The reason why p exists in perf_header__adds_write(), even though it is initialized to point the same address as feat_sec points, is that p is increamented in do_write_feat() while feat_sec is not. Note:(*p)++ in do_write_feat() is equivalent to p++ in perf_header__adds_write().
However for this purpose feat_sec can be copied as a local variable of do_write_feat() by being passed as an argument, because p is never used outside of do_write_feat(). Signed-off-by: Soramichi Akiyama <[email protected]> --- tools/perf/util/header.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 00fd8a8..d373661 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -2278,7 +2278,7 @@ int perf_header__fprintf_info(struct perf_session *session, FILE *fp, bool full) } static int do_write_feat(int fd, struct perf_header *h, int type, - struct perf_file_section **p, + struct perf_file_section *p, struct perf_evlist *evlist) { int err; @@ -2288,19 +2288,19 @@ static int do_write_feat(int fd, struct perf_header *h, int type, if (!feat_ops[type].write) return -1; - (*p)->offset = lseek(fd, 0, SEEK_CUR); + p->offset = lseek(fd, 0, SEEK_CUR); err = feat_ops[type].write(fd, h, evlist); if (err < 0) { pr_debug("failed to write feature %s\n", feat_ops[type].name); /* undo anything written */ - lseek(fd, (*p)->offset, SEEK_SET); + lseek(fd, p->offset, SEEK_SET); return -1; } - (*p)->size = lseek(fd, 0, SEEK_CUR) - (*p)->offset; - (*p)++; + p->size = lseek(fd, 0, SEEK_CUR) - p->offset; + p++; } return ret; } @@ -2309,7 +2309,7 @@ static int perf_header__adds_write(struct perf_header *header, struct perf_evlist *evlist, int fd) { int nr_sections; - struct perf_file_section *feat_sec, *p; + struct perf_file_section *feat_sec; int sec_size; u64 sec_start; int feat; @@ -2319,7 +2319,7 @@ static int perf_header__adds_write(struct perf_header *header, if (!nr_sections) return 0; - feat_sec = p = calloc(nr_sections, sizeof(*feat_sec)); + feat_sec = calloc(nr_sections, sizeof(*feat_sec)); if (feat_sec == NULL) return -ENOMEM; @@ -2329,7 +2329,7 @@ static int perf_header__adds_write(struct perf_header *header, lseek(fd, sec_start + sec_size, SEEK_SET); for_each_set_bit(feat, header->adds_features, HEADER_FEAT_BITS) { - if (do_write_feat(fd, header, feat, &p, evlist)) + if (do_write_feat(fd, header, feat, feat_sec, evlist)) perf_header__clear_feat(header, feat); } -- 2.1.4
