With locked_vm now an atomic, there is no need to take mmap_sem as writer. Delete and refactor accordingly.
Signed-off-by: Daniel Jordan <[email protected]> Cc: Alex Williamson <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Christoph Lameter <[email protected]> Cc: Davidlohr Bueso <[email protected]> Cc: <[email protected]> Cc: <[email protected]> Cc: <[email protected]> --- drivers/vfio/vfio_iommu_type1.c | 27 +++++++++------------------ 1 file changed, 9 insertions(+), 18 deletions(-) diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 5b2878697286..a227de6d9c4c 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -257,7 +257,8 @@ static int vfio_iova_put_vfio_pfn(struct vfio_dma *dma, struct vfio_pfn *vpfn) static int vfio_lock_acct(struct vfio_dma *dma, long npage, bool async) { struct mm_struct *mm; - int ret; + s64 locked_vm; + int ret = 0; if (!npage) return 0; @@ -266,25 +267,15 @@ static int vfio_lock_acct(struct vfio_dma *dma, long npage, bool async) if (!mm) return -ESRCH; /* process exited */ - ret = down_write_killable(&mm->mmap_sem); - if (!ret) { - if (npage > 0) { - if (!dma->lock_cap) { - s64 locked_vm = atomic64_read(&mm->locked_vm); - unsigned long limit; - - limit = task_rlimit(dma->task, - RLIMIT_MEMLOCK) >> PAGE_SHIFT; + locked_vm = atomic64_add_return(npage, &mm->locked_vm); - if (locked_vm + npage > limit) - ret = -ENOMEM; - } + if (npage > 0 && !dma->lock_cap) { + unsigned long limit = task_rlimit(dma->task, RLIMIT_MEMLOCK) >> + PAGE_SHIFT; + if (locked_vm > limit) { + atomic64_sub(npage, &mm->locked_vm); + ret = -ENOMEM; } - - if (!ret) - atomic64_add(npage, &mm->locked_vm); - - up_write(&mm->mmap_sem); } if (async) -- 2.21.0
