In preparation for exporting very similar functionality through another
interface, gut the current remap_pfn_range(). The motivating factor here
is to reuse the PGB/PUD/PMD/PTE walker, but allow back progation of
errors rather than BUG_ON.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
---
mm/memory.c | 102 +++++++++++++++++++++++++++++++++---------------------------
1 file changed, 57 insertions(+), 45 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index 97839f5c8c30..acb06f40d614 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1614,71 +1614,81 @@ int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
}
EXPORT_SYMBOL(vm_insert_mixed);
+struct remap_pfn {
+ struct mm_struct *mm;
+ unsigned long addr;
+ unsigned long pfn;
+ pgprot_t prot;
+};
+
/*
* maps a range of physical memory into the requested pages. the old
* mappings are removed. any references to nonexistent pages results
* in null mappings (currently treated as "copy-on-access")
*/
-static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
- unsigned long addr, unsigned long end,
- unsigned long pfn, pgprot_t prot)
+static inline int remap_pfn(struct remap_pfn *r, pte_t *pte)
+{
+ if (!pte_none(*pte))
+ return -EBUSY;
+
+ set_pte_at(r->mm, r->addr, pte,
+ pte_mkspecial(pfn_pte(r->pfn, r->prot)));
+ r->pfn++;
+ r->addr += PAGE_SIZE;
+ return 0;
+}
+
+static int remap_pte_range(struct remap_pfn *r, pmd_t *pmd, unsigned long end)
{
pte_t *pte;
spinlock_t *ptl;
+ int err;
- pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
+ pte = pte_alloc_map_lock(r->mm, pmd, r->addr, &ptl);
if (!pte)
return -ENOMEM;
+
arch_enter_lazy_mmu_mode();
do {
- BUG_ON(!pte_none(*pte));
- set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
- pfn++;
- } while (pte++, addr += PAGE_SIZE, addr != end);
+ err = remap_pfn(r, pte++);
+ } while (err == 0 && r->addr < end);
arch_leave_lazy_mmu_mode();
+
pte_unmap_unlock(pte - 1, ptl);
- return 0;
+ return err;
}
-static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
- unsigned long addr, unsigned long end,
- unsigned long pfn, pgprot_t prot)
+static inline int remap_pmd_range(struct remap_pfn *r, pud_t *pud, unsigned long end)
{
pmd_t *pmd;
- unsigned long next;
+ int err;
- pfn -= addr >> PAGE_SHIFT;
- pmd = pmd_alloc(mm, pud, addr);
+ pmd = pmd_alloc(r->mm, pud, r->addr);
if (!pmd)
return -ENOMEM;
VM_BUG_ON(pmd_trans_huge(*pmd));
+
do {
- next = pmd_addr_end(addr, end);
- if (remap_pte_range(mm, pmd, addr, next,
- pfn + (addr >> PAGE_SHIFT), prot))
- return -ENOMEM;
- } while (pmd++, addr = next, addr != end);
- return 0;
+ err = remap_pte_range(r, pmd++, pmd_addr_end(r->addr, end));
+ } while (err == 0 && r->addr < end);
+
+ return err;
}
-static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
- unsigned long addr, unsigned long end,
- unsigned long pfn, pgprot_t prot)
+static inline int remap_pud_range(struct remap_pfn *r, pgd_t *pgd, unsigned long end)
{
pud_t *pud;
- unsigned long next;
+ int err;
- pfn -= addr >> PAGE_SHIFT;
- pud = pud_alloc(mm, pgd, addr);
+ pud = pud_alloc(r->mm, pgd, r->addr);
if (!pud)
return -ENOMEM;
+
do {
- next = pud_addr_end(addr, end);
- if (remap_pmd_range(mm, pud, addr, next,
- pfn + (addr >> PAGE_SHIFT), prot))
- return -ENOMEM;
- } while (pud++, addr = next, addr != end);
- return 0;
+ err = remap_pmd_range(r, pud++, pud_addr_end(r->addr, end));
+ } while (err == 0 && r->addr < end);
+
+ return err;
}
/**
@@ -1694,10 +1704,9 @@ static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn, unsigned long size, pgprot_t prot)
{
- pgd_t *pgd;
- unsigned long next;
unsigned long end = addr + PAGE_ALIGN(size);
- struct mm_struct *mm = vma->vm_mm;
+ struct remap_pfn r;
+ pgd_t *pgd;
int err;
/*
@@ -1731,19 +1740,22 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
BUG_ON(addr >= end);
- pfn -= addr >> PAGE_SHIFT;
- pgd = pgd_offset(mm, addr);
flush_cache_range(vma, addr, end);
+
+ r.mm = vma->vm_mm;
+ r.addr = addr;
+ r.pfn = pfn;
+ r.prot = prot;
+
+ pgd = pgd_offset(r.mm, addr);
do {
- next = pgd_addr_end(addr, end);
- err = remap_pud_range(mm, pgd, addr, next,
- pfn + (addr >> PAGE_SHIFT), prot);
- if (err)
- break;
- } while (pgd++, addr = next, addr != end);
+ err = remap_pud_range(&r, pgd++, pgd_addr_end(r.addr, end));
+ } while (err == 0 && r.addr < end);
- if (err)
+ if (err) {
untrack_pfn(vma, pfn, PAGE_ALIGN(size));
+ BUG_ON(err == -EBUSY);
+ }
return err;
}
--
2.1.4
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