| Message ID | 20230306225024.264858-5-axelrasmussen@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: userfaultfd: refactor and add UFFDIO_CONTINUE_MODE_WP | expand |
On Mon, Mar 06, 2023 at 02:50:23PM -0800, Axel Rasmussen wrote: > We have a lot of functions which take an address + length pair, > currently passed as separate arguments. However, in our userspace API we > already have struct uffdio_range, which is exactly this pair, and this > is what we get from userspace when ioctls are called. > > Instead of splitting the struct up into two separate arguments, just > plumb the struct through to the functions which use it (once we get to > the mfill_atomic_pte level, we're dealing with single (huge)pages, so we > don't need both parts). > > Relatedly, for waking, just re-use this existing structure instead of > defining a new "struct uffdio_wake_range". > > Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> > --- > fs/userfaultfd.c | 107 +++++++++++++--------------------- > include/linux/userfaultfd_k.h | 17 +++--- > mm/userfaultfd.c | 92 ++++++++++++++--------------- > 3 files changed, 96 insertions(+), 120 deletions(-) > > diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c > index b8e328123b71..984b63b0fc75 100644 > --- a/fs/userfaultfd.c > +++ b/fs/userfaultfd.c > @@ -95,11 +95,6 @@ struct userfaultfd_wait_queue { > bool waken; > }; > > -struct userfaultfd_wake_range { > - unsigned long start; > - unsigned long len; > -}; Would there still be a difference on e.g. 32 bits systems? [...] > static __always_inline int validate_range(struct mm_struct *mm, > - __u64 start, __u64 len) > + const struct uffdio_range *range) > { > __u64 task_size = mm->task_size; > > - if (start & ~PAGE_MASK) > + if (range->start & ~PAGE_MASK) > return -EINVAL; > - if (len & ~PAGE_MASK) > + if (range->len & ~PAGE_MASK) > return -EINVAL; > - if (!len) > + if (!range->len) > return -EINVAL; > - if (start < mmap_min_addr) > + if (range->start < mmap_min_addr) > return -EINVAL; > - if (start >= task_size) > + if (range->start >= task_size) > return -EINVAL; > - if (len > task_size - start) > + if (range->len > task_size - range->start) > return -EINVAL; > return 0; > } Personally I don't like a lot on such a change. :( It avoids one parameter being passed over but it can add a lot indirections. Do you strongly suggest this? Shall we move on without this so to not block the last patch (which I assume is the one you're looking for)? Thanks,
> On Mar 6, 2023, at 5:19 PM, Peter Xu <peterx@redhat.com> wrote: > > !! External Email > > On Mon, Mar 06, 2023 at 02:50:23PM -0800, Axel Rasmussen wrote: >> We have a lot of functions which take an address + length pair, >> currently passed as separate arguments. However, in our userspace API we >> already have struct uffdio_range, which is exactly this pair, and this >> is what we get from userspace when ioctls are called. >> >> Instead of splitting the struct up into two separate arguments, just >> plumb the struct through to the functions which use it (once we get to >> the mfill_atomic_pte level, we're dealing with single (huge)pages, so we >> don't need both parts). >> >> Relatedly, for waking, just re-use this existing structure instead of >> defining a new "struct uffdio_wake_range". >> >> Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> >> --- >> fs/userfaultfd.c | 107 +++++++++++++--------------------- >> include/linux/userfaultfd_k.h | 17 +++--- >> mm/userfaultfd.c | 92 ++++++++++++++--------------- >> 3 files changed, 96 insertions(+), 120 deletions(-) >> >> diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c >> index b8e328123b71..984b63b0fc75 100644 >> --- a/fs/userfaultfd.c >> +++ b/fs/userfaultfd.c >> @@ -95,11 +95,6 @@ struct userfaultfd_wait_queue { >> bool waken; >> }; >> >> -struct userfaultfd_wake_range { >> - unsigned long start; >> - unsigned long len; >> -}; > > Would there still be a difference on e.g. 32 bits systems? > > [...] > >> static __always_inline int validate_range(struct mm_struct *mm, >> - __u64 start, __u64 len) >> + const struct uffdio_range *range) >> { >> __u64 task_size = mm->task_size; >> >> - if (start & ~PAGE_MASK) >> + if (range->start & ~PAGE_MASK) >> return -EINVAL; >> - if (len & ~PAGE_MASK) >> + if (range->len & ~PAGE_MASK) >> return -EINVAL; >> - if (!len) >> + if (!range->len) >> return -EINVAL; >> - if (start < mmap_min_addr) >> + if (range->start < mmap_min_addr) >> return -EINVAL; >> - if (start >= task_size) >> + if (range->start >= task_size) >> return -EINVAL; >> - if (len > task_size - start) >> + if (range->len > task_size - range->start) >> return -EINVAL; >> return 0; >> } > > Personally I don't like a lot on such a change. :( It avoids one parameter > being passed over but it can add a lot indirections. > > Do you strongly suggest this? Shall we move on without this so to not > block the last patch (which I assume is the one you're looking for)? Just in case you missed, it is __always_inline, so I presume that from a generated code point-of-view it is the same. Having said that, small assignments to local start, let and range variables would make the code easier to read and reduce the change-set.
