6.1-stable review patch. If anyone has any objections, please let me know.
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From: Gao Xiang hsiangkao@linux.alibaba.com
[ Upstream commit 05b63d2beb8b0f752d1f5cdd051c8bdbf532cedd ]
If non-bootstrap bvecs cannot be kept in place (very rarely), an extra short-lived page is allocated.
Let's just allocate it immediately rather than do unnecessary -EAGAIN return first and retry as a cleanup. Also it's unnecessary to use __GFP_NOFAIL here since we could gracefully fail out this case instead.
Signed-off-by: Gao Xiang hsiangkao@linux.alibaba.com Reviewed-by: Yue Hu huyue2@coolpad.com Link: https://lore.kernel.org/r/20230526201459.128169-2-hsiangkao@linux.alibaba.co... Stable-dep-of: 99f7619a77a0 ("erofs: fix to add missing tracepoint in erofs_read_folio()") Signed-off-by: Sasha Levin sashal@kernel.org --- fs/erofs/zdata.c | 32 ++++++++++++-------------------- 1 file changed, 12 insertions(+), 20 deletions(-)
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index 50dd104dbaabf..ff82610eb14c9 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -238,12 +238,17 @@ static int z_erofs_bvec_enqueue(struct z_erofs_bvec_iter *iter, struct z_erofs_bvec *bvec, struct page **candidate_bvpage) { - if (iter->cur == iter->nr) { - if (!*candidate_bvpage) - return -EAGAIN; - + if (iter->cur >= iter->nr) { + struct page *nextpage = *candidate_bvpage; + + if (!nextpage) { + nextpage = alloc_page(GFP_NOFS); + if (!nextpage) + return -ENOMEM; + set_page_private(nextpage, Z_EROFS_SHORTLIVED_PAGE); + } DBG_BUGON(iter->bvset->nextpage); - iter->bvset->nextpage = *candidate_bvpage; + iter->bvset->nextpage = nextpage; z_erofs_bvset_flip(iter);
iter->bvset->nextpage = NULL; @@ -744,10 +749,8 @@ static bool z_erofs_collector_end(struct z_erofs_decompress_frontend *fe) z_erofs_bvec_iter_end(&fe->biter); mutex_unlock(&pcl->lock);
- if (fe->candidate_bvpage) { - DBG_BUGON(z_erofs_is_shortlived_page(fe->candidate_bvpage)); + if (fe->candidate_bvpage) fe->candidate_bvpage = NULL; - }
/* * if all pending pages are added, don't hold its reference @@ -896,24 +899,13 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe, if (cur) tight &= (fe->mode >= Z_EROFS_PCLUSTER_FOLLOWED);
-retry: err = z_erofs_attach_page(fe, &((struct z_erofs_bvec) { .page = page, .offset = offset - map->m_la, .end = end, }), exclusive); - /* should allocate an additional short-lived page for bvset */ - if (err == -EAGAIN && !fe->candidate_bvpage) { - fe->candidate_bvpage = alloc_page(GFP_NOFS | __GFP_NOFAIL); - set_page_private(fe->candidate_bvpage, - Z_EROFS_SHORTLIVED_PAGE); - goto retry; - } - - if (err) { - DBG_BUGON(err == -EAGAIN && fe->candidate_bvpage); + if (err) goto out; - }
z_erofs_onlinepage_split(page); /* bump up the number of spiltted parts of a page */