search for: mmu_range_read_begin

...ct mm_struct *mm; +}; + #ifdef CONFIG_MMU_NOTIFIER #ifdef CONFIG_LOCKDEP @@ -263,6 +289,78 @@ extern int __mmu_notifier_register(struct mmu_notifier *mn, struct mm_struct *mm); extern void mmu_notifier_unregister(struct mmu_notifier *mn, struct mm_struct *mm); + +unsigned long mmu_range_read_begin(struct mmu_range_notifier *mrn); +int mmu_range_notifier_insert(struct mmu_range_notifier *mrn, + unsigned long start, unsigned long length, + struct mm_struct *mm); +int mmu_range_notifier_insert_locked(struct mmu_range_notifier *mrn, + unsigned long start, unsigned long le...

...MU_NOTIFIER > > #ifdef CONFIG_LOCKDEP > @@ -263,6 +289,78 @@ extern int __mmu_notifier_register(struct mmu_notifier *mn, > struct mm_struct *mm); > extern void mmu_notifier_unregister(struct mmu_notifier *mn, > struct mm_struct *mm); > + > +unsigned long mmu_range_read_begin(struct mmu_range_notifier *mrn); > +int mmu_range_notifier_insert(struct mmu_range_notifier *mrn, > + unsigned long start, unsigned long length, > + struct mm_struct *mm); > +int mmu_range_notifier_insert_locked(struct mmu_range_notifier *mrn, > + unsigned lon...

...ly from the invalidate callback of a > > + * struct mmu_range_notifier_ops under the same lock that is used to call > > + * mmu_range_read_retry(). It updates the sequence number for later use by > > + * mmu_range_read_retry(). > > + * > > + * If the user does not call mmu_range_read_begin() or mmu_range_read_retry() > > nit: "caller" is better than "user", when referring to...well, callers. "user" > most often refers to user space, whereas a call stack and function calling is > clearly what you're referring to here (and in other place...

...commented in v1 about rtnl_lock() being something network people only might be familiar, i think i saw it documented somewhere, maybe a lwn article. But if you are familiar with network it is a think well understood ... for any reasonable network scholar ;) > ... > > > +unsigned long mmu_range_read_begin(struct mmu_range_notifier *mrn) > > +{ > > + struct mmu_notifier_mm *mmn_mm = mrn->mm->mmu_notifier_mm; > > + unsigned long seq; > > + bool is_invalidating; > > + > > + /* > > + * If the mrn has a different seq value under the user_lock than we >...

...t mmu_range_notifier_ops under the same lock that is used to call > * mmu_range_read_retry(). It updates the sequence number for later use by > - * mmu_range_read_retry(). > + * mmu_range_read_retry(). The provided cur_seq will always be odd. > * > - * If the user does not call mmu_range_read_begin() or mmu_range_read_retry() > - * then this call is not required. > + * If the caller does not call mmu_range_read_begin() or > + * mmu_range_read_retry() then this call is not required. > */ > static inline void mmu_range_set_seq(struct mmu_range_notifier *mrn, >...

From: Jason Gunthorpe <jgg at mellanox.com> 8 of the mmu_notifier using drivers (i915_gem, radeon_mn, umem_odp, hfi1, scif_dma, vhost, gntdev, hmm) drivers are using a common pattern where they only use invalidate_range_start/end and immediately check the invalidating range against some driver data structure to tell if the driver is interested. Half of them use an interval_tree, the others

...ret = mmu_range_notifier_insert(&bo->notifier, addr, radeon_bo_size(bo), + current->mm); + if (ret) + return ret; + + /* + * FIXME: radeon appears to allow get_user_pages to run during + * invalidate_range_start/end, which is not a safe way to read the + * PTEs. It should use the mmu_range_read_begin() scheme around the + * get_user_pages to ensure that the PTEs are read properly + */ + mmu_range_read_begin(&bo->notifier); return 0; } @@ -231,27 +121,8 @@ int radeon_mn_register(struct radeon_bo *bo, unsigned long addr) */ void radeon_mn_unregister(struct radeon_bo *bo) { - str...

...->notifier, addr, radeon_bo_size(bo), > + current->mm); > + if (ret) > + return ret; > + > + /* > + * FIXME: radeon appears to allow get_user_pages to run during > + * invalidate_range_start/end, which is not a safe way to read the > + * PTEs. It should use the mmu_range_read_begin() scheme around the > + * get_user_pages to ensure that the PTEs are read properly > + */ > + mmu_range_read_begin(&bo->notifier); > return 0; > } > > @@ -231,27 +121,8 @@ int radeon_mn_register(struct radeon_bo *bo, unsigned long addr) > */ > void r...

...3,20 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages) > r = -EPERM; > goto out_unlock; > } > + up_read(&mm->mmap_sem); > + timeout = jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); > + > +retry: > + range->notifier_seq = mmu_range_read_begin(&bo->notifier); > > + down_read(&mm->mmap_sem); > r = hmm_range_fault(range, 0); > up_read(&mm->mmap_sem); > - > - if (unlikely(r < 0)) > + if (unlikely(r <= 0)) { > + if ((r == 0 || r == -EBUSY) && !time_after(jiffies, timeout)) &gt...