Hi Axel,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on linus/master]
[also build test ERROR on v6.3-rc1]
[cannot apply to akpm-mm/mm-everything next-20230308]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Axel-Rasmussen/mm-userfaultfd-rename-functions-for-clarity-consistency/20230307-065203
patch link: https://lore.kernel.org/r/20230306225024.264858-5-axelrasmussen%40google.com
patch subject: [PATCH v3 4/5] mm: userfaultfd: don't separate addr + len arguments
config: x86_64-randconfig-a011-20230306 (https://download.01.org/0day-ci/archive/20230308/202303081703.nwxAgIVH-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/cee642b93be3ae01c7cc737c0176cbc16074a25a
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Axel-Rasmussen/mm-userfaultfd-rename-functions-for-clarity-consistency/20230307-065203
git checkout cee642b93be3ae01c7cc737c0176cbc16074a25a
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202303081703.nwxAgIVH-lkp@intel.com/
All errors (new ones prefixed by >>):
>> mm/userfaultfd.c:577:52: error: passing 'const struct uffdio_range *' to parameter of incompatible type 'struct uffdio_range'
return mfill_atomic_hugetlb(dst_vma, src_start, dst, flags);
^~~
mm/userfaultfd.c:463:29: note: passing argument to parameter 'dst' here
struct uffdio_range dst,
^
1 error generated.
vim +577 mm/userfaultfd.c
508
509 static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm,
510 unsigned long src_start,
511 const struct uffdio_range *dst,
512 atomic_t *mmap_changing,
513 uffd_flags_t flags)
514 {
515 struct vm_area_struct *dst_vma;
516 ssize_t err;
517 pmd_t *dst_pmd;
518 unsigned long src_addr, dst_addr;
519 long copied;
520 struct page *page;
521
522 /*
523 * Sanitize the command parameters:
524 */
525 BUG_ON(dst->start & ~PAGE_MASK);
526 BUG_ON(dst->len & ~PAGE_MASK);
527
528 /* Does the address range wrap, or is the span zero-sized? */
529 BUG_ON(src_start + dst->len <= src_start);
530 BUG_ON(dst->start + dst->len <= dst->start);
531
532 src_addr = src_start;
533 dst_addr = dst->start;
534 copied = 0;
535 page = NULL;
536 retry:
537 mmap_read_lock(dst_mm);
538
539 /*
540 * If memory mappings are changing because of non-cooperative
541 * operation (e.g. mremap) running in parallel, bail out and
542 * request the user to retry later
543 */
544 err = -EAGAIN;
545 if (mmap_changing && atomic_read(mmap_changing))
546 goto out_unlock;
547
548 /*
549 * Make sure the vma is not shared, that the dst range is
550 * both valid and fully within a single existing vma.
551 */
552 err = -ENOENT;
553 dst_vma = find_dst_vma(dst_mm, dst);
554 if (!dst_vma)
555 goto out_unlock;
556
557 err = -EINVAL;
558 /*
559 * shmem_zero_setup is invoked in mmap for MAP_ANONYMOUS|MAP_SHARED but
560 * it will overwrite vm_ops, so vma_is_anonymous must return false.
561 */
562 if (WARN_ON_ONCE(vma_is_anonymous(dst_vma) &&
563 dst_vma->vm_flags & VM_SHARED))
564 goto out_unlock;
565
566 /*
567 * validate 'mode' now that we know the dst_vma: don't allow
568 * a wrprotect copy if the userfaultfd didn't register as WP.
569 */
570 if ((flags & MFILL_ATOMIC_WP) && !(dst_vma->vm_flags & VM_UFFD_WP))
571 goto out_unlock;
572
573 /*
574 * If this is a HUGETLB vma, pass off to appropriate routine
575 */
576 if (is_vm_hugetlb_page(dst_vma))
> 577 return mfill_atomic_hugetlb(dst_vma, src_start, dst, flags);
578
579 if (!vma_is_anonymous(dst_vma) && !vma_is_shmem(dst_vma))
580 goto out_unlock;
581 if (!vma_is_shmem(dst_vma) &&
582 (flags & MFILL_ATOMIC_MODE_MASK) == MFILL_ATOMIC_CONTINUE)
583 goto out_unlock;
584
585 /*
586 * Ensure the dst_vma has a anon_vma or this page
587 * would get a NULL anon_vma when moved in the
588 * dst_vma.
589 */
590 err = -ENOMEM;
591 if (!(dst_vma->vm_flags & VM_SHARED) &&
592 unlikely(anon_vma_prepare(dst_vma)))
593 goto out_unlock;
594
595 while (src_addr < src_start + dst->len) {
596 pmd_t dst_pmdval;
597
598 BUG_ON(dst_addr >= dst->start + dst->len);
599
600 dst_pmd = mm_alloc_pmd(dst_mm, dst_addr);
601 if (unlikely(!dst_pmd)) {
602 err = -ENOMEM;
603 break;
604 }
605
606 dst_pmdval = pmdp_get_lockless(dst_pmd);
607 /*
608 * If the dst_pmd is mapped as THP don't
609 * override it and just be strict.
