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Martin KaFai Lau f0187f0b17 bpf: libbpf: Refactor and bug fix on the bpf_func_info loading logic 
This patch refactor and fix a bug in the libbpf's bpf_func_info loading
logic.  The bug fix and refactoring are targeting the same
commit 2993e0515b ("tools/bpf: add support to read .BTF.ext sections")
which is in the bpf-next branch.

1) In bpf_load_program_xattr(), it should retry when errno == E2BIG
   regardless of log_buf and log_buf_sz.  This patch fixes it.

2) btf_ext__reloc_init() and btf_ext__reloc() are essentially
   the same except btf_ext__reloc_init() always has insns_cnt == 0.
   Hence, btf_ext__reloc_init() is removed.

   btf_ext__reloc() is also renamed to btf_ext__reloc_func_info()
   to get ready for the line_info support in the next patch.

3) Consolidate func_info section logic from "btf_ext_parse_hdr()",
   "btf_ext_validate_func_info()" and "btf_ext__new()" to
   a new function "btf_ext_copy_func_info()" such that similar
   logic can be reused by the later libbpf's line_info patch.

4) The next line_info patch will store line_info_cnt instead of
   line_info_len in the bpf_program because the kernel is taking
   line_info_cnt also.  It will save a few "len" to "cnt" conversions
   and will also save some function args.

   Hence, this patch also makes bpf_program to store func_info_cnt
   instead of func_info_len.

5) btf_ext depends on btf.  e.g. the func_info's type_id
   in ".BTF.ext" is not useful when ".BTF" is absent.
   This patch only init the obj->btf_ext pointer after
   it has successfully init the obj->btf pointer.

   This can avoid always checking "obj->btf && obj->btf_ext"
   together for accessing ".BTF.ext".  Checking "obj->btf_ext"
   alone will do.

6) Move "struct btf_sec_func_info" from btf.h to btf.c.
   There is no external usage outside btf.c.

Fixes: 2993e0515b ("tools/bpf: add support to read .BTF.ext sections")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
 		2018-12-09 13:54:38 -08:00
..
api perf tools: Fix tracing_path_mount proper path 2018-10-16 12:27:46 -03:00
bpf bpf: libbpf: Refactor and bug fix on the bpf_func_info loading logic 2018-12-09 13:54:38 -08:00
lockdep tools lib traceevent, tools lib lockdep: Rename 'enum pevent_errno' to 'enum tep_errno' 2018-08-13 15:23:07 -03:00
subcmd tools lib subcmd: Introduce OPTION_ULONG 2018-10-19 11:56:58 -03:00
symbol tools lib symbols: Introduce kallsyms__is_function() 2018-04-26 13:47:14 -03:00
traceevent tools lib traceevent, perf tools: Move struct tep_handler definition in a local header file 2018-10-08 15:05:37 -03:00
bitmap.c tools lib: Add bitmap_and function 2016-08-02 16:33:27 -03:00
find_bit.c lib: optimize cpumask_next_and() 2018-02-06 18:32:44 -08:00
hweight.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rbtree.c tools: Copy lib/rbtree.c to tools/lib/ 2015-07-05 22:48:21 -03:00
str_error_r.c objtool, perf: Fix GCC 8 -Wrestrict error 2018-03-19 13:51:54 -03:00
string.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vsprintf.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00