| Message ID | 20190730055203.28467-12-hch@lst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [01/13] amdgpu: remove -EAGAIN handling for hmm_range_fault | expand |
On Tue, Jul 30, 2019 at 08:52:01AM +0300, Christoph Hellwig wrote: > Stub out the whole function when CONFIG_TRANSPARENT_HUGEPAGE is not set > to make the function easier to read. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > mm/hmm.c | 18 +++++++++--------- > 1 file changed, 9 insertions(+), 9 deletions(-) > > diff --git a/mm/hmm.c b/mm/hmm.c > index 4d3bd41b6522..f4e90ea5779f 100644 > +++ b/mm/hmm.c > @@ -455,13 +455,10 @@ static inline uint64_t pmd_to_hmm_pfn_flags(struct hmm_range *range, pmd_t pmd) > range->flags[HMM_PFN_VALID]; > } > > -static int hmm_vma_handle_pmd(struct mm_walk *walk, > - unsigned long addr, > - unsigned long end, > - uint64_t *pfns, > - pmd_t pmd) > -{ > #ifdef CONFIG_TRANSPARENT_HUGEPAGE > +static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr, > + unsigned long end, uint64_t *pfns, pmd_t pmd) > +{ > struct hmm_vma_walk *hmm_vma_walk = walk->private; > struct hmm_range *range = hmm_vma_walk->range; > struct dev_pagemap *pgmap = NULL; > @@ -490,11 +487,14 @@ static int hmm_vma_handle_pmd(struct mm_walk *walk, > put_dev_pagemap(pgmap); > hmm_vma_walk->last = end; > return 0; > -#else > - /* If THP is not enabled then we should never reach this This old comment says we should never get here > +} > +#else /* CONFIG_TRANSPARENT_HUGEPAGE */ > +static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr, > + unsigned long end, uint64_t *pfns, pmd_t pmd) > +{ > return -EINVAL; So could we just do #define hmm_vma_handle_pmd NULL ? At the very least this seems like a WARN_ON too? Jason
On Tue, Jul 30, 2019 at 05:53:14PM +0000, Jason Gunthorpe wrote: > > - /* If THP is not enabled then we should never reach this > > This old comment says we should never get here > > > +} > > +#else /* CONFIG_TRANSPARENT_HUGEPAGE */ > > +static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr, > > + unsigned long end, uint64_t *pfns, pmd_t pmd) > > +{ > > return -EINVAL; > > So could we just do > #define hmm_vma_handle_pmd NULL > > ? > > At the very least this seems like a WARN_ON too? Despite the name of the function hmm_vma_handle_pmd is not a callback for the pagewalk, but actually called from hmm_vma_handle_pmd. What we could try is just and empty non-inline prototype without an actual implementation, which means if the compiler doesn't optimize the calls away we'll get a link error.
diff --git a/mm/hmm.c b/mm/hmm.c index 4d3bd41b6522..f4e90ea5779f 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -455,13 +455,10 @@ static inline uint64_t pmd_to_hmm_pfn_flags(struct hmm_range *range, pmd_t pmd) range->flags[HMM_PFN_VALID]; } -static int hmm_vma_handle_pmd(struct mm_walk *walk, - unsigned long addr, - unsigned long end, - uint64_t *pfns, - pmd_t pmd) -{ #ifdef CONFIG_TRANSPARENT_HUGEPAGE +static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr, + unsigned long end, uint64_t *pfns, pmd_t pmd) +{ struct hmm_vma_walk *hmm_vma_walk = walk->private; struct hmm_range *range = hmm_vma_walk->range; struct dev_pagemap *pgmap = NULL; @@ -490,11 +487,14 @@ static int hmm_vma_handle_pmd(struct mm_walk *walk, put_dev_pagemap(pgmap); hmm_vma_walk->last = end; return 0; -#else - /* If THP is not enabled then we should never reach this code ! */ +} +#else /* CONFIG_TRANSPARENT_HUGEPAGE */ +static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr, + unsigned long end, uint64_t *pfns, pmd_t pmd) +{ return -EINVAL; -#endif } +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ static inline uint64_t pte_to_hmm_pfn_flags(struct hmm_range *range, pte_t pte) {
Stub out the whole function when CONFIG_TRANSPARENT_HUGEPAGE is not set to make the function easier to read. Signed-off-by: Christoph Hellwig <hch@lst.de> --- mm/hmm.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)