610 */
611 if (unlikely(pmd_trans_huge(dst_pmdval))) {
612 err = -EEXIST;
613 break;
614 }
615 if (unlikely(pmd_none(dst_pmdval)) &&
616 unlikely(__pte_alloc(dst_mm, dst_pmd))) {
617 err = -ENOMEM;
618 break;
619 }
620 /* If an huge pmd materialized from under us fail */
621 if (unlikely(pmd_trans_huge(*dst_pmd))) {
622 err = -EFAULT;
623 break;
624 }
625
626 BUG_ON(pmd_none(*dst_pmd));
627 BUG_ON(pmd_trans_huge(*dst_pmd));
628
629 err = mfill_atomic_pte(dst_pmd, dst_vma, dst_addr,
630 src_addr, &page, flags);
631 cond_resched();
632
633 if (unlikely(err == -ENOENT)) {
634 void *page_kaddr;
635
636 mmap_read_unlock(dst_mm);
637 BUG_ON(!page);
638
639 page_kaddr = kmap_local_page(page);
640 err = copy_from_user(page_kaddr,
641 (const void __user *) src_addr,
642 PAGE_SIZE);
643 kunmap_local(page_kaddr);
644 if (unlikely(err)) {
645 err = -EFAULT;
646 goto out;
647 }
648 flush_dcache_page(page);
649 goto retry;
650 } else
651 BUG_ON(page);
652
653 if (!err) {
654 dst_addr += PAGE_SIZE;
655 src_addr += PAGE_SIZE;
656 copied += PAGE_SIZE;
657
658 if (fatal_signal_pending(current))
659 err = -EINTR;
660 }
661 if (err)
662 break;
663 }
664
665 out_unlock:
666 mmap_read_unlock(dst_mm);
667 out:
668 if (page)
669 put_page(page);
670 BUG_ON(copied < 0);
671 BUG_ON(err > 0);
672 BUG_ON(!copied && !err);
673 return copied ? copied : err;
674 }
675
On Wed, Mar 8, 2023 at 1:52 AM kernel test robot <lkp@intel.com> wrote: > > Hi Axel, > > Thank you for the patch! Yet something to improve: > > [auto build test ERROR on linus/master] > [also build test ERROR on v6.3-rc1] > [cannot apply to akpm-mm/mm-everything next-20230308] > [If your patch is applied to the wrong git tree, kindly drop us a note. > And when submitting patch, we suggest to use '--base' as documented in > https://git-scm.com/docs/git-format-patch#_base_tree_information] > > url: https://github.com/intel-lab-lkp/linux/commits/Axel-Rasmussen/mm-userfaultfd-rename-functions-for-clarity-consistency/20230307-065203 > patch link: https://lore.kernel.org/r/20230306225024.264858-5-axelrasmussen%40google.com > patch subject: [PATCH v3 4/5] mm: userfaultfd: don't separate addr + len arguments > config: x86_64-randconfig-a011-20230306 (https://download.01.org/0day-ci/archive/20230308/202303081703.nwxAgIVH-lkp@intel.com/config) > compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1) > reproduce (this is a W=1 build): > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > chmod +x ~/bin/make.cross > # https://github.com/intel-lab-lkp/linux/commit/cee642b93be3ae01c7cc737c0176cbc16074a25a > git remote add linux-review https://github.com/intel-lab-lkp/linux > git fetch --no-tags linux-review Axel-Rasmussen/mm-userfaultfd-rename-functions-for-clarity-consistency/20230307-065203 > git checkout cee642b93be3ae01c7cc737c0176cbc16074a25a > # save the config file > mkdir build_dir && cp config build_dir/.config > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash > > If you fix the issue, kindly add following tag where applicable > | Reported-by: kernel test robot <lkp@intel.com> > | Link: https://lore.kernel.org/oe-kbuild-all/202303081703.nwxAgIVH-lkp@intel.com/ > > All errors (new ones prefixed by >>): > > >> mm/userfaultfd.c:577:52: error: passing 'const struct uffdio_range *' to parameter of incompatible type 'struct uffdio_range' > return mfill_atomic_hugetlb(dst_vma, src_start, dst, flags); > ^~~ > mm/userfaultfd.c:463:29: note: passing argument to parameter 'dst' here > struct uffdio_range dst, > ^ > 1 error generated. Whoops. :) I admittedly didn't test with !CONFIG_HUGETLB_PAGE. The next version of this series will drop this patch as per discussion though, so the issue is moot. > > > vim +577 mm/userfaultfd.c > > 508 > 509 static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm, > 510 unsigned long src_start, > 511 const struct uffdio_range *dst, > 512 atomic_t *mmap_changing, > 513 uffd_flags_t flags) > 514 { > 515 struct vm_area_struct *dst_vma; > 516 ssize_t err; > 517 pmd_t *dst_pmd; > 518 unsigned long src_addr, dst_addr; > 519 long copied; > 520 struct page *page; > 521 > 522 /* > 523 * Sanitize the command parameters: > 524 */ > 525 BUG_ON(dst->start & ~PAGE_MASK); > 526 BUG_ON(dst->len & ~PAGE_MASK); > 527 > 528 /* Does the address range wrap, or is the span zero-sized? */ > 529 BUG_ON(src_start + dst->len <= src_start); > 530 BUG_ON(dst->start + dst->len <= dst->start); > 531 > 532 src_addr = src_start; > 533 dst_addr = dst->start; > 534 copied = 0; > 535 page = NULL; > 536 retry: > 537 mmap_read_lock(dst_mm); > 538 > 539 /* > 540 * If memory mappings are changing because of non-cooperative > 541 * operation (e.g. mremap) running in parallel, bail out and > 542 * request the user to retry later > 543 */ > 544 err = -EAGAIN; > 545 if (mmap_changing && atomic_read(mmap_changing)) > 546 goto