From ecc53f8a3c097d13f4b6793855e0bd30a63a5c3a Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Tue, 23 Jul 2019 19:58:48 +0200 Subject: [PATCH] RDMA/mlx4: Untag user pointers in mlx4_get_umem_mr This patch is a part of a series that extends 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. Link: https://lore.kernel.org/r/7969018013a67ddbbf784ac7afeea5a57b1e2bcb.1563904656.git.andreyknvl@google.com Reviewed-by: Jason Gunthorpe Acked-by: Catalin Marinas Reviewed-by: Kees Cook Signed-off-by: Andrey Konovalov Signed-off-by: Jason Gunthorpe --- 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 753479285ce92..6ae503cfc5264 100644 --- a/drivers/infiniband/hw/mlx4/mr.c +++ b/drivers/infiniband/hw/mlx4/mr.c @@ -377,6 +377,7 @@ 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); @@ -385,9 +386,9 @@ 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 { -- 2.30.2