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*参照元 [#lc5dc598] #backlinks *説明 [#c41493ca] -パス: [[linux-2.6.33/mm/memory.c]] -FIXME: これは何？ --説明 **引数 [#a2276094] -struct task_struct *tsk -- --[[linux-2.6.33/task_struct]] -struct mm_struct *mm -- --[[linux-2.6.33/mm_struct]] -unsigned long start -- -int nr_pages -- -int write -unsigned int foll_flags -- -int force -- -struct page **pages -- --[[linux-2.6.33/page]] -struct vm_area_struct **vmas - --[[linux-2.6.33/vm_area_struct]] **返り値 [#q6541b95] -int -- **参考 [#n5408a21] *実装 [#h309d47e] int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, int nr_pages, unsigned int gup_flags, struct page **pages, struct vm_area_struct **vmas) { int i; unsigned long vm_flags; if (nr_pages <= 0) return 0; VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET)); - --[[linux-2.6.33/VM_BUG_ON()]] - --[[linux-2.6.33/FOLL_GET]] /* * Require read or write permissions. * If FOLL_FORCE is set, we only require the "MAY" flags. */ vm_flags = (gup_flags & FOLL_WRITE) ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); vm_flags &= (gup_flags & FOLL_FORCE) ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); i = 0; - --[[linux-2.6.33/FOLL_WRITE]] - --[[linux-2.6.33/FOLL_FORCE]] - --[[linux-2.6.33/VM_WRITE]] - --[[linux-2.6.33/VM_MAYWRITE]] - --[[linux-2.6.33/VM_READ]] - --[[linux-2.6.33/VM_MAYREAD]] do { struct vm_area_struct *vma; vma = find_extend_vma(mm, start); - --[[linux-2.6.33/vm_area_struct]] - --[[linux-2.6.33/find_extended_vma()]] if (!vma && in_gate_area(tsk, start)) { unsigned long pg = start & PAGE_MASK; struct vm_area_struct *gate_vma = get_gate_vma(tsk); pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t *pte; - --[[linux-2.6.33/in_gate_area()]] - --[[linux-2.6.33/PAGE_MASK]] - --[[linux-2.6.33/get_gate_vma()]] - --[[linux-2.6.33/pgd_t]] - --[[linux-2.6.33/pud_t]] - --[[linux-2.6.33/pmd_t]] - --[[linux-2.6.33/pte_t]] /* user gate pages are read-only */ if (gup_flags & FOLL_WRITE) return i ? : -EFAULT; if (pg > TASK_SIZE) pgd = pgd_offset_k(pg); else pgd = pgd_offset_gate(mm, pg); - --[[linux-2.6.33/TASK_SIZE]] - --[[linux-2.6.33/pgd_offset_k()]] - --[[linux-2.6.33/pgd_offset_gate()]] BUG_ON(pgd_none(*pgd)); pud = pud_offset(pgd, pg); BUG_ON(pud_none(*pud)); pmd = pmd_offset(pud, pg); if (pmd_none(*pmd)) return i ? : -EFAULT; - --[[linux-2.6.33/BUG_ON()]] - --[[linux-2.6.33/pgd_none()]] - --[[linux-2.6.33/pud_offset()]] - --[[linux-2.6.33/pud_none()]] - --[[linux-2.6.33/pmd_offset()]] - --[[linux-2.6.33/pmd_none()]] pte = pte_offset_map(pmd, pg); if (pte_none(*pte)) { pte_unmap(pte); return i ? : -EFAULT; } - --[[linux-2.6.33/pte_offset_map()]] - --[[linux-2.6.33/pte_none()]] - --[[linux-2.6.33/pte_unmap()]] if (pages) { struct page *page = vm_normal_page(gate_vma, start, *pte); pages[i] = page; if (page) get_page(page); } pte_unmap(pte); - --[[linux-2.6.33/vm_normal_page()]] - --[[linux-2.6.33/get_page()]] if (vmas) vmas[i] = gate_vma; i++; start += PAGE_SIZE; nr_pages--; continue; } if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP)) || !(vm_flags & vma->vm_flags)) return i ? : -EFAULT; - --[[linux-2.6.33/VM_IO]] - --[[linux-2.6.33/VM_PFNMAP]] if (is_vm_hugetlb_page(vma)) { i = follow_hugetlb_page(mm, vma, pages, vmas, &start, &nr_pages, i, gup_flags); continue; } - --[[linux-2.6.33/is_vm_hugetlb_page()]] - --[[linux-2.6.33/follow_hugetlb_page()]] do { struct page *page; unsigned int foll_flags = gup_flags; /* * If we have a pending SIGKILL, don't keep faulting * pages and potentially allocating memory. */ if (unlikely(fatal_signal_pending(current))) return i ? i : -ERESTARTSYS; - --[[linux-2.6.33/unlikely()]] - --[[linux-2.6.33/current(global)]] - --[[linux-2.6.33/fatal_signal_pending()]] cond_resched(); - --[[linux-2.6.33/cond_resched()]] while (!(page = follow_page(vma, start, foll_flags))) { int ret; - --[[linux-2.6.33/follow_page()]] ret = handle_mm_fault(mm, vma, start, (foll_flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0); - --[[linux-2.6.33/handle_mm_fault()]] - --[[linux-2.6.33/FAULT_FLAG_WRITE]] if (ret & VM_FAULT_ERROR) { if (ret & VM_FAULT_OOM) return i ? i : -ENOMEM; if (ret & (VM_FAULT_HWPOISON|VM_FAULT_SIGBUS)) return i ? i : -EFAULT; BUG(); } - --[[linux-2.6.33/VM_FAULT_ERROR]] - --[[linux-2.6.33/VM_FAULT_OOM]] - --[[linux-2.6.33/VM_FAULT_HWPOISON]] - --[[linux-2.6.33/VM_FAULT_SIGBUS]] if (ret & VM_FAULT_MAJOR) tsk->maj_flt++; else tsk->min_flt++; - --[[linux-2.6.33/VM_FAULT_MAJOR]] /* * The VM_FAULT_WRITE bit tells us that * do_wp_page has broken COW when necessary, * even if maybe_mkwrite decided not to set * pte_write. We can thus safely do subsequent * page lookups as if they were reads. But only * do so when looping for pte_write is futile: * in some cases userspace may also be wanting * to write to the gotten user page, which a * read fault here might prevent (a readonly * page might get reCOWed by userspace write). */ if ((ret & VM_FAULT_WRITE) && !(vma->vm_flags & VM_WRITE)) foll_flags &= ~FOLL_WRITE; cond_resched(); - --[[linux-2.6.33/VM_FAULT_WRITE]] - --[[linux-2.6.33/VM_WRITE]] } if (IS_ERR(page)) return i ? i : PTR_ERR(page); - --[[linux-2.6.33/IS_ERR()]] - --[[linux-2.6.33/PTR_ERR()]] if (pages) { pages[i] = page; flush_anon_page(vma, page, start); flush_dcache_page(page); } - --[[linux-2.6.33/flush_anon_page()]] - --[[linux-2.6.33/flush_dcache_page()]] if (vmas) vmas[i] = vma; i++; start += PAGE_SIZE; nr_pages--; } while (nr_pages && start < vma->vm_end); } while (nr_pages); return i; } *コメント [#u245a6d7]
