From f5678e7f2ac31c270334b936352f0ef2fe7dd2b3 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 10 Jun 2020 18:42:06 -0700 Subject: kernel: better document the use_mm/unuse_mm API contract Switch the function documentation to kerneldoc comments, and add WARN_ON_ONCE asserts that the calling thread is a kernel thread and does not have ->mm set (or has ->mm set in the case of unuse_mm). Also give the functions a kthread_ prefix to better document the use case. [hch@lst.de: fix a comment typo, cover the newly merged use_mm/unuse_mm caller in vfio] Link: http://lkml.kernel.org/r/20200416053158.586887-3-hch@lst.de [sfr@canb.auug.org.au: powerpc/vas: fix up for {un}use_mm() rename] Link: http://lkml.kernel.org/r/20200422163935.5aa93ba5@canb.auug.org.au Signed-off-by: Christoph Hellwig Signed-off-by: Stephen Rothwell Signed-off-by: Andrew Morton Tested-by: Jens Axboe Reviewed-by: Jens Axboe Acked-by: Felix Kuehling Acked-by: Greg Kroah-Hartman [usb] Acked-by: Haren Myneni Cc: Alex Deucher Cc: Al Viro Cc: Felipe Balbi Cc: Jason Wang Cc: "Michael S. Tsirkin" Cc: Zhenyu Wang Cc: Zhi Wang Link: http://lkml.kernel.org/r/20200404094101.672954-6-hch@lst.de Signed-off-by: Linus Torvalds --- drivers/vfio/vfio_iommu_type1.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/vfio/vfio_iommu_type1.c') diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index d5c08a750441..5e556ac9102a 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -2817,7 +2817,7 @@ static int vfio_iommu_type1_dma_rw_chunk(struct vfio_iommu *iommu, return -EPERM; if (kthread) - use_mm(mm); + kthread_use_mm(mm); else if (current->mm != mm) goto out; @@ -2844,7 +2844,7 @@ static int vfio_iommu_type1_dma_rw_chunk(struct vfio_iommu *iommu, *copied = copy_from_user(data, (void __user *)vaddr, count) ? 0 : count; if (kthread) - unuse_mm(mm); + kthread_unuse_mm(mm); out: mmput(mm); return *copied ? 0 : -EFAULT; -- cgit v1.2.3