diff options
Diffstat (limited to 'mm/gup.c')
| -rw-r--r-- | mm/gup.c | 101 |
1 files changed, 72 insertions, 29 deletions
@@ -10,7 +10,7 @@ #include <linux/swap.h> #include <linux/swapops.h> -#include <linux/sched.h> +#include <linux/sched/signal.h> #include <linux/rwsem.h> #include <linux/hugetlb.h> @@ -226,6 +226,7 @@ struct page *follow_page_mask(struct vm_area_struct *vma, unsigned int *page_mask) { pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pmd_t *pmd; spinlock_t *ptl; @@ -243,8 +244,13 @@ struct page *follow_page_mask(struct vm_area_struct *vma, pgd = pgd_offset(mm, address); if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) return no_page_table(vma, flags); - - pud = pud_offset(pgd, address); + p4d = p4d_offset(pgd, address); + if (p4d_none(*p4d)) + return no_page_table(vma, flags); + BUILD_BUG_ON(p4d_huge(*p4d)); + if (unlikely(p4d_bad(*p4d))) + return no_page_table(vma, flags); + pud = pud_offset(p4d, address); if (pud_none(*pud)) return no_page_table(vma, flags); if (pud_huge(*pud) && vma->vm_flags & VM_HUGETLB) { @@ -253,6 +259,13 @@ struct page *follow_page_mask(struct vm_area_struct *vma, return page; return no_page_table(vma, flags); } + if (pud_devmap(*pud)) { + ptl = pud_lock(mm, pud); + page = follow_devmap_pud(vma, address, pud, flags); + spin_unlock(ptl); + if (page) + return page; + } if (unlikely(pud_bad(*pud))) return no_page_table(vma, flags); @@ -265,8 +278,6 @@ struct page *follow_page_mask(struct vm_area_struct *vma, return page; return no_page_table(vma, flags); } - if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) - return no_page_table(vma, flags); if (pmd_devmap(*pmd)) { ptl = pmd_lock(mm, pmd); page = follow_devmap_pmd(vma, address, pmd, flags); @@ -277,6 +288,9 @@ struct page *follow_page_mask(struct vm_area_struct *vma, if (likely(!pmd_trans_huge(*pmd))) return follow_page_pte(vma, address, pmd, flags); + if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) + return no_page_table(vma, flags); + ptl = pmd_lock(mm, pmd); if (unlikely(!pmd_trans_huge(*pmd))) { spin_unlock(ptl); @@ -317,6 +331,7 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address, struct page **page) { pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pmd_t *pmd; pte_t *pte; @@ -330,7 +345,9 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address, else pgd = pgd_offset_gate(mm, address); BUG_ON(pgd_none(*pgd)); - pud = pud_offset(pgd, address); + p4d = p4d_offset(pgd, address); + BUG_ON(p4d_none(*p4d)); + pud = pud_offset(p4d, address); BUG_ON(pud_none(*pud)); pmd = pmd_offset(pud, address); if (pmd_none(*pmd)) @@ -572,7 +589,7 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, if (is_vm_hugetlb_page(vma)) { i = follow_hugetlb_page(mm, vma, pages, vmas, &start, &nr_pages, i, - gup_flags); + gup_flags, nonblocking); continue; } } @@ -632,7 +649,8 @@ next_page: return i; } -bool vma_permits_fault(struct vm_area_struct *vma, unsigned int fault_flags) +static bool vma_permits_fault(struct vm_area_struct *vma, + unsigned int fault_flags) { bool write = !!(fault_flags & FAULT_FLAG_WRITE); bool foreign = !!(fault_flags & FAULT_FLAG_REMOTE); @@ -857,18 +875,17 @@ long get_user_pages_locked(unsigned long start, unsigned long nr_pages, EXPORT_SYMBOL(get_user_pages_locked); /* - * Same as get_user_pages_unlocked(...., FOLL_TOUCH) but it allows to - * pass additional gup_flags as last parameter (like FOLL_HWPOISON). + * Same as get_user_pages_unlocked(...., FOLL_TOUCH) but it allows for + * tsk, mm to be specified. * * NOTE: here FOLL_TOUCH is not set implicitly and must be set by the - * caller if required (just like with __get_user_pages). "FOLL_GET", - * "FOLL_WRITE" and "FOLL_FORCE" are set implicitly as needed - * according to the parameters "pages", "write", "force" - * respectively. + * caller if required (just like with __get_user_pages). "FOLL_GET" + * is set implicitly if "pages" is non-NULL. */ -__always_inline long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm, - unsigned long start, unsigned long nr_pages, - struct page **pages, unsigned int gup_flags) +static __always_inline long __get_user_pages_unlocked(struct task_struct *tsk, + struct mm_struct *mm, unsigned long start, + unsigned long nr_pages, struct page **pages, + unsigned int gup_flags) { long ret; int locked = 1; @@ -880,7 +897,6 @@ __always_inline long __get_user_pages_unlocked(struct task_struct *tsk, struct m up_read(&mm->mmap_sem); return ret; } -EXPORT_SYMBOL(__get_user_pages_unlocked); /* * get_user_pages_unlocked() is suitable to replace the form: @@ -894,10 +910,8 @@ EXPORT_SYMBOL(__get_user_pages_unlocked); * get_user_pages_unlocked(tsk, mm, ..., pages); * * It is functionally equivalent to get_user_pages_fast so - * get_user_pages_fast should be used instead, if the two parameters - * "tsk" and "mm" are respectively equal to current and current->mm, - * or if "force" shall be set to 1 (get_user_pages_fast misses the - * "force" parameter). + * get_user_pages_fast should be used instead if specific gup_flags + * (e.g. FOLL_FORCE) are not required. */ long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, struct page **pages, unsigned int gup_flags) @@ -920,6 +934,9 @@ EXPORT_SYMBOL(get_user_pages_unlocked); * only intends to ensure the pages are faulted in. * @vmas: array of pointers to vmas corresponding to each page. * Or NULL if the caller does not require them. + * @locked: pointer to lock flag indicating whether lock is held and + * subsequently whether VM_FAULT_RETRY functionality can be + * utilised. Lock must initially be held. * * Returns number of pages pinned. This may be fewer than the number * requested. If nr_pages is 0 or negative, returns 0. If no pages @@ -963,10 +980,10 @@ EXPORT_SYMBOL(get_user_pages_unlocked); long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, - struct vm_area_struct **vmas) + struct vm_area_struct **vmas, int *locked) { return __get_user_pages_locked(tsk, mm, start, nr_pages, pages, vmas, - NULL, false, + locked, true, gup_flags | FOLL_TOUCH | FOLL_REMOTE); } EXPORT_SYMBOL(get_user_pages_remote); @@ -974,8 +991,9 @@ EXPORT_SYMBOL(get_user_pages_remote); /* * This is the same as get_user_pages_remote(), just with a * less-flexible calling convention where we assume that the task - * and mm being operated on are the current task's. We also - * obviously don't pass FOLL_REMOTE in here. + * and mm being operated on are the current task's and don't allow + * passing of a locked parameter. We also obviously don't pass + * FOLL_REMOTE in here. */ long get_user_pages(unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, @@ -1391,13 +1409,13 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end, return 1; } -static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end, +static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end, int write, struct page **pages, int *nr) { unsigned long next; pud_t *pudp; - pudp = pud_offset(&pgd, addr); + pudp = pud_offset(&p4d, addr); do { pud_t pud = READ_ONCE(*pudp); @@ -1419,6 +1437,31 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end, return 1; } +static int gup_p4d_range(pgd_t pgd, unsigned long addr, unsigned long end, + int write, struct page **pages, int *nr) +{ + unsigned long next; + p4d_t *p4dp; + + p4dp = p4d_offset(&pgd, addr); + do { + p4d_t p4d = READ_ONCE(*p4dp); + + next = p4d_addr_end(addr, end); + if (p4d_none(p4d)) + return 0; + BUILD_BUG_ON(p4d_huge(p4d)); + if (unlikely(is_hugepd(__hugepd(p4d_val(p4d))))) { + if (!gup_huge_pd(__hugepd(p4d_val(p4d)), addr, + P4D_SHIFT, next, write, pages, nr)) + return 0; + } else if (!gup_pud_range(p4d, addr, next, write, pages, nr)) + return 0; + } while (p4dp++, addr = next, addr != end); + + return 1; +} + /* * Like get_user_pages_fast() except it's IRQ-safe in that it won't fall back to * the regular GUP. It will only return non-negative values. @@ -1469,7 +1512,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, if (!gup_huge_pd(__hugepd(pgd_val(pgd)), addr, PGDIR_SHIFT, next, write, pages, &nr)) break; - } else if (!gup_pud_range(pgd, addr, next, write, pages, &nr)) + } else if (!gup_p4d_range(pgd, addr, next, write, pages, &nr)) break; } while (pgdp++, addr = next, addr != end); local_irq_restore(flags); |
