diff options
| -rw-r--r-- | arch/x86/mm/pat/memtype.c | 52 | ||||
| -rw-r--r-- | include/linux/pgtable.h | 28 | ||||
| -rw-r--r-- | kernel/fork.c | 4 | ||||
| -rw-r--r-- | mm/memory.c | 11 |
4 files changed, 58 insertions, 37 deletions
diff --git a/arch/x86/mm/pat/memtype.c b/arch/x86/mm/pat/memtype.c index e40861c9cb90..72d8cbc61158 100644 --- a/arch/x86/mm/pat/memtype.c +++ b/arch/x86/mm/pat/memtype.c @@ -984,29 +984,42 @@ static int get_pat_info(struct vm_area_struct *vma, resource_size_t *paddr, return -EINVAL; } -/* - * track_pfn_copy is called when vma that is covering the pfnmap gets - * copied through copy_page_range(). - * - * If the vma has a linear pfn mapping for the entire range, we get the prot - * from pte and reserve the entire vma range with single reserve_pfn_range call. - */ -int track_pfn_copy(struct vm_area_struct *vma) +int track_pfn_copy(struct vm_area_struct *dst_vma, + struct vm_area_struct *src_vma, unsigned long *pfn) { + const unsigned long vma_size = src_vma->vm_end - src_vma->vm_start; resource_size_t paddr; - unsigned long vma_size = vma->vm_end - vma->vm_start; pgprot_t pgprot; + int rc; - if (vma->vm_flags & VM_PAT) { - if (get_pat_info(vma, &paddr, &pgprot)) - return -EINVAL; - /* reserve the whole chunk covered by vma. */ - return reserve_pfn_range(paddr, vma_size, &pgprot, 1); - } + if (!(src_vma->vm_flags & VM_PAT)) + return 0; + + /* + * Duplicate the PAT information for the dst VMA based on the src + * VMA. + */ + if (get_pat_info(src_vma, &paddr, &pgprot)) + return -EINVAL; + rc = reserve_pfn_range(paddr, vma_size, &pgprot, 1); + if (rc) + return rc; + /* Reservation for the destination VMA succeeded. */ + vm_flags_set(dst_vma, VM_PAT); + *pfn = PHYS_PFN(paddr); return 0; } +void untrack_pfn_copy(struct vm_area_struct *dst_vma, unsigned long pfn) +{ + untrack_pfn(dst_vma, pfn, dst_vma->vm_end - dst_vma->vm_start, true); + /* + * Reservation was freed, any copied page tables will get cleaned + * up later, but without getting PAT involved again. + */ +} + /* * prot is passed in as a parameter for the new mapping. If the vma has * a linear pfn mapping for the entire range, or no vma is provided, @@ -1095,15 +1108,6 @@ void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn, } } -/* - * untrack_pfn_clear is called if the following situation fits: - * - * 1) while mremapping a pfnmap for a new region, with the old vma after - * its pfnmap page table has been removed. The new vma has a new pfnmap - * to the same pfn & cache type with VM_PAT set. - * 2) while duplicating vm area, the new vma fails to copy the pgtable from - * old vma. - */ void untrack_pfn_clear(struct vm_area_struct *vma) { vm_flags_clear(vma, VM_PAT); diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 94d267d02372..4c107e17c547 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -1508,15 +1508,26 @@ static inline void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot, } /* - * track_pfn_copy is called when vma that is covering the pfnmap gets - * copied through copy_page_range(). + * track_pfn_copy is called when a VM_PFNMAP VMA is about to get the page + * tables copied during copy_page_range(). On success, stores the pfn to be + * passed to untrack_pfn_copy(). */ -static inline int track_pfn_copy(struct vm_area_struct *vma) +static inline int track_pfn_copy(struct vm_area_struct *dst_vma, + struct vm_area_struct *src_vma, unsigned long *pfn) { return 0; } /* + * untrack_pfn_copy is called when a VM_PFNMAP VMA failed to copy during + * copy_page_range(), but after track_pfn_copy() was already called. + */ +static inline void untrack_pfn_copy(struct vm_area_struct *dst_vma, + unsigned long pfn) +{ +} + +/* * untrack_pfn is called while unmapping a pfnmap for a region. * untrack can be called for a specific region indicated by pfn and size or * can be for the entire vma (in which case pfn, size are zero). @@ -1528,8 +1539,10 @@ static inline void untrack_pfn(struct vm_area_struct *vma, } /* - * untrack_pfn_clear is called while mremapping a pfnmap for a new region - * or fails to copy pgtable during duplicate vm area. + * untrack_pfn_clear is called in the following cases on a VM_PFNMAP VMA: + * + * 1) During mremap() on the src VMA after the page tables were moved. + * 2) During fork() on the dst VMA, immediately after duplicating the src VMA. */ static inline void untrack_pfn_clear(struct vm_area_struct *vma) { @@ -1540,7 +1553,10 @@ extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot, unsigned long size); extern void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot, pfn_t pfn); -extern int track_pfn_copy(struct vm_area_struct *vma); +extern int track_pfn_copy(struct vm_area_struct *dst_vma, + struct vm_area_struct *src_vma, unsigned long *pfn); +extern void untrack_pfn_copy(struct vm_area_struct *dst_vma, + unsigned long pfn); extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn, unsigned long size, bool mm_wr_locked); extern void untrack_pfn_clear(struct vm_area_struct *vma); diff --git a/kernel/fork.c b/kernel/fork.c index f11ac96b7587..91171e58541c 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -504,6 +504,10 @@ struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) vma_numab_state_init(new); dup_anon_vma_name(orig, new); + /* track_pfn_copy() will later take care of copying internal state. */ + if (unlikely(new->vm_flags & VM_PFNMAP)) + untrack_pfn_clear(new); + return new; } diff --git a/mm/memory.c b/mm/memory.c index 4f6d9766a046..53f7b0aaf2a3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1362,12 +1362,12 @@ int copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) { pgd_t *src_pgd, *dst_pgd; - unsigned long next; unsigned long addr = src_vma->vm_start; unsigned long end = src_vma->vm_end; struct mm_struct *dst_mm = dst_vma->vm_mm; struct mm_struct *src_mm = src_vma->vm_mm; struct mmu_notifier_range range; + unsigned long next, pfn; bool is_cow; int ret; @@ -1378,11 +1378,7 @@ copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) return copy_hugetlb_page_range(dst_mm, src_mm, dst_vma, src_vma); if (unlikely(src_vma->vm_flags & VM_PFNMAP)) { - /* - * We do not free on error cases below as remove_vma - * gets called on error from higher level routine - */ - ret = track_pfn_copy(src_vma); + ret = track_pfn_copy(dst_vma, src_vma, &pfn); if (ret) return ret; } @@ -1419,7 +1415,6 @@ copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) continue; if (unlikely(copy_p4d_range(dst_vma, src_vma, dst_pgd, src_pgd, addr, next))) { - untrack_pfn_clear(dst_vma); ret = -ENOMEM; break; } @@ -1429,6 +1424,8 @@ copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) raw_write_seqcount_end(&src_mm->write_protect_seq); mmu_notifier_invalidate_range_end(&range); } + if (ret && unlikely(src_vma->vm_flags & VM_PFNMAP)) + untrack_pfn_copy(dst_vma, pfn); return ret; } |