The quilt patch titled Subject: mm-gup-stop-leaking-pinned-pages-in-low-memory-conditions-v3 has been removed from the -mm tree. Its filename was mm-gup-stop-leaking-pinned-pages-in-low-memory-conditions-v3.patch This patch was dropped because it was folded into mm-gup-stop-leaking-pinned-pages-in-low-memory-conditions.patch ------------------------------------------------------ From: John Hubbard <jhubbard@xxxxxxxxxx> Subject: mm-gup-stop-leaking-pinned-pages-in-low-memory-conditions-v3 Date: Fri, 18 Oct 2024 15:34:11 -0700 1) Applied the fix to check_and_migrate_movable_pages(), instead of its caller, as per David Hildenbrand's suggestion (thanks!). 2) Dropped Alistair's reviewed-by tag, because the fix has changed. 3) Reworked the relevant documentation, and commit description. Link: https://lkml.kernel.org/r/20241018223411.310331-1-jhubbard@xxxxxxxxxx Fixes: 24a95998e9ba ("mm/gup.c: simplify and fix check_and_migrate_movable_pages() return codes") Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx> Suggested-by: David Hildenbrand <david@xxxxxxxxxx> Cc: Alistair Popple <apopple@xxxxxxxxxx> Cc: Shigeru Yoshida <syoshida@xxxxxxxxxx> Cc: Jason Gunthorpe <jgg@xxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> Cc: Dave Airlie <airlied@xxxxxxxxxx> Cc: Dongwon Kim <dongwon.kim@xxxxxxxxx> Cc: Gerd Hoffmann <kraxel@xxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Junxiao Chang <junxiao.chang@xxxxxxxxx> Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Cc: Oscar Salvador <osalvador@xxxxxxx> Cc: Peter Xu <peterx@xxxxxxxxxx> Cc: Vivek Kasireddy <vivek.kasireddy@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/gup.c | 33 +++++++++++++++++++-------------- 1 file changed, 19 insertions(+), 14 deletions(-) --- a/mm/gup.c~mm-gup-stop-leaking-pinned-pages-in-low-memory-conditions-v3 +++ a/mm/gup.c @@ -2394,20 +2394,25 @@ err: } /* - * Check whether all folios are *allowed* to be pinned indefinitely (longterm). + * Check whether all folios are *allowed* to be pinned indefinitely (long term). * Rather confusingly, all folios in the range are required to be pinned via * FOLL_PIN, before calling this routine. * - * If any folios in the range are not allowed to be pinned, then this routine - * will migrate those folios away, unpin all the folios in the range and return - * -EAGAIN. The caller should re-pin the entire range with FOLL_PIN and then - * call this routine again. + * Return values: * - * If an error other than -EAGAIN occurs, this indicates a migration failure. - * The caller should give up, and propagate the error back up the call stack. - * - * If everything is OK and all folios in the range are allowed to be pinned, + * 0: if everything is OK and all folios in the range are allowed to be pinned, * then this routine leaves all folios pinned and returns zero for success. + * + * -EAGAIN: if any folios in the range are not allowed to be pinned, then this + * routine will migrate those folios away, unpin all the folios in the range. If + * migration of the entire set of folios succeeds, then -EAGAIN is returned. The + * caller should re-pin the entire range with FOLL_PIN and then call this + * routine again. + * + * -ENOMEM, or any other -errno: if an error *other* than -EAGAIN occurs, this + * indicates a migration failure. The caller should give up, and propagate the + * error back up the call stack. The caller does not need to unpin any folios in + * that case, because this routine will do the unpinning. */ static long check_and_migrate_movable_folios(unsigned long nr_folios, struct folio **folios) @@ -2425,10 +2430,8 @@ static long check_and_migrate_movable_fo } /* - * This routine just converts all the pages in the @pages array to folios and - * calls check_and_migrate_movable_folios() to do the heavy lifting. - * - * Please see the check_and_migrate_movable_folios() documentation for details. + * Return values and behavior are the same as those for + * check_and_migrate_movable_folios(). */ static long check_and_migrate_movable_pages(unsigned long nr_pages, struct page **pages) @@ -2437,8 +2440,10 @@ static long check_and_migrate_movable_pa long i, ret; folios = kmalloc_array(nr_pages, sizeof(*folios), GFP_KERNEL); - if (!folios) + if (!folios) { + unpin_user_pages(pages, nr_pages); return -ENOMEM; + } for (i = 0; i < nr_pages; i++) folios[i] = page_folio(pages[i]); _ Patches currently in -mm which might be from jhubbard@xxxxxxxxxx are mm-gup-stop-leaking-pinned-pages-in-low-memory-conditions.patch mm-gup-memfd-stop-leaking-pinned-pages-in-low-memory-conditions.patch kaslr-rename-physmem_end-and-physmem_end-to-direct_map_physmem_end.patch