lkml.org 
[lkml]   [2021]   [Nov]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH] vdpa: Consider device id larger than 31
    On Sun, Nov 28, 2021 at 09:14:35AM +0200, Eli Cohen wrote:
    > On Fri, Nov 26, 2021 at 10:48:12AM +0800, Jason Wang wrote:
    > > On Fri, Nov 26, 2021 at 2:09 AM Parav Pandit <parav@nvidia.com> wrote:
    > > >
    > > > virtio device id value can be more than 31. Hence, use BIT_ULL in
    > > > assignment.
    > > >
    > > > Fixes: 33b347503f01 ("vdpa: Define vdpa mgmt device, ops and a netlink interface")
    > > > Reported-by: kernel test robot <lkp@intel.com>
    > > > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
    > > > Signed-off-by: Parav Pandit <parav@nvidia.com>
    > >
    > > Acked-by: Jason Wang <jasowang@redhat.com>
    > >
    > > > ---
    > > > drivers/vdpa/vdpa.c | 2 +-
    > > > 1 file changed, 1 insertion(+), 1 deletion(-)
    > > >
    > > > diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
    > > > index 7332a74a4b00..e91c71aeeddf 100644
    > > > --- a/drivers/vdpa/vdpa.c
    > > > +++ b/drivers/vdpa/vdpa.c
    > > > @@ -404,7 +404,7 @@ static int vdpa_mgmtdev_fill(const struct vdpa_mgmt_dev *mdev, struct sk_buff *m
    > > > goto msg_err;
    > > >
    > > > while (mdev->id_table[i].device) {
    > > > - supported_classes |= BIT(mdev->id_table[i].device);
    > > > + supported_classes |= BIT_ULL(mdev->id_table[i].device);
    > > > i++;
    > > > }
    > > >
    >
    > type of mdev->id_table[i].device is __u32 so in theory you're limited
    > to device ID's up to 63.

    A u32 can fit numbers up to 4 million? These .device numbers are
    normally hardcoded defines listed in usr/include/linux/virtio_ids.h

    But sometimes they're not like in vp_modern_probe() which does:

    mdev->id.device = pci_dev->device - 0x1040;

    I don't know if an assert is really worth it, considering how almost all
    of them are hardcoded. Also if we do want an assert maybe there is a
    better place to put it?

    regards,
    dan carpenter

    \
     
     \ /
      Last update: 2021-11-29 08:02    [W:3.156 / U:0.080 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site