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When discussing[1] exec and posix file locks it was realized that none of the callers of get_files_struct fundamentally needed to call get_files_struct, and that by switching them to helper functions instead it will both simplify their code and remove unnecessary increments of files_struct.count. Those unnecessary increments can result in exec unnecessarily unsharing files_struct which breaking posix locks, and it can result in fget_light having to fallback to fget reducing system performance. Using task_lookup_next_fd_rcu simplifies task_file_seq_get_next, by moving the checking for the maximum file descritor into the generic code, and by remvoing the need for capturing and releasing a reference on files_struct. As the reference count of files_struct no longer needs to be maintained bpf_iter_seq_task_file_info can have it's files member removed and task_file_seq_get_next no longer needs it's fstruct argument. The curr_fd local variable does need to become unsigned to be used with fnext_task. As curr_fd is assigned from and assigned a u32 making curr_fd an unsigned int won't cause problems and might prevent them. [1] https://lkml.kernel.org/r/20180915160423.GA31461@redhat.com Suggested-by: Oleg Nesterov <oleg@redhat.com> v1: https://lkml.kernel.org/r/20200817220425.9389-11-ebiederm@xmission.com Link: https://lkml.kernel.org/r/20201120231441.29911-16-ebiederm@xmission.com Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> |
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| .. | ||
| preload | ||
| arraymap.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_struct_ops_types.h | ||
| btf.c | ||
| cgroup.c | ||
| core.c | ||
| cpumap.c | ||
| devmap.c | ||
| disasm.c | ||
| disasm.h | ||
| dispatcher.c | ||
| hashtab.c | ||
| helpers.c | ||
| inode.c | ||
| local_storage.c | ||
| lpm_trie.c | ||
| Makefile | ||
| map_in_map.c | ||
| map_in_map.h | ||
| map_iter.c | ||
| net_namespace.c | ||
| offload.c | ||
| percpu_freelist.c | ||
| percpu_freelist.h | ||
| prog_iter.c | ||
| queue_stack_maps.c | ||
| reuseport_array.c | ||
| ringbuf.c | ||
| stackmap.c | ||
| syscall.c | ||
| sysfs_btf.c | ||
| task_iter.c | ||
| tnum.c | ||
| trampoline.c | ||
| verifier.c | ||