On Wed, May 22, 2019 at 01:23:22PM -0700, Andrew Morton wrote:
> On Wed, 22 May 2019 19:51:55 +0000 Jason Gunthorpe <jgg@xxxxxxxxxxxx> wrote:
>
> > gcc reports that several variables are defined but not used.
> >
> > For the first hunk CONFIG_HUGETLB_PAGE the entire if block is already
> > protected by pud_huge() which is forced to 0. None of the stuff under
> > the ifdef causes compilation problems as it is already stubbed out in
> > the header files.
> >
> > For the second hunk the dummy huge_page_shift macro doesn't touch the
> > argument, so just inline the argument.
> >
> > ...
> >
> > +++ b/mm/hmm.c
> > @@ -797,7 +797,6 @@ static int hmm_vma_walk_pud(pud_t *pudp,
> > return hmm_vma_walk_hole_(addr, end, fault,
> > write_fault, walk);
> >
> > -#ifdef CONFIG_HUGETLB_PAGE
> > pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
> > for (i = 0; i < npages; ++i, ++pfn) {
> > hmm_vma_walk->pgmap = get_dev_pagemap(pfn,
> > @@ -813,9 +812,6 @@ static int hmm_vma_walk_pud(pud_t *pudp,
> > }
> > hmm_vma_walk->last = end;
> > return 0;
> > -#else
> > - return -EINVAL;
> > -#endif
> > }
>
> Fair enough.
>
> > split_huge_pud(walk->vma, pudp, addr);
> > @@ -1024,9 +1020,8 @@ long hmm_range_snapshot(struct hmm_range *range)
> > return -EFAULT;
> >
> > if (is_vm_hugetlb_page(vma)) {
> > - struct hstate *h = hstate_vma(vma);
> > -
> > - if (huge_page_shift(h) != range->page_shift &&
> > + if (huge_page_shift(hstate_vma(vma)) !=
> > + range->page_shift &&
> > range->page_shift != PAGE_SHIFT)
> > return -EINVAL;
>
> Also fair enough. But why the heck is huge_page_shift() a macro? We
> keep doing that and it bites so often :(
Let's fix it, with the below? (compile tested)
Note __alloc_bootmem_huge_page was returning null but the signature
was unsigned int.
>From b5e2ff3c88e6962d0e8297c87af855e6fe1a584e Mon Sep 17 00:00:00 2001
From: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Date: Wed, 22 May 2019 20:45:59 -0300
Subject: [PATCH] mm: Make !CONFIG_HUGE_PAGE wrappers into static inlines
Instead of using defines, which looses type safety and provokes unused
variable warnings from gcc, put the constants into static inlines.
Suggested-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
---
include/linux/hugetlb.h | 102 +++++++++++++++++++++++++++++++++-------
1 file changed, 86 insertions(+), 16 deletions(-)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index edf476c8cfb9c0..f895a79c6f5cb4 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -608,22 +608,92 @@ static inline void huge_ptep_modify_prot_commit(struct vm_area_struct *vma,
#else /* CONFIG_HUGETLB_PAGE */
struct hstate {};
-#define alloc_huge_page(v, a, r) NULL
-#define alloc_huge_page_node(h, nid) NULL
-#define alloc_huge_page_nodemask(h, preferred_nid, nmask) NULL
-#define alloc_huge_page_vma(h, vma, address) NULL
-#define alloc_bootmem_huge_page(h) NULL
-#define hstate_file(f) NULL
-#define hstate_sizelog(s) NULL
-#define hstate_vma(v) NULL
-#define hstate_inode(i) NULL
-#define page_hstate(page) NULL
-#define huge_page_size(h) PAGE_SIZE
-#define huge_page_mask(h) PAGE_MASK
-#define vma_kernel_pagesize(v) PAGE_SIZE
-#define vma_mmu_pagesize(v) PAGE_SIZE
-#define huge_page_order(h) 0
-#define huge_page_shift(h) PAGE_SHIFT
+
+static inline struct page *alloc_huge_page(struct vm_area_struct *vma,
+ unsigned long addr,
+ int avoid_reserve)
+{
+ return NULL;
+}
+
+static inline struct page *alloc_huge_page_node(struct hstate *h, int nid)
+{
+ return NULL;
+}
+
+static inline struct page *
+alloc_huge_page_nodemask(struct hstate *h, int preferred_nid, nodemask_t *nmask)
+{
+ return NULL;
+}
+
+static inline struct page *alloc_huge_page_vma(struct hstate *h,
+ struct vm_area_struct *vma,
+ unsigned long address)
+{
+ return NULL;
+}
+
+static inline int __alloc_bootmem_huge_page(struct hstate *h)
+{
+ return 0;
+}
+
+static inline struct hstate *hstate_file(struct file *f)
+{
+ return NULL;
+}
+
+static inline struct hstate *hstate_sizelog(int page_size_log)
+{
+ return NULL;
+}
+
+static inline struct hstate *hstate_vma(struct vm_area_struct *vma)
+{
+ return NULL;
+}
+
+static inline struct hstate *hstate_inode(struct inode *i)
+{
+ return NULL;
+}
+
+static inline struct hstate *page_hstate(struct page *page)
+{
+ return NULL;
+}
+
+static inline unsigned long huge_page_size(struct hstate *h)
+{
+ return PAGE_SIZE;
+}
+
+static inline unsigned long huge_page_mask(struct hstate *h)
+{
+ return PAGE_MASK;
+}
+
+static inline unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
+{
+ return PAGE_SIZE;
+}
+
+static inline unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
+{
+ return PAGE_SIZE;
+}
+
+static inline unsigned int huge_page_order(struct hstate *h)
+{
+ return 0;
+}
+
+static inline unsigned int huge_page_shift(struct hstate *h)
+{
+ return PAGE_SHIFT;
+}
+
static inline bool hstate_is_gigantic(struct hstate *h)
{
return false;
--
2.21.0
