From: Mykyta Yatsenko freader_fetch currently reads from at most two folios. When a read spans into a third folio, the overflow bytes are copied adjacent to the second folio’s data instead of being handled as a separate folio. This patch modifies fetch algorithm to support reading from many folios. Signed-off-by: Mykyta Yatsenko Reviewed-by: Andrii Nakryiko --- lib/buildid.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) diff --git a/lib/buildid.c b/lib/buildid.c index df06e492810d..aaf61dfc0919 100644 --- a/lib/buildid.c +++ b/lib/buildid.c @@ -108,18 +108,21 @@ const void *freader_fetch(struct freader *r, loff_t file_off, size_t sz) */ folio_sz = folio_size(r->folio); if (file_off + sz > r->folio_off + folio_sz) { - int part_sz = r->folio_off + folio_sz - file_off; - - /* copy the part that resides in the current folio */ - memcpy(r->buf, r->addr + (file_off - r->folio_off), part_sz); - - /* fetch next folio */ - r->err = freader_get_folio(r, r->folio_off + folio_sz); - if (r->err) - return NULL; - - /* copy the rest of requested data */ - memcpy(r->buf + part_sz, r->addr, sz - part_sz); + u64 part_sz = r->folio_off + folio_sz - file_off, off; + + memcpy(r->buf, r->addr + file_off - r->folio_off, part_sz); + off = part_sz; + + while (off < sz) { + /* fetch next folio */ + r->err = freader_get_folio(r, r->folio_off + folio_sz); + if (r->err) + return NULL; + folio_sz = folio_size(r->folio); + part_sz = min_t(u64, sz - off, folio_sz); + memcpy(r->buf + off, r->addr, part_sz); + off += part_sz; + } return r->buf; } -- 2.51.0