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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 <jgg@mellanox.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Andrey Konovalov 2019-07-23 19:58:48 +02:00 committed by Jason Gunthorpe
parent 795130b319
commit ecc53f8a3c
1 changed files with 4 additions and 3 deletions
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7
drivers/infiniband/hw/mlx4/mr.c
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@ -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(&current->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 {