out_unlock; > 547 > 548 /* > 549 * Make sure the vma is not shared, that the dst range is > 550 * both valid and fully within a single existing vma. > 551 */ > 552 err = -ENOENT; > 553 dst_vma = find_dst_vma(dst_mm, dst); > 554 if (!dst_vma) > 555 goto out_unlock; > 556 > 557 err = -EINVAL; > 558 /* > 559 * shmem_zero_setup is invoked in mmap for MAP_ANONYMOUS|MAP_SHARED but > 560 * it will overwrite vm_ops, so vma_is_anonymous must return false. > 561 */ > 562 if (WARN_ON_ONCE(vma_is_anonymous(dst_vma) && > 563 dst_vma->vm_flags & VM_SHARED)) > 564 goto out_unlock; > 565 > 566 /* > 567 * validate 'mode' now that we know the dst_vma: don't allow > 568 * a wrprotect copy if the userfaultfd didn't register as WP. > 569 */ > 570 if ((flags & MFILL_ATOMIC_WP) && !(dst_vma->vm_flags & VM_UFFD_WP)) > 571 goto out_unlock; > 572 > 573 /* > 574 * If this is a HUGETLB vma, pass off to appropriate routine > 575 */ > 576 if (is_vm_hugetlb_page(dst_vma)) > > 577 return mfill_atomic_hugetlb(dst_vma, src_start, dst, flags); > 578 > 579 if (!vma_is_anonymous(dst_vma) && !vma_is_shmem(dst_vma)) > 580 goto out_unlock; > 581 if (!vma_is_shmem(dst_vma) && > 582 (flags & MFILL_ATOMIC_MODE_MASK) == MFILL_ATOMIC_CONTINUE) > 583 goto out_unlock; > 584 > 585 /* > 586 * Ensure the dst_vma has a anon_vma or this page > 587 * would get a NULL anon_vma when moved in the > 588 * dst_vma. > 589 */ > 590 err = -ENOMEM; > 591 if (!(dst_vma->vm_flags & VM_SHARED) && > 592 unlikely(anon_vma_prepare(dst_vma))) > 593 goto out_unlock; > 594 > 595 while (src_addr < src_start + dst->len) { > 596 pmd_t dst_pmdval; > 597 > 598 BUG_ON(dst_addr >= dst->start + dst->len); > 599 > 600 dst_pmd = mm_alloc_pmd(dst_mm, dst_addr); > 601 if (unlikely(!dst_pmd)) { > 602 err = -ENOMEM; > 603 break; > 604 } > 605 > 606 dst_pmdval = pmdp_get_lockless(dst_pmd); > 607 /* > 608 * If the dst_pmd is mapped as THP don't > 609 * override it and just be strict. > 610 */ > 611 if (unlikely(pmd_trans_huge(dst_pmdval))) { > 612 err = -EEXIST; > 613 break; > 614 } > 615 if (unlikely(pmd_none(dst_pmdval)) && > 616 unlikely(__pte_alloc(dst_mm, dst_pmd))) { > 617 err = -ENOMEM; > 618 break; > 619 } > 620 /* If an huge pmd materialized from under us fail */ > 621 if (unlikely(pmd_trans_huge(*dst_pmd))) { > 622 err = -EFAULT; > 623 break; > 624 } > 625 > 626 BUG_ON(pmd_none(*dst_pmd)); > 627 BUG_ON(pmd_trans_huge(*dst_pmd)); > 628 > 629 err = mfill_atomic_pte(dst_pmd, dst_vma, dst_addr, > 630 src_addr, &page, flags); > 631 cond_resched(); > 632 > 633 if (unlikely(err == -ENOENT)) { > 634 void *page_kaddr; > 635 > 636 mmap_read_unlock(dst_mm); > 637 BUG_ON(!page); > 638 > 639 page_kaddr = kmap_local_page(page); > 640 err = copy_from_user(page_kaddr, > 641 (const void __user *) src_addr, > 642 PAGE_SIZE); > 643 kunmap_local(page_kaddr); > 644 if (unlikely(err)) { > 645 err = -EFAULT; > 646 goto out; > 647 } > 648 flush_dcache_page(page); > 649 goto retry; > 650 } else > 651 BUG_ON(page); > 652 > 653 if (!err) { > 654 dst_addr += PAGE_SIZE; > 655 src_addr += PAGE_SIZE; > 656 copied += PAGE_SIZE; > 657 > 658 if (fatal_signal_pending(current)) > 659 err = -EINTR; > 660 } > 661 if (err) > 662 break; > 663 } > 664 > 665 out_unlock: > 666 mmap_read_unlock(dst_mm); > 667 out: > 668 if (page) > 669 put_page(page); > 670 BUG_ON(copied < 0); > 671 BUG_ON(err > 0); > 672 BUG_ON(!copied && !err); > 673 return copied ? copied : err; > 674 } > 675 > > -- > 0-DAY CI Kernel Test Service > https://github.com/intel/lkp-tests
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index b8e328123b71..984b63b0fc75 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -95,11 +95,6 @@ struct userfaultfd_wait_queue { bool waken; }; -struct userfaultfd_wake_range { - unsigned long start; - unsigned long len; -}; - /* internal indication that UFFD_API ioctl was successfully executed */ #define UFFD_FEATURE_INITIALIZED (1u << 31) @@ -126,7 +121,7 @@ static void userfaultfd_set_vm_flags(struct vm_area_struct *vma, static int userfaultfd_wake_function(wait_queue_entry_t *wq, unsigned mode, int wake_flags, void *key) { - struct userfaultfd_wake_range *range = key; + struct uffdio_range *range = key; int ret; struct userfaultfd_wait_queue *uwq; unsigned long start, len; @@ -881,7 +876,7 @@ static int userfaultfd_release(struct inode *inode, struct file *file) struct mm_struct *mm = ctx->mm; struct vm_area_struct *vma, *prev; /* len == 0 means wake all */ - struct userfaultfd_wake_range range = { .len = 0, }; + struct uffdio_range range = {0}; unsigned long new_flags; VMA_ITERATOR(vmi, mm, 0); @@ -1226,7 +1221,7 @@ static ssize_t userfaultfd_read(struct file *file, char __user *buf, } static void __wake_userfault(struct userfaultfd_ctx *ctx, - struct userfaultfd_wake_range *range) + struct uffdio_range *range) { spin_lock_irq(&ctx->fault_pending_wqh.lock); /* wake