[patch 6/7] mm: merge nopfn into fault
Remove ->nopfn and reimplement the only existing handler using ->fault
Signed-off-by: Nick Piggin <[EMAIL PROTECTED]>
Index: linux-2.6/drivers/char/mspec.c
===
--- linux-2.6.orig/drivers/char/mspec.c
+++ linux-2.6/drivers/char/mspec.c
@@ -182,24 +182,25 @@ mspec_close(struct vm_area_struct *vma)
/*
- * mspec_nopfn
+ * mspec_fault
*
* Creates a mspec page and maps it to user space.
*/
-static unsigned long
-mspec_nopfn(struct vm_area_struct *vma, unsigned long address)
+static struct page *
+mspec_fault(struct fault_data *fdata)
{
unsigned long paddr, maddr;
unsigned long pfn;
- int index;
- struct vma_data *vdata = vma->vm_private_data;
+ int index = fdata->pgoff;
+ struct vma_data *vdata = fdata->vma->vm_private_data;
- index = (address - vma->vm_start) >> PAGE_SHIFT;
maddr = (volatile unsigned long) vdata->maddr[index];
if (maddr == 0) {
maddr = uncached_alloc_page(numa_node_id());
- if (maddr == 0)
- return NOPFN_OOM;
+ if (maddr == 0) {
+ fdata->type = VM_FAULT_OOM;
+ return NULL;
+ }
spin_lock(>lock);
if (vdata->maddr[index] == 0) {
@@ -219,13 +220,21 @@ mspec_nopfn(struct vm_area_struct *vma,
pfn = paddr >> PAGE_SHIFT;
- return pfn;
+ fdata->type = VM_FAULT_MINOR;
+ /*
+* vm_insert_pfn can fail with -EBUSY, but in that case it will
+* be because another thread has installed the pte first, so it
+* is no problem.
+*/
+ vm_insert_pfn(fdata->vma, fdata->address, pfn);
+
+ return NULL;
}
static struct vm_operations_struct mspec_vm_ops = {
.open = mspec_open,
.close = mspec_close,
- .nopfn = mspec_nopfn
+ .fault = mspec_fault,
};
/*
Index: linux-2.6/include/linux/mm.h
===
--- linux-2.6.orig/include/linux/mm.h
+++ linux-2.6/include/linux/mm.h
@@ -228,7 +228,6 @@ struct vm_operations_struct {
void (*close)(struct vm_area_struct * area);
struct page * (*fault)(struct vm_area_struct *vma, struct fault_data *
fdata);
struct page * (*nopage)(struct vm_area_struct * area, unsigned long
address, int *type);
- unsigned long (*nopfn)(struct vm_area_struct * area, unsigned long
address);
int (*populate)(struct vm_area_struct * area, unsigned long address,
unsigned long len, pgprot_t prot, unsigned long pgoff, int nonblock);
/* notification that a previously read-only page is about to become
@@ -659,12 +658,6 @@ static inline int page_mapped(struct pag
#define NOPAGE_OOM ((struct page *) (-1))
/*
- * Error return values for the *_nopfn functions
- */
-#define NOPFN_SIGBUS ((unsigned long) -1)
-#define NOPFN_OOM ((unsigned long) -2)
-
-/*
* Different kinds of faults, as returned by handle_mm_fault().
* Used to decide whether a process gets delivered SIGBUS or
* just gets major/minor fault counters bumped up.
Index: linux-2.6/mm/memory.c
===
--- linux-2.6.orig/mm/memory.c
+++ linux-2.6/mm/memory.c
@@ -1288,6 +1288,11 @@ EXPORT_SYMBOL(vm_insert_page);
*
* This function should only be called from a vm_ops->fault handler, and
* in that case the handler should return NULL.
+ *
+ * vma cannot be a COW mapping.
+ *
+ * As this is called only for pages that do not currently exist, we
+ * do not need to flush old virtual caches or the TLB.
*/
int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr, unsigned
long pfn)
{
@@ -2346,54 +2351,6 @@ static int do_nonlinear_fault(struct mm_
}
/*
- * do_no_pfn() tries to create a new page mapping for a page without
- * a struct_page backing it
- *
- * As this is called only for pages that do not currently exist, we
- * do not need to flush old virtual caches or the TLB.
- *
- * We enter with non-exclusive mmap_sem (to exclude vma changes,
- * but allow concurrent faults), and pte mapped but not yet locked.
- * We return with mmap_sem still held, but pte unmapped and unlocked.
- *
- * It is expected that the ->nopfn handler always returns the same pfn
- * for a given virtual mapping.
- *
- * Mark this `noinline' to prevent it from bloating the main pagefault code.
- */
-static noinline int do_no_pfn(struct mm_struct *mm, struct vm_area_struct *vma,
-unsigned long address, pte_t *page_table, pmd_t *pmd,
-int write_access)
-{
- spinlock_t *ptl;
- pte_t entry;
- unsigned long pfn;
- int ret = VM_FAULT_MINOR;
-
- pte_unmap(page_table);
- BUG_ON(!(vma->vm_flags & VM_PFNMAP));
- BUG_ON(is_cow_mapping(vma->vm_flags));
-
- pfn = vma->vm_ops->nopfn(vma, address & PAGE_MASK);
- if
[patch 6/7] mm: merge nopfn into fault
Remove -nopfn and reimplement the only existing handler using -fault
Signed-off-by: Nick Piggin [EMAIL PROTECTED]
Index: linux-2.6/drivers/char/mspec.c
===
--- linux-2.6.orig/drivers/char/mspec.c
+++ linux-2.6/drivers/char/mspec.c
@@ -182,24 +182,25 @@ mspec_close(struct vm_area_struct *vma)
/*
- * mspec_nopfn
+ * mspec_fault
*
* Creates a mspec page and maps it to user space.
