Rather than open-code the intricacies of walking the 4-level page tables, use the generic page table walker apply_to_page_range() instead.
The important change is that it now cleans up after an unsuccessful insertion and propagates the correct error. The current failure may lead to a WARN if we encounter ENOMEM in one vmap_pte_range() and later retry with the same page range. WARNING: CPU: 0 PID: 605 at mm/vmalloc.c:136 vmap_page_range_noflush+0x2c1/0x340 i.e. WARN_ON(!pte_none(*pte)) v2: Don't convert the vunmap code over to apply_to_page_range() as it may try to allocate during atomic sections, such as exiting a task: [ 9.837563] [<ffffffff810519b0>] pte_alloc_one_kernel+0x10/0x20 [ 9.837568] [<ffffffff811a7486>] __pte_alloc_kernel+0x16/0xa0 [ 9.837572] [<ffffffff811aaa76>] apply_to_page_range+0x3f6/0x460 [ 9.837576] [<ffffffff811b8888>] free_unmap_vmap_area_noflush+0x28/0x40 [ 9.837579] [<ffffffff811b9dcd>] remove_vm_area+0x4d/0x60 [ 9.837582] [<ffffffff811b9e09>] __vunmap+0x29/0x130 [ 9.837585] [<ffffffff811b9f7d>] vfree+0x3d/0x90 [ 9.837589] [<ffffffff8107ace6>] put_task_stack+0x76/0x130 References: https://bugs.freedesktop.org/show_bug.cgi?id=98269 Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk> Cc: Andrew Morton <a...@linux-foundation.org> Cc: David Rientjes <rient...@google.com> Cc: Vladimir Davydov <vdavydov....@gmail.com> Cc: Johannes Weiner <han...@cmpxchg.org> Cc: Mel Gorman <mgor...@techsingularity.net> Cc: Wang Xiaoqiang <wangx...@lzu.edu.cn> Cc: Jerome Marchand <jmarc...@redhat.com> Cc: Joonsoo Kim <iamjoonsoo....@lge.com> Cc: linux...@kvack.org --- mm/vmalloc.c | 93 ++++++++++++++++++------------------------------------------ 1 file changed, 27 insertions(+), 66 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index f2481cb4e6b2..7e945c63c7ef 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -117,63 +117,27 @@ static void vunmap_page_range(unsigned long addr, unsigned long end) } while (pgd++, addr = next, addr != end); } -static int vmap_pte_range(pmd_t *pmd, unsigned long addr, - unsigned long end, pgprot_t prot, struct page **pages, int *nr) -{ - pte_t *pte; - - /* - * nr is a running index into the array which helps higher level - * callers keep track of where we're up to. - */ - - pte = pte_alloc_kernel(pmd, addr); - if (!pte) - return -ENOMEM; - do { - struct page *page = pages[*nr]; - - if (WARN_ON(!pte_none(*pte))) - return -EBUSY; - if (WARN_ON(!page)) - return -ENOMEM; - set_pte_at(&init_mm, addr, pte, mk_pte(page, prot)); - (*nr)++; - } while (pte++, addr += PAGE_SIZE, addr != end); - return 0; -} +struct vmap_page { + pgprot_t prot; + struct page **pages; + unsigned long count; +}; -static int vmap_pmd_range(pud_t *pud, unsigned long addr, - unsigned long end, pgprot_t prot, struct page **pages, int *nr) +static int vmap_page(pte_t *pte, pgtable_t token, + unsigned long addr, void *data) { - pmd_t *pmd; - unsigned long next; - - pmd = pmd_alloc(&init_mm, pud, addr); - if (!pmd) - return -ENOMEM; - do { - next = pmd_addr_end(addr, end); - if (vmap_pte_range(pmd, addr, next, prot, pages, nr)) - return -ENOMEM; - } while (pmd++, addr = next, addr != end); - return 0; -} + struct vmap_page *v = data; + struct page *page; -static int vmap_pud_range(pgd_t *pgd, unsigned long addr, - unsigned long end, pgprot_t prot, struct page **pages, int *nr) -{ - pud_t *pud; - unsigned long next; + if (WARN_ON(!pte_none(*pte))) + return -EBUSY; - pud = pud_alloc(&init_mm, pgd, addr); - if (!pud) + page = v->pages[v->count]; + if (WARN_ON(!page)) return -ENOMEM; - do { - next = pud_addr_end(addr, end); - if (vmap_pmd_range(pud, addr, next, prot, pages, nr)) - return -ENOMEM; - } while (pud++, addr = next, addr != end); + + set_pte_at(&init_mm, addr, pte, mk_pte(page, v->prot)); + v->count++; return 0; } @@ -186,22 +150,19 @@ static int vmap_pud_range(pgd_t *pgd, unsigned long addr, static int vmap_page_range_noflush(unsigned long start, unsigned long end, pgprot_t prot, struct page **pages) { - pgd_t *pgd; - unsigned long next; - unsigned long addr = start; - int err = 0; - int nr = 0; + struct vmap_page v = { prot, pages }; + int err; - BUG_ON(addr >= end); - pgd = pgd_offset_k(addr); - do { - next = pgd_addr_end(addr, end); - err = vmap_pud_range(pgd, addr, next, prot, pages, &nr); - if (err) - return err; - } while (pgd++, addr = next, addr != end); + if ((end - start) >> PAGE_SHIFT > INT_MAX) + return -EINVAL; + + err = apply_to_page_range(&init_mm, start, end - start, vmap_page, &v); + if (unlikely(err)) { + vunmap_page_range(start, start + (v.count << PAGE_SHIFT)); + return err; + } - return nr; + return v.count; } static int vmap_page_range(unsigned long start, unsigned long end, -- 2.9.3 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
