| Message ID | 1e2824fd77e8eeb351c6c6246f384d0d89fd2d58.1553093421.git.andreyknvl@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: untag user pointers passed to the kernel | expand |
On Wed, Mar 20, 2019 at 03:51:30PM +0100, Andrey Konovalov wrote: > This patch is a part of a series that extends arm64 kernel ABI to allow to > pass tagged user pointers (with the top byte set to something else other > than 0x00) as syscall arguments. > > mlx4_get_umem_mr() uses provided user pointers for vma lookups, which can > only by done with untagged pointers. > > Untag user pointers in this function. > > Signed-off-by: Andrey Konovalov <andreyknvl@google.com> > --- > drivers/infiniband/hw/mlx4/mr.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/infiniband/hw/mlx4/mr.c b/drivers/infiniband/hw/mlx4/mr.c > index 395379a480cb..9a35ed2c6a6f 100644 > --- a/drivers/infiniband/hw/mlx4/mr.c > +++ b/drivers/infiniband/hw/mlx4/mr.c > @@ -378,6 +378,7 @@ static struct ib_umem *mlx4_get_umem_mr(struct ib_udata *udata, u64 start, > * again > */ > if (!ib_access_writable(access_flags)) { > + unsigned long untagged_start = untagged_addr(start); > struct vm_area_struct *vma; > > down_read(¤t->mm->mmap_sem); > @@ -386,9 +387,9 @@ static struct ib_umem *mlx4_get_umem_mr(struct ib_udata *udata, u64 start, > * cover the memory, but for now it requires a single vma to > * entirely cover the MR to support RO mappings. > */ > - vma = find_vma(current->mm, start); > - if (vma && vma->vm_end >= start + length && > - vma->vm_start <= start) { > + vma = find_vma(current->mm, untagged_start); > + if (vma && vma->vm_end >= untagged_start + length && > + vma->vm_start <= untagged_start) { > if (vma->vm_flags & VM_WRITE) > access_flags |= IB_ACCESS_LOCAL_WRITE; > } else { > -- Thanks, Reviewed-by: Leon Romanovsky <leonro@mellanox.com> Interesting, the followup question is why mlx4 is only one driver in IB which needs such code in umem_mr. I'll take a look on it. Thanks
diff --git a/drivers/infiniband/hw/mlx4/mr.c b/drivers/infiniband/hw/mlx4/mr.c index 395379a480cb..9a35ed2c6a6f 100644 --- a/drivers/infiniband/hw/mlx4/mr.c +++ b/drivers/infiniband/hw/mlx4/mr.c @@ -378,6 +378,7 @@ static struct ib_umem *mlx4_get_umem_mr(struct ib_udata *udata, u64 start, * again */ if (!ib_access_writable(access_flags)) { + unsigned long untagged_start = untagged_addr(start); struct vm_area_struct *vma; down_read(¤t->mm->mmap_sem); @@ -386,9 +387,9 @@ static struct ib_umem *mlx4_get_umem_mr(struct ib_udata *udata, u64 start, * cover the memory, but for now it requires a single vma to * entirely cover the MR to support RO mappings. */ - vma = find_vma(current->mm, start); - if (vma && vma->vm_end >= start + length && - vma->vm_start <= start) { + vma = find_vma(current->mm, untagged_start); + if (vma && vma->vm_end >= untagged_start + length && + vma->vm_start <= untagged_start) { if (vma->vm_flags & VM_WRITE) access_flags |= IB_ACCESS_LOCAL_WRITE; } else {
This patch is a part of a series that extends arm64 kernel ABI to allow to pass tagged user pointers (with the top byte set to something else other than 0x00) as syscall arguments. mlx4_get_umem_mr() uses provided user pointers for vma lookups, which can only by done with untagged pointers. Untag user pointers in this function. Signed-off-by: Andrey Konovalov <andreyknvl@google.com> --- drivers/infiniband/hw/mlx4/mr.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)