*/
-static unsigned long
-mspec_nopfn(struct vm_area_struct *vma, unsigned long address)
+static struct page *
+mspec_fault(struct fault_data *fdata)
{
unsigned long paddr, maddr;
unsigned long pfn;
- int index;
- struct vma_data *vdata = vma-vm_private_data;
+ int index = fdata-pgoff;
+ struct vma_data *vdata = fdata-vma-vm_private_data;
- index = (address - vma-vm_start) PAGE_SHIFT;
maddr = (volatile unsigned long) vdata-maddr[index];
if (maddr == 0) {
maddr = uncached_alloc_page(numa_node_id());
- if (maddr == 0)
- return NOPFN_OOM;
+ if (maddr == 0) {
+ fdata-type = VM_FAULT_OOM;
+ return NULL;
+ }
spin_lock(vdata-lock);
if (vdata-maddr[index] == 0) {
@@ -219,13 +220,21 @@ mspec_nopfn(struct vm_area_struct *vma,
pfn = paddr PAGE_SHIFT;
- return pfn;
+ fdata-type = VM_FAULT_MINOR;
+ /*
+* vm_insert_pfn can fail with -EBUSY, but in that case it will
+* be because another thread has installed the pte first, so it
+* is no problem.
+*/
+ vm_insert_pfn(fdata-vma, fdata-address, pfn);
+
+ return NULL;
}
static struct vm_operations_struct mspec_vm_ops = {
.open = mspec_open,
.close = mspec_close,
- .nopfn = mspec_nopfn
+ .fault = mspec_fault,
};
/*
Index: linux-2.6/include/linux/mm.h
===
--- linux-2.6.orig/include/linux/mm.h
+++ linux-2.6/include/linux/mm.h
@@ -228,7 +228,6 @@ struct vm_operations_struct {
void (*close)(struct vm_area_struct * area);
struct page * (*fault)(struct vm_area_struct *vma, struct fault_data *
fdata);
struct page * (*nopage)(struct vm_area_struct * area, unsigned long
address, int *type);
- unsigned long (*nopfn)(struct vm_area_struct * area, unsigned long
address);
int (*populate)(struct vm_area_struct * area, unsigned long address,
unsigned long len, pgprot_t prot, unsigned long pgoff, int nonblock);
/* notification that a previously read-only page is about to become
@@ -659,12 +658,6 @@ static inline int page_mapped(struct pag
#define NOPAGE_OOM ((struct page *) (-1))
/*
- * Error return values for the *_nopfn functions
- */
-#define NOPFN_SIGBUS ((unsigned long) -1)
-#define NOPFN_OOM ((unsigned long) -2)
-
-/*
* Different kinds of faults, as returned by handle_mm_fault().
* Used to decide whether a process gets delivered SIGBUS or
* just gets major/minor fault counters bumped up.
Index: linux-2.6/mm/memory.c
===
--- linux-2.6.orig/mm/memory.c
+++ linux-2.6/mm/memory.c
@@ -1288,6 +1288,11 @@ EXPORT_SYMBOL(vm_insert_page);
*
* This function should only be called from a vm_ops-fault handler, and
* in that case the handler should return NULL.
+ *
+ * vma cannot be a COW mapping.
+ *
+ * As this is called only for pages that do not currently exist, we
+ * do not need to flush old virtual caches or the TLB.
*/
int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr, unsigned
long pfn)
{
@@ -2346,54 +2351,6 @@ static int do_nonlinear_fault(struct mm_
}
/*
- * do_no_pfn() tries to create a new page mapping for a page without
- * a struct_page backing it
- *
- * As this is called only for pages that do not currently exist, we
- * do not need to flush old virtual caches or the TLB.
- *
- * We enter with non-exclusive mmap_sem (to exclude vma changes,
- * but allow concurrent faults), and pte mapped but not yet locked.
- * We return with mmap_sem still held, but pte unmapped and unlocked.
- *
- * It is expected that the -nopfn handler always returns the same pfn
- * for a given virtual mapping.
- *
- * Mark this `noinline' to prevent it from bloating the main pagefault code.
- */
-static noinline int do_no_pfn(struct mm_struct *mm, struct vm_area_struct *vma,
-unsigned long address, pte_t *page_table, pmd_t *pmd,
-int write_access)
-{
- spinlock_t *ptl;
- pte_t entry;
- unsigned long pfn;
- int ret = VM_FAULT_MINOR;
-
- pte_unmap(page_table);
- BUG_ON(!(vma-vm_flags VM_PFNMAP));
- BUG_ON(is_cow_mapping(vma-vm_flags));
-
- pfn = vma-vm_ops-nopfn(vma, address PAGE_MASK);
- if (pfn == NOPFN_OOM)
-
