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ba39486d |
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11-May-2024 |
Jose E. Marchesi <jose.marchesi@oracle.com> |
bpf: make list_for_each_entry portable [Changes from V1: - The __compat_break has been abandoned in favor of a more readable can_loop macro that can be used anywhere, including loop conditions.] The macro list_for_each_entry is defined in bpf_arena_list.h as follows: #define list_for_each_entry(pos, head, member) \ for (void * ___tmp = (pos = list_entry_safe((head)->first, \ typeof(*(pos)), member), \ (void *)0); \ pos && ({ ___tmp = (void *)pos->member.next; 1; }); \ cond_break, \ pos = list_entry_safe((void __arena *)___tmp, typeof(*(pos)), member)) The macro cond_break, in turn, expands to a statement expression that contains a `break' statement. Compound statement expressions, and the subsequent ability of placing statements in the header of a `for' loop, are GNU extensions. Unfortunately, clang implements this GNU extension differently than GCC: - In GCC the `break' statement is bound to the containing "breakable" context in which the defining `for' appears. If there is no such context, GCC emits a warning: break statement without enclosing `for' o `switch' statement. - In clang the `break' statement is bound to the defining `for'. If the defining `for' is itself inside some breakable construct, then clang emits a -Wgcc-compat warning. This patch adds a new macro can_loop to bpf_experimental, that implements the same logic than cond_break but evaluates to a boolean expression. The patch also changes all the current instances of usage of cond_break withing the header of loop accordingly. Tested in bpf-next master. No regressions. Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com> Cc: david.faust@oracle.com Cc: cupertino.miranda@oracle.com Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Link: https://lore.kernel.org/r/20240511212243.23477-1-jose.marchesi@oracle.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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10ebe835 |
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14-Mar-2024 |
Alexei Starovoitov <ast@kernel.org> |
libbpf, selftests/bpf: Adjust libbpf, bpftool, selftests to match LLVM The selftests use to tell LLVM about special pointers. For LLVM there is nothing "arena" about them. They are simply pointers in a different address space. Hence LLVM diff https://github.com/llvm/llvm-project/pull/85161 renamed: . macro __BPF_FEATURE_ARENA_CAST -> __BPF_FEATURE_ADDR_SPACE_CAST . global variables in __attribute__((address_space(N))) are now placed in section named ".addr_space.N" instead of ".arena.N". Adjust libbpf, bpftool, and selftests to match LLVM. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/bpf/20240315021834.62988-3-alexei.starovoitov@gmail.com
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