| Message ID | 20200311183506.3997-6-jgg@ziepe.ca (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Various error case bug fixes for hmm_range_fault() | expand |
On 3/11/20 11:35 AM, Jason Gunthorpe wrote: > From: Jason Gunthorpe <jgg@mellanox.com> > > All return paths that do EFAULT must call hmm_range_need_fault() to > determine if the user requires this page to be valid. > > If the page cannot be made valid if the user later requires it, due to vma > flags in this case, then the return should be HMM_PFN_ERROR. > > Fixes: a3e0d41c2b1f ("mm/hmm: improve driver API to work and wait over a range") > Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> > --- > mm/hmm.c | 19 ++++++++----------- > 1 file changed, 8 insertions(+), 11 deletions(-) > > diff --git a/mm/hmm.c b/mm/hmm.c > index 5f5ccf13dd1e85..e10cd0adba7b37 100644 > --- a/mm/hmm.c > +++ b/mm/hmm.c > @@ -582,18 +582,15 @@ static int hmm_vma_walk_test(unsigned long start, unsigned long end, > struct vm_area_struct *vma = walk->vma; > > /* > - * Skip vma ranges that don't have struct page backing them or > - * map I/O devices directly. > - */ > - if (vma->vm_flags & (VM_IO | VM_PFNMAP | VM_MIXEDMAP)) > - return -EFAULT; > - > - /* > + * Skip vma ranges that don't have struct page backing them or map I/O > + * devices directly. > + * > * If the vma does not allow read access, then assume that it does not > - * allow write access either. HMM does not support architectures > - * that allow write without read. > + * allow write access either. HMM does not support architectures that > + * allow write without read. > */ > - if (!(vma->vm_flags & VM_READ)) { > + if ((vma->vm_flags & (VM_IO | VM_PFNMAP | VM_MIXEDMAP)) || > + !(vma->vm_flags & VM_READ)) { > bool fault, write_fault; > > /* > @@ -607,7 +604,7 @@ static int hmm_vma_walk_test(unsigned long start, unsigned long end, > if (fault || write_fault) > return -EFAULT; > > - hmm_pfns_fill(start, end, range, HMM_PFN_NONE); > + hmm_pfns_fill(start, end, range, HMM_PFN_ERROR); > hmm_vma_walk->last = end; > > /* Skip this vma and continue processing the next vma. */ >
On Wed, Mar 11, 2020 at 03:35:03PM -0300, Jason Gunthorpe wrote: > From: Jason Gunthorpe <jgg@mellanox.com> > > All return paths that do EFAULT must call hmm_range_need_fault() to > determine if the user requires this page to be valid. > > If the page cannot be made valid if the user later requires it, due to vma > flags in this case, then the return should be HMM_PFN_ERROR. > > Fixes: a3e0d41c2b1f ("mm/hmm: improve driver API to work and wait over a range") > Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> Looks good, Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/mm/hmm.c b/mm/hmm.c index 5f5ccf13dd1e85..e10cd0adba7b37 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -582,18 +582,15 @@ static int hmm_vma_walk_test(unsigned long start, unsigned long end, struct vm_area_struct *vma = walk->vma; /* - * Skip vma ranges that don't have struct page backing them or - * map I/O devices directly. - */ - if (vma->vm_flags & (VM_IO | VM_PFNMAP | VM_MIXEDMAP)) - return -EFAULT; - - /* + * Skip vma ranges that don't have struct page backing them or map I/O + * devices directly. + * * If the vma does not allow read access, then assume that it does not - * allow write access either. HMM does not support architectures - * that allow write without read. + * allow write access either. HMM does not support architectures that + * allow write without read. */ - if (!(vma->vm_flags & VM_READ)) { + if ((vma->vm_flags & (VM_IO | VM_PFNMAP | VM_MIXEDMAP)) || + !(vma->vm_flags & VM_READ)) { bool fault, write_fault; /* @@ -607,7 +604,7 @@ static int hmm_vma_walk_test(unsigned long start, unsigned long end, if (fault || write_fault) return -EFAULT; - hmm_pfns_fill(start, end, range, HMM_PFN_NONE); + hmm_pfns_fill(start, end, range, HMM_PFN_ERROR); hmm_vma_walk->last = end; /* Skip this vma and continue processing the next vma. */