| Message ID | 152815391576.39010.14402839848074832654.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon 04-06-18 16:11:55, Dan Williams wrote: > In support of enabling memory_failure() handling for device-dax > mappings, set the ->mapping association of pages backing device-dax > mappings. The rmap implementation requires page_mapping() to return the > address_space hosting the vmas that map the page. > > The ->mapping pointer is never cleared. There is no possibility for the > page to become associated with another address_space while the device is > enabled. When the device is disabled the 'struct page' array for the > device is destroyed / later reinitialized to zero. > > Signed-off-by: Dan Williams <dan.j.williams@intel.com> Looks good to me. You can add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > drivers/dax/device.c | 55 +++++++++++++++++++++++++++++++++++--------------- > 1 file changed, 38 insertions(+), 17 deletions(-) > > diff --git a/drivers/dax/device.c b/drivers/dax/device.c > index 686de08e120b..7ec246549721 100644 > --- a/drivers/dax/device.c > +++ b/drivers/dax/device.c > @@ -245,13 +245,12 @@ __weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff, > } > > static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax, > - struct vm_fault *vmf) > + struct vm_fault *vmf, pfn_t *pfn) > { > struct vm_area_struct *vma = vmf->vma; > struct device *dev = &dev_dax->dev; > struct dax_region *dax_region; > phys_addr_t phys; > - pfn_t pfn; > unsigned int fault_size = PAGE_SIZE; > > if (check_vma(dev_dax, vma, __func__)) > @@ -273,13 +272,13 @@ static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax, > return VM_FAULT_SIGBUS; > } > > - pfn = phys_to_pfn_t(phys, dax_region->pfn_flags); > + *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags); > > - return vmf_insert_mixed(vma, vmf->address, pfn); > + return vmf_insert_mixed(vma, vmf->address, *pfn); > } > > static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax, > - struct vm_fault *vmf) > + struct vm_fault *vmf, pfn_t *pfn) > { > unsigned long pmd_addr = vmf->address & PMD_MASK; > struct vm_area_struct *vma = vmf->vma; > @@ -287,7 +286,6 @@ static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax, > struct dax_region *dax_region; > phys_addr_t phys; > pgoff_t pgoff; > - pfn_t pfn; > unsigned int fault_size = PMD_SIZE; > > if (check_vma(dev_dax, vma, __func__)) > @@ -322,15 +320,15 @@ static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax, > return VM_FAULT_SIGBUS; > } > > - pfn = phys_to_pfn_t(phys, dax_region->pfn_flags); > + *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags); > > - return vmf_insert_pfn_pmd(vma, vmf->address, vmf->pmd, pfn, > + return vmf_insert_pfn_pmd(vma, vmf->address, vmf->pmd, *pfn, > vmf->flags & FAULT_FLAG_WRITE); > } > > #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD > static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, > - struct vm_fault *vmf) > + struct vm_fault *vmf, pfn_t *pfn) > { > unsigned long pud_addr = vmf->address & PUD_MASK; > struct vm_area_struct *vma = vmf->vma; > @@ -338,7 +336,6 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, > struct dax_region *dax_region; > phys_addr_t phys; > pgoff_t pgoff; > - pfn_t pfn; > unsigned int fault_size = PUD_SIZE; > > > @@ -374,14 +371,14 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, > return VM_FAULT_SIGBUS; > } > > - pfn = phys_to_pfn_t(phys, dax_region->pfn_flags); > + *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags); > > - return vmf_insert_pfn_pud(vma, vmf->address, vmf->pud, pfn, > + return vmf_insert_pfn_pud(vma, vmf->address, vmf->pud, *pfn, > vmf->flags & FAULT_FLAG_WRITE); > } > #else > static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, > - struct vm_fault *vmf) > + struct vm_fault *vmf, pfn_t *pfn) > { > return VM_FAULT_FALLBACK; > } > @@ -390,9 +387,11 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, > static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf, > enum page_entry_size pe_size) > { > - int rc, id; > struct vm_area_struct *vma = vmf->vma; > struct file *filp = vma->vm_file; > + unsigned long fault_size; > + int rc, id; > + pfn_t pfn; > struct dev_dax *dev_dax = filp->private_data; > > dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) size = %d\n", current->comm, > @@ -402,17 +401,39 @@ static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf, > id = dax_read_lock(); > switch (pe_size) { > case PE_SIZE_PTE: > - rc = __dev_dax_pte_fault(dev_dax, vmf); > + fault_size = PAGE_SIZE; > + rc = __dev_dax_pte_fault(dev_dax, vmf, &pfn); > break; > case PE_SIZE_PMD: > - rc = __dev_dax_pmd_fault(dev_dax, vmf); > + fault_size = PMD_SIZE; > + rc = __dev_dax_pmd_fault(dev_dax, vmf, &pfn); > break; > case PE_SIZE_PUD: > - rc = __dev_dax_pud_fault(dev_dax, vmf); > + fault_size = PUD_SIZE; > + rc = __dev_dax_pud_fault(dev_dax, vmf, &pfn); > break; > default: > rc = VM_FAULT_SIGBUS; > } > + > + if (rc == VM_FAULT_NOPAGE) { > + unsigned long i; > + > + /* > + * In the device-dax case the only possibility for a > + * VM_FAULT_NOPAGE result is when device-dax capacity is > + * mapped. No need to consider the zero page, or racing > + * conflicting mappings. > + */ > + for (i = 0; i < fault_size / PAGE_SIZE; i++) { > + struct page *page; > + > + page = pfn_to_page(pfn_t_to_pfn(pfn) + i); > + if (page->mapping) > + continue; > + page->mapping = filp->f_mapping; > + } > + } > dax_read_unlock(id); > > return rc; >
