[PATCH v4 6/7] mm, dax: make pmd_fault() and friends to be the same as fault()

From: Ross Zwisler
Date: Tue Jan 10 2017 - 16:52:58 EST

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From: Dave Jiang <dave.jiang@xxxxxxxxx>

Instead of passing in multiple parameters in the pmd_fault() handler,
a vmf can be passed in just like a fault() handler. This will simplify
code and remove the need for the actual pmd fault handlers to allocate a
vmf. Related functions are also modified to do the same.

Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Reviewed-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
---
drivers/dax/dax.c | 16 +++++++---------
fs/dax.c | 42 ++++++++++++++++++------------------------
fs/ext4/file.c | 9 ++++-----
fs/xfs/xfs_file.c | 10 ++++------
include/linux/dax.h | 7 +++----
include/linux/mm.h | 3 +--
include/trace/events/fs_dax.h | 15 +++++++--------
mm/memory.c | 6 ++----
8 files changed, 46 insertions(+), 62 deletions(-)

diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
index ed758b7..a8833cc 100644
--- a/drivers/dax/dax.c
+++ b/drivers/dax/dax.c
@@ -473,10 +473,9 @@ static int dax_dev_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
}

static int __dax_dev_pmd_fault(struct dax_dev *dax_dev,
- struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd,
- unsigned int flags)
+ struct vm_area_struct *vma, struct vm_fault *vmf)
{
- unsigned long pmd_addr = addr & PMD_MASK;
+ unsigned long pmd_addr = vmf->address & PMD_MASK;
struct device *dev = &dax_dev->dev;
struct dax_region *dax_region;
phys_addr_t phys;
@@ -508,23 +507,22 @@ static int __dax_dev_pmd_fault(struct dax_dev *dax_dev,

pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);

- return vmf_insert_pfn_pmd(vma, addr, pmd, pfn,
- flags & FAULT_FLAG_WRITE);
+ return vmf_insert_pfn_pmd(vma, vmf->address, vmf->pmd, pfn,
+ vmf->flags & FAULT_FLAG_WRITE);
}

-static int dax_dev_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
- pmd_t *pmd, unsigned int flags)
+static int dax_dev_pmd_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
int rc;
struct file *filp = vma->vm_file;
struct dax_dev *dax_dev = filp->private_data;

dev_dbg(&dax_dev->dev, "%s: %s: %s (%#lx - %#lx)\n", __func__,
- current->comm, (flags & FAULT_FLAG_WRITE)
+ current->comm, (vmf->flags & FAULT_FLAG_WRITE)
? "write" : "read", vma->vm_start, vma->vm_end);

rcu_read_lock();
- rc = __dax_dev_pmd_fault(dax_dev, vma, addr, pmd, flags);
+ rc = __dax_dev_pmd_fault(dax_dev, vma, vmf);
rcu_read_unlock();

return rc;
diff --git a/fs/dax.c b/fs/dax.c
index 4671530..2ef7847 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1332,18 +1332,17 @@ static int dax_pmd_load_hole(struct vm_area_struct *vma, pmd_t *pmd,
return VM_FAULT_FALLBACK;
}

-int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
- pmd_t *pmd, unsigned int flags, struct iomap_ops *ops)
+int dax_iomap_pmd_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
+ struct iomap_ops *ops)
{
struct address_space *mapping = vma->vm_file->f_mapping;
- unsigned long pmd_addr = address & PMD_MASK;
- bool write = flags & FAULT_FLAG_WRITE;
+ unsigned long pmd_addr = vmf->address & PMD_MASK;
+ bool write = vmf->flags & FAULT_FLAG_WRITE;
unsigned int iomap_flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT;
struct inode *inode = mapping->host;
int result = VM_FAULT_FALLBACK;
struct iomap iomap = { 0 };
- pgoff_t max_pgoff, pgoff;
- struct vm_fault vmf;
+ pgoff_t max_pgoff;
void *entry;
loff_t pos;
int error;
@@ -1353,10 +1352,10 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
* supposed to hold locks serializing us with truncate / punch hole so
* this is a reliable test.
*/
- pgoff = linear_page_index(vma, pmd_addr);
+ vmf->pgoff = linear_page_index(vma, pmd_addr);
max_pgoff = (i_size_read(inode) - 1) >> PAGE_SHIFT;

- trace_dax_pmd_fault(inode, vma, address, flags, pgoff, max_pgoff, 0);
+ trace_dax_pmd_fault(inode, vma, vmf, max_pgoff, 0);

/* Fall back to PTEs if we're going to COW */
if (write && !(vma->vm_flags & VM_SHARED))
@@ -1368,13 +1367,13 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
if ((pmd_addr + PMD_SIZE) > vma->vm_end)
goto fallback;

- if (pgoff > max_pgoff) {
+ if (vmf->pgoff > max_pgoff) {
result = VM_FAULT_SIGBUS;
goto out;
}

