Re: [Nouveau] [PATCH 10/22] memremap: add a migrate callback to struct dev_pagemap_ops
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. ___ Nouveau mailing list Nouveau@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/nouveau
Re: [PATCH 10/22] memremap: add a migrate callback to struct dev_pagemap_ops
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
---
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_tpage_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
#include
#include
-#include
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 */
-
[Nouveau] [PATCH 10/22] memremap: add a migrate callback to struct dev_pagemap_ops
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
---
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_tpage_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
#include
#include
-#include
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(_array,
