Messages in this thread | | | From | Mike Kravetz <> | Subject | [PATCH 0/1] fix page_cache_next/prev_miss off by one error | Date | Thu, 4 May 2023 16:38:57 -0700 |
| |
A cover letter is not necessary for this single patch as all information is present in the commit message. However, I am not 100% comfortable in this change and would REALLY like to get comments from Matthew.
When reporting this issue, Ackerley Tng suggested a solution by creating a new filemap_has_folio() function[1]. I believe that would be an acceptable way to proceed although we would also need to change the other use of page_cache_next_miss in hugetlb.c.
When looking more closely, it looks like page_cache_next/prev_miss do not work exactly as described. The result is the following patch.
IIUC, prior to hugetlb use of page_cache_next/prev_miss, it was only used by readahead code. My patch does change the return value and has potential to impact the readahead users. That is why I am not 100% comfortable with this.
In any case, this is broken in v6.3 so we need a fix.
[1] https://lore.kernel.org/linux-mm/cover.1683069252.git.ackerleytng@google.com/ Mike Kravetz (1): page cache: fix page_cache_next/prev_miss off by one
mm/filemap.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-)
-- 2.40.0
| |