diff options
| author | Andreas Gruenbacher <agruenba@redhat.com> | 2022-04-15 06:28:51 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-05-01 17:22:32 +0200 |
| commit | 6e213bc61446d5aefcedb00251c275e30ce82ab5 (patch) | |
| tree | 1ef9c3317256185048cf8d776abee06ce2c5d630 /mm | |
| parent | d3b744791bf06bc9720bfa36bc1757f25802d68b (diff) | |
gup: Introduce FOLL_NOFAULT flag to disable page faults
commit 55b8fe703bc51200d4698596c90813453b35ae63 upstream
Introduce a new FOLL_NOFAULT flag that causes get_user_pages to return
-EFAULT when it would otherwise trigger a page fault. This is roughly
similar to FOLL_FAST_ONLY but available on all architectures, and less
fragile.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/gup.c | 4 |
1 files changed, 3 insertions, 1 deletions
@@ -943,6 +943,8 @@ static int faultin_page(struct vm_area_struct *vma, /* mlock all present pages, but do not fault in new pages */ if ((*flags & (FOLL_POPULATE | FOLL_MLOCK)) == FOLL_MLOCK) return -ENOENT; + if (*flags & FOLL_NOFAULT) + return -EFAULT; if (*flags & FOLL_WRITE) fault_flags |= FAULT_FLAG_WRITE; if (*flags & FOLL_REMOTE) @@ -2868,7 +2870,7 @@ static int internal_get_user_pages_fast(unsigned long start, if (WARN_ON_ONCE(gup_flags & ~(FOLL_WRITE | FOLL_LONGTERM | FOLL_FORCE | FOLL_PIN | FOLL_GET | - FOLL_FAST_ONLY))) + FOLL_FAST_ONLY | FOLL_NOFAULT))) return -EINVAL; if (gup_flags & FOLL_PIN) |