c | ||
| net_namespace.c | ||
| offload.c | ||
| percpu_freelist.c | ||
| percpu_freelist.h | ||
| prog_iter.c | ||
| queue_stack_maps.c | ||
| relo_core.c | ||
| reuseport_array.c | ||
| ringbuf.c | ||
| stackmap.c | ||
| syscall.c | ||
| sysfs_btf.c | ||
| task_iter.c | ||
| tcx.c | ||
| tnum.c | ||
| token.c | ||
| trampoline.c | ||
| verifier.c | ||