all in the range and autoremove */ @@ -1239,7 +1234,7 @@ static void __wake_userfault(struct userfaultfd_ctx *ctx, } static __always_inline void wake_userfault(struct userfaultfd_ctx *ctx, - struct userfaultfd_wake_range *range) + struct uffdio_range *range) { unsigned seq; bool need_wakeup; @@ -1270,21 +1265,21 @@ static __always_inline void wake_userfault(struct userfaultfd_ctx *ctx, } static __always_inline int validate_range(struct mm_struct *mm, - __u64 start, __u64 len) + const struct uffdio_range *range) { __u64 task_size = mm->task_size; - if (start & ~PAGE_MASK) + if (range->start & ~PAGE_MASK) return -EINVAL; - if (len & ~PAGE_MASK) + if (range->len & ~PAGE_MASK) return -EINVAL; - if (!len) + if (!range->len) return -EINVAL; - if (start < mmap_min_addr) + if (range->start < mmap_min_addr) return -EINVAL; - if (start >= task_size) + if (range->start >= task_size) return -EINVAL; - if (len > task_size - start) + if (range->len > task_size - range->start) return -EINVAL; return 0; } @@ -1331,8 +1326,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, vm_flags |= VM_UFFD_MINOR; } - ret = validate_range(mm, uffdio_register.range.start, - uffdio_register.range.len); + ret = validate_range(mm, &uffdio_register.range); if (ret) goto out; @@ -1538,11 +1532,11 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, if (copy_from_user(&uffdio_unregister, buf, sizeof(uffdio_unregister))) goto out; - ret = validate_range(mm, uffdio_unregister.start, - uffdio_unregister.len); + ret = validate_range(mm, &uffdio_unregister); if (ret) goto out; + /* Get rid of start + end in favor of range *? */ start = uffdio_unregister.start; end = start + uffdio_unregister.len; @@ -1597,6 +1591,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, prev = vma_prev(&vmi); ret = 0; for_each_vma_range(vmi, vma, end) { + struct uffdio_range range; cond_resched(); BUG_ON(!vma_can_userfault(vma, vma->vm_flags)); @@ -1614,6 +1609,8 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, start = vma->vm_start; vma_end = min(end, vma->vm_end); + range.start = start; + range.len = vma_end - start; if (userfaultfd_missing(vma)) { /* * Wake any concurrent pending userfault while @@ -1621,15 +1618,12 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, * permanently and it avoids userland to call * UFFDIO_WAKE explicitly. */ - struct userfaultfd_wake_range range; - range.start = start; - range.len = vma_end - start; wake_userfault(vma->vm_userfaultfd_ctx.ctx, &range); } /* Reset ptes for the whole vma range if wr-protected */ if (userfaultfd_wp(vma)) - uffd_wp_range(vma, start, vma_end - start, false); + uffd_wp_range(vma, &range, false); new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS; prev = vma_merge(&vmi, mm, prev, start, vma_end, new_flags, @@ -1680,27 +1674,23 @@ static int userfaultfd_wake(struct userfaultfd_ctx *ctx, { int ret; struct uffdio_range uffdio_wake; - struct userfaultfd_wake_range range; const void __user *buf = (void __user *)arg; ret = -EFAULT; if (copy_from_user(&uffdio_wake, buf, sizeof(uffdio_wake))) goto out; - ret = validate_range(ctx->mm, uffdio_wake.start, uffdio_wake.len); + ret = validate_range(ctx->mm, &uffdio_wake); if (ret) goto out; - range.start = uffdio_wake.start; - range.len = uffdio_wake.len; - /* * len == 0 means wake all and we don't want to wake all here, * so check it again to be sure. */ - VM_BUG_ON(!range.len); + VM_BUG_ON(!uffdio_wake.len); - wake_userfault(ctx, &range); + wake_userfault(ctx, &uffdio_wake); ret = 0; out: @@ -1713,7 +1703,7 @@ static int userfaultfd_copy(struct userfaultfd_ctx *ctx, __s64 ret; struct uffdio_copy uffdio_copy; struct uffdio_copy __user *user_uffdio_copy; - struct userfaultfd_wake_range range; + struct uffdio_range range; int flags = 0; user_uffdio_copy = (struct uffdio_copy __user *) arg; @@ -1728,7 +1718,9 @@ static int userfaultfd_copy(struct userfaultfd_ctx *ctx, sizeof(uffdio_copy)-sizeof(__s64))) goto out; - ret = validate_range(ctx->mm, uffdio_copy.dst, uffdio_copy.len); + range.start = uffdio_copy.dst; + range.len = uffdio_copy.len; + ret = validate_range(ctx->mm, &range); if (ret) goto out; /* @@ -1744,9 +1736,8 @@ static int userfaultfd_copy(struct userfaultfd_ctx *ctx, if (uffdio_copy.mode & UFFDIO_COPY_MODE_WP) flags |= MFILL_ATOMIC_WP; if (mmget_not_zero(ctx->mm)) { - ret = mfill_atomic_copy(ctx->mm, uffdio_copy.dst, uffdio_copy.src, - uffdio_copy.len, &ctx->mmap_changing, - flags); + ret = mfill_atomic_copy(ctx->mm, uffdio_copy.src, &range, + &ctx->mmap_changing, flags); mmput(ctx->mm); } else { return -ESRCH; @@ -1758,10 +1749,8 @@ static int userfaultfd_copy(struct userfaultfd_ctx *ctx, BUG_ON(!ret); /* len == 0 would wake all */ range.len = ret; - if (!(uffdio_copy.mode & UFFDIO_COPY_MODE_DONTWAKE)) { - range.start = uffdio_copy.dst; + if (!