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Message-Id: <20190730055203.28467-5-hch@lst.de>
Date: Tue, 30 Jul 2019 08:51:54 +0300
From: Christoph Hellwig <hch@....de>
To: Jérôme Glisse <jglisse@...hat.com>,
Jason Gunthorpe <jgg@...lanox.com>,
Ben Skeggs <bskeggs@...hat.com>,
Felix Kuehling <Felix.Kuehling@....com>
Cc: Ralph Campbell <rcampbell@...dia.com>, linux-mm@...ck.org,
nouveau@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
amd-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [PATCH 04/13] mm: remove the pgmap field from struct hmm_vma_walk
There is only a single place where the pgmap is passed over a function
call, so replace it with local variables in the places where we deal
with the pgmap.
Signed-off-by: Christoph Hellwig <hch@....de>
---
mm/hmm.c | 62 ++++++++++++++++++++++++--------------------------------
1 file changed, 27 insertions(+), 35 deletions(-)
diff --git a/mm/hmm.c b/mm/hmm.c
index 9a908902e4cc..d66fa29b42e0 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -278,7 +278,6 @@ EXPORT_SYMBOL(hmm_mirror_unregister);
struct hmm_vma_walk {
struct hmm_range *range;
- struct dev_pagemap *pgmap;
unsigned long last;
unsigned int flags;
};
@@ -475,6 +474,7 @@ static int hmm_vma_handle_pmd(struct mm_walk *walk,
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
+ struct dev_pagemap *pgmap = NULL;
unsigned long pfn, npages, i;
bool fault, write_fault;
uint64_t cpu_flags;
@@ -490,17 +490,14 @@ static int hmm_vma_handle_pmd(struct mm_walk *walk,
pfn = pmd_pfn(pmd) + pte_index(addr);
for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) {
if (pmd_devmap(pmd)) {
- hmm_vma_walk->pgmap = get_dev_pagemap(pfn,
- hmm_vma_walk->pgmap);
- if (unlikely(!hmm_vma_walk->pgmap))
+ pgmap = get_dev_pagemap(pfn, pgmap);
+ if (unlikely(!pgmap))
return -EBUSY;
}
pfns[i] = hmm_device_entry_from_pfn(range, pfn) | cpu_flags;
}
- if (hmm_vma_walk->pgmap) {
- put_dev_pagemap(hmm_vma_walk->pgmap);
- hmm_vma_walk->pgmap = NULL;
- }
+ if (pgmap)
+ put_dev_pagemap(pgmap);
hmm_vma_walk->last = end;
return 0;
#else
@@ -520,7 +517,7 @@ static inline uint64_t pte_to_hmm_pfn_flags(struct hmm_range *range, pte_t pte)
static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
unsigned long end, pmd_t *pmdp, pte_t *ptep,
- uint64_t *pfn)
+ uint64_t *pfn, struct dev_pagemap **pgmap)
{
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
@@ -591,9 +588,8 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
goto fault;
if (pte_devmap(pte)) {
- hmm_vma_walk->pgmap = get_dev_pagemap(pte_pfn(pte),
- hmm_vma_walk->pgmap);
- if (unlikely(!hmm_vma_walk->pgmap))
+ *pgmap = get_dev_pagemap(pte_pfn(pte), *pgmap);
+ if (unlikely(!*pgmap))
return -EBUSY;
} else if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) && pte_special(pte)) {
*pfn = range->values[HMM_PFN_SPECIAL];
@@ -604,10 +600,10 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
return 0;
fault:
- if (hmm_vma_walk->pgmap) {
- put_dev_pagemap(hmm_vma_walk->pgmap);
- hmm_vma_walk->pgmap = NULL;
- }
+ if (*pgmap)
+ put_dev_pagemap(*pgmap);
+ *pgmap = NULL;
+
pte_unmap(ptep);
/* Fault any virtual address we were asked to fault */
return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk);
@@ -620,6 +616,7 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp,
{
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
+ struct dev_pagemap *pgmap = NULL;
uint64_t *pfns = range->pfns;
unsigned long addr = start, i;
pte_t *ptep;
@@ -683,23 +680,21 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp,
for (; addr < end; addr += PAGE_SIZE, ptep++, i++) {
int r;
- r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, &pfns[i]);
+ r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, &pfns[i],
+ &pgmap);
if (r) {
/* hmm_vma_handle_pte() did unmap pte directory */
hmm_vma_walk->last = addr;
return r;
}
}
- if (hmm_vma_walk->pgmap) {
- /*
- * We do put_dev_pagemap() here and not in hmm_vma_handle_pte()
- * so that we can leverage get_dev_pagemap() optimization which
- * will not re-take a reference on a pgmap if we already have
- * one.
- */
- put_dev_pagemap(hmm_vma_walk->pgmap);
- hmm_vma_walk->pgmap = NULL;
- }
+ /*
+ * We do put_dev_pagemap() here and not in hmm_vma_handle_pte() so that
+ * we can leverage the get_dev_pagemap() optimization which will not
+ * re-take a reference on a pgmap if we already have one.
+ */
+ if (pgmap)
+ put_dev_pagemap(pgmap);
pte_unmap(ptep - 1);
hmm_vma_walk->last = addr;
@@ -714,6 +709,7 @@ static int hmm_vma_walk_pud(pud_t *pudp,
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
unsigned long addr = start, next;
+ struct dev_pagemap *pgmap = NULL;
pmd_t *pmdp;
pud_t pud;
int ret;
@@ -744,17 +740,14 @@ static int hmm_vma_walk_pud(pud_t *pudp,
pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
for (i = 0; i < npages; ++i, ++pfn) {
- hmm_vma_walk->pgmap = get_dev_pagemap(pfn,
- hmm_vma_walk->pgmap);
- if (unlikely(!hmm_vma_walk->pgmap))
+ pgmap = get_dev_pagemap(pfn, pgmap);
+ if (unlikely(!pgmap))
return -EBUSY;
pfns[i] = hmm_device_entry_from_pfn(range, pfn) |
cpu_flags;
}
- if (hmm_vma_walk->pgmap) {
- put_dev_pagemap(hmm_vma_walk->pgmap);
- hmm_vma_walk->pgmap = NULL;
- }
+ if (pgmap)
+ put_dev_pagemap(pgmap);
hmm_vma_walk->last = end;
return 0;
}
@@ -1002,7 +995,6 @@ long hmm_range_fault(struct hmm_range *range, unsigned int flags)
return -EPERM;
}
- hmm_vma_walk.pgmap = NULL;
hmm_vma_walk.last = start;
hmm_vma_walk.flags = flags;
hmm_vma_walk.range = range;
--
2.20.1
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