/* If the PMD would extend beyond the file size */
- if ((pgoff | PG_PMD_COLOUR) > max_pgoff)
+ if ((vmf->pgoff | PG_PMD_COLOUR) > max_pgoff)
goto fallback;

/*
@@ -1382,7 +1381,7 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
* setting up a mapping, so really we're using iomap_begin() as a way
* to look up our filesystem block.
*/
- pos = (loff_t)pgoff << PAGE_SHIFT;
+ pos = (loff_t)vmf->pgoff << PAGE_SHIFT;
error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap);
if (error)
goto fallback;
@@ -1396,25 +1395,21 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
* the tree, for instance), it will return -EEXIST and we just fall
* back to 4k entries.
*/
- entry = grab_mapping_entry(mapping, pgoff, RADIX_DAX_PMD);
+ entry = grab_mapping_entry(mapping, vmf->pgoff, RADIX_DAX_PMD);
if (IS_ERR(entry))
goto finish_iomap;

- vmf.pgoff = pgoff;
- vmf.flags = flags;
- vmf.gfp_mask = mapping_gfp_mask(mapping) | __GFP_IO;
-
switch (iomap.type) {
case IOMAP_MAPPED:
- result = dax_pmd_insert_mapping(vma, pmd, &vmf, address,
- &iomap, pos, write, &entry);
+ result = dax_pmd_insert_mapping(vma, vmf->pmd, vmf,
+ vmf->address, &iomap, pos, write, &entry);
break;
case IOMAP_UNWRITTEN:
case IOMAP_HOLE:
if (WARN_ON_ONCE(write))
goto unlock_entry;
- result = dax_pmd_load_hole(vma, pmd, &vmf, address, &iomap,
- &entry);
+ result = dax_pmd_load_hole(vma, vmf->pmd, vmf, vmf->address,
+ &iomap, &entry);
break;
default:
WARN_ON_ONCE(1);
@@ -1422,7 +1417,7 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
}

unlock_entry:
- put_locked_mapping_entry(mapping, pgoff, entry);
+ put_locked_mapping_entry(mapping, vmf->pgoff, entry);
finish_iomap:
if (ops->iomap_end) {
int copied = PMD_SIZE;
@@ -1440,12 +1435,11 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
}
fallback:
if (result == VM_FAULT_FALLBACK) {
- split_huge_pmd(vma, pmd, address);
+ split_huge_pmd(vma, vmf->pmd, vmf->address);
count_vm_event(THP_FAULT_FALLBACK);
}
out:
- trace_dax_pmd_fault_done(inode, vma, address, flags, pgoff, max_pgoff,
- result);
+ trace_dax_pmd_fault_done(inode, vma, vmf, max_pgoff, result);
return result;
}
EXPORT_SYMBOL_GPL(dax_iomap_pmd_fault);
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index d663d3d..10b64ba 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -275,21 +275,20 @@ static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
return result;
}

-static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
- pmd_t *pmd, unsigned int flags)
+static int
+ext4_dax_pmd_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
int result;
struct inode *inode = file_inode(vma->vm_file);
struct super_block *sb = inode->i_sb;
- bool write = flags & FAULT_FLAG_WRITE;
+ bool write = vmf->flags & FAULT_FLAG_WRITE;

if (write) {
sb_start_pagefault(sb);
file_update_time(vma->vm_file);
}
down_read(&EXT4_I(inode)->i_mmap_sem);
- result = dax_iomap_pmd_fault(vma, addr, pmd, flags,
- &ext4_iomap_ops);
+ result = dax_iomap_pmd_fault(vma, vmf, &ext4_iomap_ops);
up_read(&EXT4_I(inode)->i_mmap_sem);
if (write)
sb_end_pagefault(sb);
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 0f77519..332e194 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1432,9 +1432,7 @@ xfs_filemap_fault(
STATIC int
xfs_filemap_pmd_fault(
struct vm_area_struct *vma,
- unsigned long addr,
- pmd_t *pmd,
- unsigned int flags)
+ struct vm_fault *vmf)
{
struct inode *inode = file_inode(vma->vm_file);
struct xfs_inode *ip = XFS_I(inode);
@@ -1445,16 +1443,16 @@ xfs_filemap_pmd_fault(

trace_xfs_filemap_pmd_fault(ip);

- if (flags & FAULT_FLAG_WRITE) {
+ if (vmf->flags & FAULT_FLAG_WRITE) {
sb_start_pagefault(inode->i_sb);
file_update_time(vma->vm_file);
}

xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
- ret = dax_iomap_pmd_fault(vma, addr, pmd, flags, &xfs_iomap_ops);
+ ret = dax_iomap_pmd_fault(vma, vmf, &xfs_iomap_ops);
xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);