(uffdio_copy.mode & UFFDIO_COPY_MODE_DONTWAKE)) wake_userfault(ctx, &range); - } ret = range.len == uffdio_copy.len ? 0 : -EAGAIN; out: return ret; @@ -1773,7 +1762,7 @@ static int userfaultfd_zeropage(struct userfaultfd_ctx *ctx, __s64 ret; struct uffdio_zeropage uffdio_zeropage; struct uffdio_zeropage __user *user_uffdio_zeropage; - struct userfaultfd_wake_range range; + struct uffdio_range range; user_uffdio_zeropage = (struct uffdio_zeropage __user *) arg; @@ -1787,8 +1776,8 @@ static int userfaultfd_zeropage(struct userfaultfd_ctx *ctx, sizeof(uffdio_zeropage)-sizeof(__s64))) goto out; - ret = validate_range(ctx->mm, uffdio_zeropage.range.start, - uffdio_zeropage.range.len); + range = uffdio_zeropage.range; + ret = validate_range(ctx->mm, &range); if (ret) goto out; ret = -EINVAL; @@ -1796,8 +1785,7 @@ static int userfaultfd_zeropage(struct userfaultfd_ctx *ctx, goto out; if (mmget_not_zero(ctx->mm)) { - ret = mfill_atomic_zeropage(ctx->mm, uffdio_zeropage.range.start, - uffdio_zeropage.range.len, + ret = mfill_atomic_zeropage(ctx->mm, &uffdio_zeropage.range, &ctx->mmap_changing); mmput(ctx->mm); } else { @@ -1811,7 +1799,6 @@ static int userfaultfd_zeropage(struct userfaultfd_ctx *ctx, BUG_ON(!ret); range.len = ret; if (!(uffdio_zeropage.mode & UFFDIO_ZEROPAGE_MODE_DONTWAKE)) { - range.start = uffdio_zeropage.range.start; wake_userfault(ctx, &range); } ret = range.len == uffdio_zeropage.range.len ? 0 : -EAGAIN; @@ -1825,7 +1812,6 @@ static int userfaultfd_writeprotect(struct userfaultfd_ctx *ctx, int ret; struct uffdio_writeprotect uffdio_wp; struct uffdio_writeprotect __user *user_uffdio_wp; - struct userfaultfd_wake_range range; bool mode_wp, mode_dontwake; if (atomic_read(&ctx->mmap_changing)) @@ -1837,8 +1823,7 @@ static int userfaultfd_writeprotect(struct userfaultfd_ctx *ctx, sizeof(struct uffdio_writeprotect))) return -EFAULT; - ret = validate_range(ctx->mm, uffdio_wp.range.start, - uffdio_wp.range.len); + ret = validate_range(ctx->mm, &uffdio_wp.range); if (ret) return ret; @@ -1853,9 +1838,8 @@ static int userfaultfd_writeprotect(struct userfaultfd_ctx *ctx, return -EINVAL; if (mmget_not_zero(ctx->mm)) { - ret = mwriteprotect_range(ctx->mm, uffdio_wp.range.start, - uffdio_wp.range.len, mode_wp, - &ctx->mmap_changing); + ret = mwriteprotect_range(ctx->mm, &uffdio_wp.range, + mode_wp, &ctx->mmap_changing); mmput(ctx->mm); } else { return -ESRCH; @@ -1864,11 +1848,8 @@ static int userfaultfd_writeprotect(struct userfaultfd_ctx *ctx, if (ret) return ret; - if (!mode_wp && !mode_dontwake) { - range.start = uffdio_wp.range.start; - range.len = uffdio_wp.range.len; - wake_userfault(ctx, &range); - } + if (!mode_wp && !mode_dontwake) + wake_userfault(ctx, &uffdio_wp.range); return ret; } @@ -1877,7 +1858,7 @@ static int userfaultfd_continue(struct userfaultfd_ctx *ctx, unsigned long arg) __s64 ret; struct uffdio_continue uffdio_continue; struct uffdio_continue __user *user_uffdio_continue; - struct userfaultfd_wake_range range; + struct uffdio_range range; user_uffdio_continue = (struct uffdio_continue __user *)arg; @@ -1891,23 +1872,20 @@ static int userfaultfd_continue(struct userfaultfd_ctx *ctx, unsigned long arg) sizeof(uffdio_continue) - (sizeof(__s64)))) goto out; - ret = validate_range(ctx->mm, uffdio_continue.range.start, - uffdio_continue.range.len); + range = uffdio_continue.range; + ret = validate_range(ctx->mm, &range); if (ret) goto out; ret = -EINVAL; /* double check for wraparound just in case. */ - if (uffdio_continue.range.start + uffdio_continue.range.len <= - uffdio_continue.range.start) { + if (range.start + range.len <= range.start) goto out; - } if (uffdio_continue.mode & ~UFFDIO_CONTINUE_MODE_DONTWAKE) goto out; if (mmget_not_zero(ctx->mm)) { - ret = mfill_atomic_continue(ctx->mm, uffdio_continue.range.start, - uffdio_continue.range.len, + ret = mfill_atomic_continue(ctx->mm, &range, &ctx->mmap_changing); mmput(ctx->mm); } else { @@ -1923,7 +1901,6 @@ static int userfaultfd_continue(struct userfaultfd_ctx *ctx, unsigned long arg) BUG_ON(!ret); range.len = ret; if (!(uffdio_continue.mode & UFFDIO_CONTINUE_MODE_DONTWAKE)) { - range.start = uffdio_continue.range.start; wake_userfault(ctx, &range); } ret = range.len == uffdio_continue.range.len ? 