...3,20 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages) > r = -EPERM; > goto out_unlock; > } > + up_read(&mm->mmap_sem); > + timeout = jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); > + > +retry: > + range->notifier_seq = mmu_range_read_begin(&bo->notifier); > > + down_read(&mm->mmap_sem); > r = hmm_range_fault(range, 0); > up_read(&mm->mmap_sem); > - > - if (unlikely(r < 0)) > + if (unlikely(r <= 0)) { > + if ((r == 0 || r == -EBUSY) && !time_after(jiffies, timeout)) &gt...

On Tue, Oct 29, 2019 at 07:22:37PM +0000, Yang, Philip wrote: > Hi Jason, > > I did quick test after merging amd-staging-drm-next with the > mmu_notifier branch, which includes this set changes. The test result > has different failures, app stuck intermittently, GUI no display etc. I > am understanding the changes and will try to figure out the cause. Thanks! I'm not

...pages(struct amdgpu_bo *bo, struct page **pages) >> r = -EPERM; >> goto out_unlock; >> } >> + up_read(&mm->mmap_sem); >> + timeout = jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); >> + >> +retry: >> + range->notifier_seq = mmu_range_read_begin(&bo->notifier); >> >> + down_read(&mm->mmap_sem); >> r = hmm_range_fault(range, 0); >> up_read(&mm->mmap_sem); >> - >> - if (unlikely(r < 0)) >> + if (unlikely(r <= 0)) { >> + if ((r == 0 || r == -EBUSY) &&...

...;default_flags = 0; - range->pfn_flags_mask = -1UL; + while (true) { + if (time_after(jiffies, timeout)) + return -EBUSY; - ret = hmm_range_register(range, &svmm->mirror); - if (ret) { - up_read(&svmm->notifier.mm->mmap_sem); - return (int)ret; - } + range.notifier_seq = mmu_range_read_begin(range.notifier); + range.default_flags = 0; + range.pfn_flags_mask = -1UL; + down_read(&mm->mmap_sem); + ret = hmm_range_fault(&range, 0); + up_read(&mm->mmap_sem); + if (ret <= 0) { + if (ret == 0 || ret == -EBUSY) + continue; + return ret; + } - if (!hmm_range...

...notifier is to prevent the hypervisor pointer to the PTE from > + * going stale. > + * > + * Since this vma's mappings can't be touched without the mmap_sem, > + * and we are holding it now, there is no need for the notifier_range > + * locking pattern. > + */ > + mmu_range_read_begin(&map->notifier); > + > if (use_ptemod) { > map->pages_vm_start = vma->vm_start; > err = apply_to_page_range(vma->vm_mm, vma->vm_start, > @@ -1175,8 +1088,11 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) > mutex_unlock(&pr...

...ge_notifier_insert( + &node->notifier, tbuf->vaddr + (pageidx * PAGE_SIZE), + npages * PAGE_SIZE, fd->mm); + if (ret) + goto out_unmap; + /* + * FIXME: This is in the wrong order, the notifier should be + * established before the pages are pinned by pin_rcv_pages. + */ + mmu_range_read_begin(&node->notifier); } + fd->entry_to_rb[node->rcventry - uctxt->expected_base] = node; + hfi1_put_tid(dd, rcventry, PT_EXPECTED, phys, ilog2(npages) + 1); trace_hfi1_exp_tid_reg(uctxt->ctxt, fd->subctxt, rcventry, npages, - node->mmu.addr, node->phys, phys);...

...t_pages(). The purpose of + * the notifier is to prevent the hypervisor pointer to the PTE from + * going stale. + * + * Since this vma's mappings can't be touched without the mmap_sem, + * and we are holding it now, there is no need for the notifier_range + * locking pattern. + */ + mmu_range_read_begin(&map->notifier); + if (use_ptemod) { map->pages_vm_start = vma->vm_start; err = apply_to_page_range(vma->vm_mm, vma->vm_start, @@ -1175,8 +1088,11 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) mutex_unlock(&priv->lock); out_put_map:...

...or range to be valid, safe to ignore return value as we > - * will use the return value of hmm_range_fault() below under the > - * mmap_sem to ascertain the validity of the range. > - */ > - hmm_range_wait_until_valid(range, HMM_RANGE_DEFAULT_TIMEOUT); > + range->notifier_seq = mmu_range_read_begin(&bo->notifier); > > down_read(&mm->mmap_sem); > vma = find_vma(mm, start); > @@ -855,10 +861,10 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages) > goto out_free_pfns; > > for (i = 0; i < ttm->num_pages; i++) {...

...; - - /* - * Just wait for range to be valid, safe to ignore return value as we - * will use the return value of hmm_range_fault() below under the - * mmap_sem to ascertain the validity of the range. - */ - hmm_range_wait_until_valid(range, HMM_RANGE_DEFAULT_TIMEOUT); + range->notifier_seq = mmu_range_read_begin(&bo->notifier); down_read(&mm->mmap_sem); vma = find_vma(mm, start); @@ -855,10 +861,10 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages) goto out_free_pfns; for (i = 0; i < ttm->num_pages; i++) { - pages[i] = hmm_device_entry_to_page(r...