diff --git a/drivers/dax/device.c b/drivers/dax/device.c index 686de08e120b..7ec246549721 100644 --- a/drivers/dax/device.c +++ b/drivers/dax/device.c @@ -245,13 +245,12 @@ __weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff, } static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax, - struct vm_fault *vmf) + struct vm_fault *vmf, pfn_t *pfn) { struct vm_area_struct *vma = vmf->vma; struct device *dev = &dev_dax->dev; struct dax_region *dax_region; phys_addr_t phys; - pfn_t pfn; unsigned int fault_size = PAGE_SIZE; if (check_vma(dev_dax, vma, __func__)) @@ -273,13 +272,13 @@ static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax, return VM_FAULT_SIGBUS; } - pfn = phys_to_pfn_t(phys, dax_region->pfn_flags); + *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags); - return vmf_insert_mixed(vma, vmf->address, pfn); + return vmf_insert_mixed(vma, vmf->address, *pfn); } static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax, - struct vm_fault *vmf) + struct vm_fault *vmf, pfn_t *pfn) { unsigned long pmd_addr = vmf->address & PMD_MASK; struct vm_area_struct *vma = vmf->vma; @@ -287,7 +286,6 @@ static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax, struct dax_region *dax_region; phys_addr_t phys; pgoff_t pgoff; - pfn_t pfn; unsigned int fault_size = PMD_SIZE; if (check_vma(dev_dax, vma, __func__)) @@ -322,15 +320,15 @@ static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax, return VM_FAULT_SIGBUS; } - pfn = phys_to_pfn_t(phys, dax_region->pfn_flags); + *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags); - return vmf_insert_pfn_pmd(vma, vmf->address, vmf->pmd, pfn, + return vmf_insert_pfn_pmd(vma, vmf->address, vmf->pmd, *pfn, vmf->flags & FAULT_FLAG_WRITE); } #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, - struct vm_fault *vmf) + struct vm_fault *vmf, pfn_t *pfn) { unsigned long pud_addr = vmf->address & PUD_MASK; struct vm_area_struct *vma = vmf->vma; @@ -338,7 +336,6 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, struct dax_region *dax_region; phys_addr_t phys; pgoff_t pgoff; - pfn_t pfn; unsigned int fault_size = PUD_SIZE; @@ -374,14 +371,14 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, return VM_FAULT_SIGBUS; } - pfn = phys_to_pfn_t(phys, dax_region->pfn_flags); + *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags); - return vmf_insert_pfn_pud(vma, vmf->address, vmf->pud, pfn, + return vmf_insert_pfn_pud(vma, vmf->address, vmf->pud, *pfn, vmf->flags & FAULT_FLAG_WRITE); } #else static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, - struct vm_fault *vmf) + struct vm_fault *vmf, pfn_t *pfn) { return VM_FAULT_FALLBACK; } @@ -390,9 +387,11 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf, enum page_entry_size pe_size) { - int rc, id; struct vm_area_struct *vma = vmf->vma; struct file *filp = vma->vm_file; + unsigned long fault_size; + int rc, id; + pfn_t pfn; struct dev_dax *dev_dax = filp->private_data; dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) size = %d\n", current->comm, @@ -402,17 +401,39 @@ static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf, id = dax_read_lock(); switch (pe_size) { case PE_SIZE_PTE: - rc = __dev_dax_pte_fault(dev_dax, vmf); + fault_size = PAGE_SIZE; + rc = __dev_dax_pte_fault(dev_dax, vmf, &pfn); break; case PE_SIZE_PMD: - rc = __dev_dax_pmd_fault(dev_dax, vmf); + fault_size = PMD_SIZE; + rc = __dev_dax_pmd_fault(dev_dax, vmf, &pfn); break; case PE_SIZE_PUD: - rc = __dev_dax_pud_fault(dev_dax, vmf); + fault_size = PUD_SIZE; + rc = __dev_dax_pud_fault(dev_dax, vmf, &pfn); break; default: rc = VM_FAULT_SIGBUS; } + + if (rc == VM_FAULT_NOPAGE) { + unsigned long i; + + /* + * In the device-dax case the only possibility for a + * VM_FAULT_NOPAGE result is when device-dax capacity is + * mapped. No need to consider the zero page, or racing + * conflicting mappings. + */ + for (i = 0; i < fault_size / PAGE_SIZE; i++) { + struct page *page; + + page = pfn_to_page(pfn_t_to_pfn(pfn) + i); + if (page->mapping) + continue; + page->mapping = filp->f_mapping; + } + } dax_read_unlock(id); return rc;
In support of enabling memory_failure() handling for device-dax mappings, set the ->mapping association of pages backing device-dax mappings. The rmap implementation requires page_mapping() to return the address_space hosting the vmas that map the page. The ->mapping pointer is never cleared. There is no possibility for the page to become associated with another address_space while the device is enabled. When the device is disabled the 'struct page' array for the device is destroyed / later reinitialized to zero. Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- drivers/dax/device.c | 55 +++++++++++++++++++++++++++++++++++--------------- 1 file changed, 38 insertions(+), 17 deletions(-)