0 : -EAGAIN; diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h index a45c1b42e500..fcd95e3d3dcd 100644 --- a/include/linux/userfaultfd_k.h +++ b/include/linux/userfaultfd_k.h @@ -63,20 +63,21 @@ extern int mfill_atomic_install_pte(pmd_t *dst_pmd, unsigned long dst_addr, struct page *page, bool newly_allocated, uffd_flags_t flags); -extern ssize_t mfill_atomic_copy(struct mm_struct *dst_mm, unsigned long dst_start, - unsigned long src_start, unsigned long len, +extern ssize_t mfill_atomic_copy(struct mm_struct *dst_mm, unsigned long src_start, + const struct uffdio_range *dst, atomic_t *mmap_changing, uffd_flags_t flags); extern ssize_t mfill_atomic_zeropage(struct mm_struct *dst_mm, - unsigned long dst_start, - unsigned long len, + const struct uffdio_range *dst, atomic_t *mmap_changing); -extern ssize_t mfill_atomic_continue(struct mm_struct *dst_mm, unsigned long dst_start, - unsigned long len, atomic_t *mmap_changing); +extern ssize_t mfill_atomic_continue(struct mm_struct *dst_mm, + const struct uffdio_range *dst, + atomic_t *mmap_changing); extern int mwriteprotect_range(struct mm_struct *dst_mm, - unsigned long start, unsigned long len, + const struct uffdio_range *range, bool enable_wp, atomic_t *mmap_changing); extern long uffd_wp_range(struct vm_area_struct *vma, - unsigned long start, unsigned long len, bool enable_wp); + const struct uffdio_range *range, + bool enable_wp); /* mm helpers */ static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index c0d061acc069..870e7489e8d1 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -21,8 +21,7 @@ static __always_inline struct vm_area_struct *find_dst_vma(struct mm_struct *dst_mm, - unsigned long dst_start, - unsigned long len) + const struct uffdio_range *dst) { /* * Make sure that the dst range is both valid and fully within a @@ -30,12 +29,12 @@ struct vm_area_struct *find_dst_vma(struct mm_struct *dst_mm, */ struct vm_area_struct *dst_vma; - dst_vma = find_vma(dst_mm, dst_start); + dst_vma = find_vma(dst_mm, dst->start); if (!dst_vma) return NULL; - if (dst_start < dst_vma->vm_start || - dst_start + len > dst_vma->vm_end) + if (dst->start < dst_vma->vm_start || + dst->start + dst->len > dst_vma->vm_end) return NULL; /* @@ -309,9 +308,8 @@ static pmd_t *mm_alloc_pmd(struct mm_struct *mm, unsigned long address) */ static __always_inline ssize_t mfill_atomic_hugetlb( struct vm_area_struct *dst_vma, - unsigned long dst_start, unsigned long src_start, - unsigned long len, + const struct uffdio_range *dst, uffd_flags_t flags) { int mode = flags & MFILL_ATOMIC_MODE_MASK; @@ -339,7 +337,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb( } src_addr = src_start; - dst_addr = dst_start; + dst_addr = dst->start; copied = 0; page = NULL; vma_hpagesize = vma_kernel_pagesize(dst_vma); @@ -348,7 +346,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb( * Validate alignment based on huge page size */ err = -EINVAL; - if (dst_start & (vma_hpagesize - 1) || len & (vma_hpagesize - 1)) + if (dst->start & (vma_hpagesize - 1) || dst->len & (vma_hpagesize - 1)) goto out_unlock; retry: @@ -358,7 +356,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb( */ if (!dst_vma) { err = -ENOENT; - dst_vma = find_dst_vma(dst_mm, dst_start, len); + dst_vma = find_dst_vma(dst_mm, dst); if (!dst_vma || !is_vm_hugetlb_page(dst_vma)) goto out_unlock; @@ -378,8 +376,8 @@ static __always_inline ssize_t mfill_atomic_hugetlb( goto out_unlock; } - while (src_addr < src_start + len) { - BUG_ON(dst_addr >= dst_start + len); + while (src_addr < src_start + dst->len) { + BUG_ON(dst_addr >= dst->start + dst->len); /* * Serialize via vma_lock and hugetlb_fault_mutex. @@ -461,10 +459,9 @@ static __always_inline ssize_t mfill_atomic_hugetlb( #else /* !CONFIG_HUGETLB_PAGE */ /* fail at build time if gcc attempts to use this */ extern ssize_t mfill_atomic_hugetlb(struct vm_area_struct *dst_vma, - unsigned long dst_start, unsigned long src_start, - unsigned long len, - uffd_flags_t flags); + struct uffdio_range dst, + uffd_flags_t mode_flags); #endif /* CONFIG_HUGETLB_PAGE */ static __always_inline ssize_t mfill_atomic_pte(pmd_t *dst_pmd, @@ -510,9 +507,8 @@ static __always_inline ssize_t mfill_atomic_pte(pmd_t *dst_pmd, } static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm, - unsigned long dst_start, unsigned long src_start, - unsigned long len, + const struct uffdio_range *dst, atomic_t *mmap_changing, uffd_flags_t flags) { @@ -526,15 +522,15 @@ static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm, /* * Sanitize the command parameters: */ - BUG_ON(dst_start & ~PAGE_MASK); - BUG_ON(len & ~PAGE_MASK); + BUG_ON(dst->start & ~PAGE_MASK); + BUG_ON(dst->len & ~PAGE_MASK); /* Does the address range wrap, or is the span zero-sized? */ - BUG_ON(src_start + len <= src_start); - BUG_ON(dst_start + len <= dst_start); + BUG_ON(src_start + dst->len <= src_start); + BUG_ON(dst->start + dst->len <= dst->start); src_addr = src_start; - dst_addr = dst_start; + dst_addr = dst->start; copied = 0; page = NULL; retry: @@ -554,7 +550,7 @@ static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm, * both valid and fully within a single existing vma. */ err = -ENOENT; - dst_vma = find_dst_vma(dst_mm, dst_start, len); + dst_vma = find_dst_vma(dst_mm, dst); if (!dst_vma) goto out_unlock; @@ -578,8 +574,7 @@ static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm, * If this is a HUGETLB vma, pass off to appropriate routine */ if (is_vm_hugetlb_page(dst_vma)) - return mfill_atomic_hugetlb(dst_vma, dst_start, - src_start, len, flags); + return mfill_atomic_hugetlb(dst_vma, src_start, dst, flags); if (!vma_is_anonymous(dst_vma) && !vma_is_shmem(dst_vma)) goto out_unlock; @@ -597,10 +592,10 @@ static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm, unlikely(anon_vma_prepare(dst_vma))) goto out_unlock; - while (src_addr < src_start + len) { + while (src_addr < src_start + dst->len) { pmd_t dst_pmdval; - BUG_ON(dst_addr >= dst_start + len); + BUG_ON(dst_addr >= dst->start + dst->len); dst_pmd = mm_alloc_pmd(dst_mm, dst_addr); if (unlikely(!dst_pmd)) { @@ -678,30 +673,32 @@ static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm, return copied ? copied : err; } -ssize_t mfill_atomic_copy(struct mm_struct *dst_mm, unsigned long dst_start, - unsigned long src_start, unsigned long len, +ssize_t mfill_atomic_copy(struct mm_struct *dst_mm, unsigned long src_start, + const struct uffdio_range *dst, atomic_t *mmap_changing, uffd_flags_t flags) { - return mfill_atomic(dst_mm, dst_start, src_start, len, + return mfill_atomic(dst_mm, src_start, dst, mmap_changing, flags | MFILL_ATOMIC_COPY); } -ssize_t mfill_atomic_zeropage(struct mm_struct *dst_mm, unsigned long start, - unsigned long len, atomic_t *mmap_changing) +ssize_t mfill_atomic_zeropage(struct mm_struct *dst_mm, + const struct uffdio_range *dst, + atomic_t *mmap_changing) { - return mfill_atomic(dst_mm, start, 0, len, + return mfill_atomic(dst_mm, 0, dst, mmap_changing, MFILL_ATOMIC_ZEROPAGE); } -ssize_t mfill_atomic_continue(struct mm_struct *dst_mm, unsigned long start, - unsigned long len, atomic_t *mmap_changing) +ssize_t mfill_atomic_continue(struct mm_struct *dst_mm, + const struct uffdio_range *dst, + atomic_t *mmap_changing) { - return mfill_atomic(dst_mm, start, 0, len, + return mfill_atomic(dst_mm, 0, dst, mmap_changing, MFILL_ATOMIC_CONTINUE); } long uffd_wp_range(struct vm_area_struct *dst_vma, - unsigned long start, unsigned long len, bool enable_wp) + const struct uffdio_range *range, bool enable_wp) { unsigned int mm_cp_flags; struct mmu_gather tlb; @@ -721,15 +718,16 @@ long uffd_wp_range(struct vm_area_struct *dst_vma, if (!enable_wp && vma_wants_manual_pte_write_upgrade(dst_vma)) mm_cp_flags |= MM_CP_TRY_CHANGE_WRITABLE; tlb_gather_mmu(&tlb, dst_vma->vm_mm); - ret = change_protection(&tlb, dst_vma, start, start + len, mm_cp_flags); + ret = change_protection(&tlb, dst_vma, range->start, + range->start + range->len, mm_cp_flags); tlb_finish_mmu(&tlb); return ret; } -int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start, - unsigned long len, bool enable_wp, - atomic_t *mmap_changing) +int mwriteprotect_range(struct mm_struct *dst_mm, + const struct uffdio_range *dst, + bool enable_wp, atomic_t *mmap_changing) { struct vm_area_struct *dst_vma; unsigned long page_mask; @@ -738,11 +736,11 @@ int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start, /* * Sanitize the command parameters: */ - BUG_ON(start & ~PAGE_MASK); - BUG_ON(len & ~PAGE_MASK); + BUG_ON(dst->start & ~PAGE_MASK); + BUG_ON(dst->len & ~PAGE_MASK); /* Does the address range wrap, or is the span zero-sized? */ - BUG_ON(start + len <= start); + BUG_ON(dst->start + dst->len <= dst->start); mmap_read_lock(dst_mm); @@ -756,7 +754,7 @@ int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start, goto out_unlock; err = -ENOENT; - dst_vma = find_dst_vma(dst_mm, start, len); + dst_vma = find_dst_vma(dst_mm, dst); if (!dst_vma) goto out_unlock; @@ -768,11 +766,11 @@ int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start, if (is_vm_hugetlb_page(dst_vma)) { err = -EINVAL; page_mask = vma_kernel_pagesize(dst_vma) - 1; - if ((start & page_mask) || (len & page_mask)) + if ((dst->start & page_mask) || (dst->len & page_mask)) goto out_unlock; } - err = uffd_wp_range(dst_vma, start, len, enable_wp); + err = uffd_wp_range(dst_vma, dst, enable_wp); /* Return 0 on success, <0 on failures */ if (err > 0)
We have a lot of functions which take an address + length pair, currently passed as separate arguments. However, in our userspace API we already have struct uffdio_range, which is exactly this pair, and this is what we get from userspace when ioctls are called. Instead of splitting the struct up into two separate arguments, just plumb the struct through to the functions which use it (once we get to the mfill_atomic_pte level, we're dealing with single (huge)pages, so we don't need both parts). Relatedly, for waking, just re-use this existing structure instead of defining a new "struct uffdio_wake_range". Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> --- fs/userfaultfd.c | 107 +++++++++++++--------------------- include/linux/userfaultfd_k.h | 17 +++--- mm/userfaultfd.c | 92 ++++++++++++++--------------- 3 files changed, 96 insertions(+), 120 deletions(-)