From: Andrea Arcangeli <aarcange@xxxxxxxxxx> Subject: userfaultfd: provide pid in userfault msg - add feat union No ABI change, but this will make it more explicit to software that ptid is only available if requested by passing UFFD_FEATURE_THREAD_ID to UFFDIO_API. The fact it's a union will also self document it shouldn't be taken for granted there's a tpid there. Link: http://lkml.kernel.org/r/20170802165145.22628-7-aarcange@xxxxxxxxxx Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: "Dr. David Alan Gilbert" <dgilbert@xxxxxxxxxx> Cc: Alexey Perevalov <a.perevalov@xxxxxxxxxxx> Cc: Maxime Coquelin <maxime.coquelin@xxxxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/userfaultfd.c | 2 +- include/uapi/linux/userfaultfd.h | 4 +++- 2 files changed, 4 insertions(+), 2 deletions(-) diff -puN fs/userfaultfd.c~userfaultfd-provide-pid-in-userfault-msg-add-feat-union fs/userfaultfd.c --- a/fs/userfaultfd.c~userfaultfd-provide-pid-in-userfault-msg-add-feat-union +++ a/fs/userfaultfd.c @@ -204,7 +204,7 @@ static inline struct uffd_msg userfault_ */ msg.arg.pagefault.flags |= UFFD_PAGEFAULT_FLAG_WP; if (features & UFFD_FEATURE_THREAD_ID) - msg.arg.pagefault.ptid = task_pid_vnr(current); + msg.arg.pagefault.feat.ptid = task_pid_vnr(current); return msg; } diff -puN include/uapi/linux/userfaultfd.h~userfaultfd-provide-pid-in-userfault-msg-add-feat-union include/uapi/linux/userfaultfd.h --- a/include/uapi/linux/userfaultfd.h~userfaultfd-provide-pid-in-userfault-msg-add-feat-union +++ a/include/uapi/linux/userfaultfd.h @@ -80,7 +80,9 @@ struct uffd_msg { struct { __u64 flags; __u64 address; - __u32 ptid; + union { + __u32 ptid; + } feat; } pagefault; struct { _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