- if (flags & FAULT_FLAG_WRITE)
+ if (vmf->flags & FAULT_FLAG_WRITE)
sb_end_pagefault(inode->i_sb);

return ret;
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 24ad711..a829fee 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -71,16 +71,15 @@ static inline unsigned int dax_radix_order(void *entry)
return PMD_SHIFT - PAGE_SHIFT;
return 0;
}
-int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
- pmd_t *pmd, unsigned int flags, struct iomap_ops *ops);
+int dax_iomap_pmd_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
+ struct iomap_ops *ops);
#else
static inline unsigned int dax_radix_order(void *entry)
{
return 0;
}
static inline int dax_iomap_pmd_fault(struct vm_area_struct *vma,
- unsigned long address, pmd_t *pmd, unsigned int flags,
- struct iomap_ops *ops)
+ struct vm_fault *vmf, struct iomap_ops *ops)
{
return VM_FAULT_FALLBACK;
}
diff --git a/include/linux/mm.h b/include/linux/mm.h
index aaf4c96..1c96128 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -347,8 +347,7 @@ struct vm_operations_struct {
void (*close)(struct vm_area_struct * area);
int (*mremap)(struct vm_area_struct * area);
int (*fault)(struct vm_area_struct *vma, struct vm_fault *vmf);
- int (*pmd_fault)(struct vm_area_struct *, unsigned long address,
- pmd_t *, unsigned int flags);
+ int (*pmd_fault)(struct vm_area_struct *vma, struct vm_fault *vmf);
void (*map_pages)(struct vm_fault *vmf,
pgoff_t start_pgoff, pgoff_t end_pgoff);

diff --git a/include/trace/events/fs_dax.h b/include/trace/events/fs_dax.h
index c3b0aae..a98665b 100644
--- a/include/trace/events/fs_dax.h
+++ b/include/trace/events/fs_dax.h
@@ -8,9 +8,8 @@

DECLARE_EVENT_CLASS(dax_pmd_fault_class,
TP_PROTO(struct inode *inode, struct vm_area_struct *vma,
- unsigned long address, unsigned int flags, pgoff_t pgoff,
- pgoff_t max_pgoff, int result),
- TP_ARGS(inode, vma, address, flags, pgoff, max_pgoff, result),
+ struct vm_fault *vmf, pgoff_t max_pgoff, int result),
+ TP_ARGS(inode, vma, vmf, max_pgoff, result),
TP_STRUCT__entry(
__field(unsigned long, ino)
__field(unsigned long, vm_start)
@@ -29,9 +28,9 @@ DECLARE_EVENT_CLASS(dax_pmd_fault_class,
__entry->vm_start = vma->vm_start;
__entry->vm_end = vma->vm_end;
__entry->vm_flags = vma->vm_flags;
- __entry->address = address;
- __entry->flags = flags;
- __entry->pgoff = pgoff;
+ __entry->address = vmf->address;
+ __entry->flags = vmf->flags;
+ __entry->pgoff = vmf->pgoff;
__entry->max_pgoff = max_pgoff;
__entry->result = result;
),
@@ -54,9 +53,9 @@ DECLARE_EVENT_CLASS(dax_pmd_fault_class,
#define DEFINE_PMD_FAULT_EVENT(name) \
DEFINE_EVENT(dax_pmd_fault_class, name, \
TP_PROTO(struct inode *inode, struct vm_area_struct *vma, \
- unsigned long address, unsigned int flags, pgoff_t pgoff, \
+ struct vm_fault *vmf, \
pgoff_t max_pgoff, int result), \
- TP_ARGS(inode, vma, address, flags, pgoff, max_pgoff, result))
+ TP_ARGS(inode, vma, vmf, max_pgoff, result))

DEFINE_PMD_FAULT_EVENT(dax_pmd_fault);
DEFINE_PMD_FAULT_EVENT(dax_pmd_fault_done);
diff --git a/mm/memory.c b/mm/memory.c
index 03691d6..e648c62 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3475,8 +3475,7 @@ static int create_huge_pmd(struct vm_fault *vmf)
if (vma_is_anonymous(vma))
return do_huge_pmd_anonymous_page(vmf);
if (vma->vm_ops->pmd_fault)
- return vma->vm_ops->pmd_fault(vma, vmf->address, vmf->pmd,
- vmf->flags);
+ return vma->vm_ops->pmd_fault(vma, vmf);
return VM_FAULT_FALLBACK;
}

@@ -3485,8 +3484,7 @@ static int wp_huge_pmd(struct vm_fault *vmf, pmd_t orig_pmd)
if (vma_is_anonymous(vmf->vma))
return do_huge_pmd_wp_page(vmf, orig_pmd);
if (vmf->vma->vm_ops->pmd_fault)
- return vmf->vma->vm_ops->pmd_fault(vmf->vma, vmf->address,
- vmf->pmd, vmf->flags);
+ return vmf->vma->vm_ops->pmd_fault(vmf->vma, vmf);

/* COW handled on pte level: split pmd */
VM_BUG_ON_VMA(vmf->vma->vm_flags & VM_SHARED, vmf->vma);
--
2.7.4

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