| Message ID | 20190613094326.24093-11-hch@lst.de (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [01/22] mm: remove the unused ARCH_HAS_HMM_DEVICE Kconfig option | expand |
On 6/13/19 2:43 AM, Christoph Hellwig wrote: > This replaces the hacky ->fault callback, which is currently directly > called from common code through a hmm specific data structure as an > exercise in layering violations. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > include/linux/hmm.h | 6 ------ > include/linux/memremap.h | 6 ++++++ > include/linux/swapops.h | 15 --------------- > kernel/memremap.c | 31 ------------------------------- > mm/hmm.c | 13 +++++-------- > mm/memory.c | 9 ++------- > 6 files changed, 13 insertions(+), 67 deletions(-) > > diff --git a/include/linux/hmm.h b/include/linux/hmm.h > index 5761a39221a6..3c9a59dbfdb8 100644 > --- a/include/linux/hmm.h > +++ b/include/linux/hmm.h > @@ -658,11 +658,6 @@ struct hmm_devmem_ops { > * chunk, as an optimization. It must, however, prioritize the faulting address > * over all the others. > */ > -typedef vm_fault_t (*dev_page_fault_t)(struct vm_area_struct *vma, > - unsigned long addr, > - const struct page *page, > - unsigned int flags, > - pmd_t *pmdp); > > struct hmm_devmem { > struct completion completion; > @@ -673,7 +668,6 @@ struct hmm_devmem { > struct dev_pagemap pagemap; > const struct hmm_devmem_ops *ops; > struct percpu_ref ref; > - dev_page_fault_t page_fault; > }; > > /* > diff --git a/include/linux/memremap.h b/include/linux/memremap.h > index 96a3a6d564ad..03a4099be701 100644 > --- a/include/linux/memremap.h > +++ b/include/linux/memremap.h > @@ -75,6 +75,12 @@ struct dev_pagemap_ops { > * Transition the percpu_ref in struct dev_pagemap to the dead state. > */ > void (*kill)(struct dev_pagemap *pgmap); > + > + /* > + * Used for private (un-addressable) device memory only. Must migrate > + * the page back to a CPU accessible page. > + */ > + vm_fault_t (*migrate)(struct vm_fault *vmf); > }; > > /** > diff --git a/include/linux/swapops.h b/include/linux/swapops.h > index 4d961668e5fc..15bdb6fe71e5 100644 > --- a/include/linux/swapops.h > +++ b/include/linux/swapops.h > @@ -129,12 +129,6 @@ static inline struct page *device_private_entry_to_page(swp_entry_t entry) > { > return pfn_to_page(swp_offset(entry)); > } > - > -vm_fault_t device_private_entry_fault(struct vm_area_struct *vma, > - unsigned long addr, > - swp_entry_t entry, > - unsigned int flags, > - pmd_t *pmdp); > #else /* CONFIG_DEVICE_PRIVATE */ > static inline swp_entry_t make_device_private_entry(struct page *page, bool write) > { > @@ -164,15 +158,6 @@ static inline struct page *device_private_entry_to_page(swp_entry_t entry) > { > return NULL; > } > - > -static inline vm_fault_t device_private_entry_fault(struct vm_area_struct *vma, > - unsigned long addr, > - swp_entry_t entry, > - unsigned int flags, > - pmd_t *pmdp) > -{ > - return VM_FAULT_SIGBUS; > -} > #endif /* CONFIG_DEVICE_PRIVATE */ > > #ifdef CONFIG_MIGRATION > diff --git a/kernel/memremap.c b/kernel/memremap.c > index 6a3183cac764..7167e717647d 100644 > --- a/kernel/memremap.c > +++ b/kernel/memremap.c > @@ -11,7 +11,6 @@ > #include <linux/types.h> > #include <linux/wait_bit.h> > #include <linux/xarray.h> > -#include <linux/hmm.h> > > static DEFINE_XARRAY(pgmap_array); > #define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1) > @@ -48,36 +47,6 @@ static inline int dev_pagemap_enable(struct device *dev) > } > #endif /* CONFIG_DEV_PAGEMAP_OPS */ > > -#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) > -vm_fault_t device_private_entry_fault(struct vm_area_struct *vma, > - unsigned long addr, > - swp_entry_t entry, > - unsigned int flags, > - pmd_t *pmdp) > -{ > - struct page *page = device_private_entry_to_page(entry); > - struct hmm_devmem *devmem; > - > - devmem = container_of(page->pgmap, typeof(*devmem), pagemap); > - > - /* > - * The page_fault() callback must migrate page back to system memory > - * so that CPU can access it. This might fail for various reasons > - * (device issue, device was unsafely unplugged, ...). When such > - * error conditions happen, the callback must return VM_FAULT_SIGBUS. > - * > - * Note that because memory cgroup charges are accounted to the device > - * memory, this should never fail because of memory restrictions (but > - * allocation of regular system page might still fail because we are > - * out of memory). > - * > - * There is a more in-depth description of what that callback can and > - * cannot do, in include/linux/memremap.h > - */ > - return devmem->page_fault(vma, addr, page, flags, pmdp); > -} > -#endif /* CONFIG_DEVICE_PRIVATE */ > - > static void pgmap_array_delete(struct resource *res) > { > xa_store_range(&pgmap_array, PHYS_PFN(res->start), PHYS_PFN(res->end), > diff --git a/mm/hmm.c b/mm/hmm.c > index 6dc769feb2e1..aab799677c7d 100644 > --- a/mm/hmm.c > +++ b/mm/hmm.c > @@ -1330,15 +1330,12 @@ static void hmm_devmem_ref_kill(struct dev_pagemap *pgmap) > percpu_ref_kill(pgmap->ref); > } > > -static vm_fault_t hmm_devmem_fault(struct vm_area_struct *vma, > - unsigned long addr, > - const struct page *page, > - unsigned int flags, > - pmd_t *pmdp) > +static vm_fault_t hmm_devmem_migrate(struct vm_fault *vmf) > { > - struct hmm_devmem *devmem = page->pgmap->data; > + struct hmm_devmem *devmem = vmf->page->pgmap->data; > > - return devmem->ops->fault(devmem, vma, addr, page, flags, pmdp); > + return devmem->ops->fault(devmem, vmf->vma, vmf->address, vmf->page, > + vmf->flags, vmf->pmd); > } > > static void hmm_devmem_free(struct page *page, void *data) > @@ -1351,6 +1348,7 @@ static void hmm_devmem_free(struct page *page, void *data) > static const struct dev_pagemap_ops hmm_pagemap_ops = { > .page_free = hmm_devmem_free, > .kill = hmm_devmem_ref_kill, > + .migrate = hmm_devmem_migrate, > }; > > /* > @@ -1405,7 +1403,6 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops, > devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT; > devmem->pfn_last = devmem->pfn_first + > (resource_size(devmem->resource) >> PAGE_SHIFT); > - devmem->page_fault = hmm_devmem_fault; > > devmem->pagemap.type = MEMORY_DEVICE_PRIVATE; > devmem->pagemap.res = *devmem->resource; > diff --git a/mm/memory.c b/mm/memory.c > index ddf20bd0c317..cbf3cb598436 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -2782,13 +2782,8 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) > migration_entry_wait(vma->vm_mm, vmf->pmd, > vmf->address); > } else if (is_device_private_entry(entry)) { > - /* > - * For un-addressable device memory we call the pgmap > - * fault handler callback. The callback must migrate > - * the page back to some CPU accessible page. > - */ > - ret = device_private_entry_fault(vma, vmf->address, entry, > - vmf->flags, vmf->pmd); > + vmf->page = device_private_entry_to_page(entry); > + ret = page->pgmap->ops->migrate(vmf); This needs to either initialize "page" or be changed to "vmf->page". Otherwise, it is a NULL pointer dereference. > } else if (is_hwpoison_entry(entry)) { > ret = VM_FAULT_HWPOISON; > } else { > You can add: Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
On Thu, Jun 13, 2019 at 04:42:07PM -0700, Ralph Campbell wrote: > This needs to either initialize "page" or be changed to "vmf->page". > Otherwise, it is a NULL pointer dereference. Thanks, fixed.
diff --git a/include/linux/hmm.h b/include/linux/hmm.h index 5761a39221a6..3c9a59dbfdb8 100644 --- a/include/linux/hmm.h +++ b/include/linux/hmm.h @@ -658,11 +658,6 @@ struct hmm_devmem_ops { * chunk, as an optimization. It must, however, prioritize the faulting address * over all the others. */ -typedef vm_fault_t (*dev_page_fault_t)(struct vm_area_struct *vma, - unsigned long addr, - const struct page *page, - unsigned int flags, - pmd_t *pmdp); struct hmm_devmem { struct completion completion; @@ -673,7 +668,6 @@ struct hmm_devmem { struct dev_pagemap pagemap; const struct hmm_devmem_ops *ops; struct percpu_ref ref; - dev_page_fault_t page_fault; }; /* diff --git a/include/linux/memremap.h b/include/linux/memremap.h index 96a3a6d564ad..03a4099be701 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -75,6 +75,12 @@ struct dev_pagemap_ops { * Transition the percpu_ref in struct dev_pagemap to the dead state. */ void (*kill)(struct dev_pagemap *pgmap); + + /* + * Used for private (un-addressable) device memory only. Must migrate + * the page back to a CPU accessible page. + */ + vm_fault_t (*migrate)(struct vm_fault *vmf); }; /** diff --git a/include/linux/swapops.h b/include/linux/swapops.h index 4d961668e5fc..15bdb6fe71e5 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -129,12 +129,6 @@ static inline struct page *device_private_entry_to_page(swp_entry_t entry) { return pfn_to_page(swp_offset(entry)); } - -vm_fault_t device_private_entry_fault(struct vm_area_struct *vma, - unsigned long addr, - swp_entry_t entry, - unsigned int flags, - pmd_t *pmdp); #else /* CONFIG_DEVICE_PRIVATE */ static inline swp_entry_t make_device_private_entry(struct page *page, bool write) { @@ -164,15 +158,6 @@ static inline struct page *device_private_entry_to_page(swp_entry_t entry) { return NULL; } - -static inline vm_fault_t device_private_entry_fault(struct vm_area_struct *vma, - unsigned long addr, - swp_entry_t entry, - unsigned int flags, - pmd_t *pmdp) -{ - return VM_FAULT_SIGBUS; -} #endif /* CONFIG_DEVICE_PRIVATE */ #ifdef CONFIG_MIGRATION diff --git a/kernel/memremap.c b/kernel/memremap.c index 6a3183cac764..7167e717647d 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -11,7 +11,6 @@ #include <linux/types.h> #include <linux/wait_bit.h> #include <linux/xarray.h> -#include <linux/hmm.h> static DEFINE_XARRAY(pgmap_array); #define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1) @@ -48,36 +47,6 @@ static inline int dev_pagemap_enable(struct device *dev) } #endif /* CONFIG_DEV_PAGEMAP_OPS */ -#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) -vm_fault_t device_private_entry_fault(struct vm_area_struct *vma, - unsigned long addr, - swp_entry_t entry, - unsigned int flags, - pmd_t *pmdp) -{ - struct page *page = device_private_entry_to_page(entry); - struct hmm_devmem *devmem; - - devmem = container_of(page->pgmap, typeof(*devmem), pagemap); - - /* - * The page_fault() callback must migrate page back to system memory - * so that CPU can access it. This might fail for various reasons - * (device issue, device was unsafely unplugged, ...). When such - * error conditions happen, the callback must return VM_FAULT_SIGBUS. - * - * Note that because memory cgroup charges are accounted to the device - * memory, this should never fail because of memory restrictions (but - * allocation of regular system page might still fail because we are - * out of memory). - * - * There is a more in-depth description of what that callback can and - * cannot do, in include/linux/memremap.h - */ - return devmem->page_fault(vma, addr, page, flags, pmdp); -} -#endif /* CONFIG_DEVICE_PRIVATE */ - static void pgmap_array_delete(struct resource *res) { xa_store_range(&pgmap_array, PHYS_PFN(res->start), PHYS_PFN(res->end), diff --git a/mm/hmm.c b/mm/hmm.c index 6dc769feb2e1..aab799677c7d 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -1330,15 +1330,12 @@ static void hmm_devmem_ref_kill(struct dev_pagemap *pgmap) percpu_ref_kill(pgmap->ref); } -static vm_fault_t hmm_devmem_fault(struct vm_area_struct *vma, - unsigned long addr, - const struct page *page, - unsigned int flags, - pmd_t *pmdp) +static vm_fault_t hmm_devmem_migrate(struct vm_fault *vmf) { - struct hmm_devmem *devmem = page->pgmap->data; + struct hmm_devmem *devmem = vmf->page->pgmap->data; - return devmem->ops->fault(devmem, vma, addr, page, flags, pmdp); + return devmem->ops->fault(devmem, vmf->vma, vmf->address, vmf->page, + vmf->flags, vmf->pmd); } static void hmm_devmem_free(struct page *page, void *data) @@ -1351,6 +1348,7 @@ static void hmm_devmem_free(struct page *page, void *data) static const struct dev_pagemap_ops hmm_pagemap_ops = { .page_free = hmm_devmem_free, .kill = hmm_devmem_ref_kill, + .migrate = hmm_devmem_migrate, }; /* @@ -1405,7 +1403,6 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops, devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT; devmem->pfn_last = devmem->pfn_first + (resource_size(devmem->resource) >> PAGE_SHIFT); - devmem->page_fault = hmm_devmem_fault; devmem->pagemap.type = MEMORY_DEVICE_PRIVATE; devmem->pagemap.res = *devmem->resource; diff --git a/mm/memory.c b/mm/memory.c index ddf20bd0c317..cbf3cb598436 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2782,13 +2782,8 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) migration_entry_wait(vma->vm_mm, vmf->pmd, vmf->address); } else if (is_device_private_entry(entry)) { - /* - * For un-addressable device memory we call the pgmap - * fault handler callback. The callback must migrate - * the page back to some CPU accessible page. - */ - ret = device_private_entry_fault(vma, vmf->address, entry, - vmf->flags, vmf->pmd); + vmf->page = device_private_entry_to_page(entry); + ret = page->pgmap->ops->migrate(vmf); } else if (is_hwpoison_entry(entry)) { ret = VM_FAULT_HWPOISON; } else {
This replaces the hacky ->fault callback, which is currently directly called from common code through a hmm specific data structure as an exercise in layering violations. Signed-off-by: Christoph Hellwig <hch@lst.de> --- include/linux/hmm.h | 6 ------ include/linux/memremap.h | 6 ++++++ include/linux/swapops.h | 15 --------------- kernel/memremap.c | 31 ------------------------------- mm/hmm.c | 13 +++++-------- mm/memory.c | 9 ++------- 6 files changed, 13 insertions(+), 67 deletions(-)