[PATCH 3/7] mm: kill vma flag VM_CAN_NONLINEAR

From: Konstantin Khlebnikov
Date: Sat Mar 31 2012 - 05:30:06 EST

This patch moves actual ptes filling for non-linear file mappings
into special vma operation: ->remap_pages().

Now fs must implement this method to get non-linear mappings support.
If fs uses filemap_fault() then it can use generic_file_remap_pages() for this.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Nick Piggin <npiggin@xxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
---
drivers/staging/android/ashmem.c | 1 -
fs/9p/vfs_file.c | 1 +
fs/btrfs/file.c | 2 +-
fs/ceph/addr.c | 2 +-
fs/cifs/file.c | 1 +
fs/ecryptfs/file.c | 1 +
fs/ext4/file.c | 2 +-
fs/fuse/file.c | 1 +
fs/gfs2/file.c | 2 +-
fs/nfs/file.c | 1 +
fs/nilfs2/file.c | 2 +-
fs/ocfs2/mmap.c | 2 +-
fs/ubifs/file.c | 1 +
fs/xfs/xfs_file.c | 2 +-
include/linux/fs.h | 2 ++
include/linux/mm.h | 6 +++---
mm/filemap.c | 2 +-
mm/filemap_xip.c | 3 ++-
mm/fremap.c | 14 ++++++++------
mm/mmap.c | 3 +--
mm/nommu.c | 8 ++++++++
mm/shmem.c | 3 +--
22 files changed, 39 insertions(+), 23 deletions(-)

diff --git a/drivers/staging/android/ashmem.c b/drivers/staging/android/ashmem.c
index 9f1f27e..8b36d3d 100644
--- a/drivers/staging/android/ashmem.c
+++ b/drivers/staging/android/ashmem.c
@@ -329,7 +329,6 @@ static int ashmem_mmap(struct file *file, struct vm_area_struct *vma)
if (vma->vm_file)
fput(vma->vm_file);
vma->vm_file = asma->file;
- vma->vm_flags |= VM_CAN_NONLINEAR;

out:
mutex_unlock(&ashmem_mutex);
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index fc06fd2..34b84f0 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -735,6 +735,7 @@ v9fs_cached_file_write(struct file *filp, const char __user * data,
static const struct vm_operations_struct v9fs_file_vm_ops = {
.fault = filemap_fault,
.page_mkwrite = v9fs_vm_page_mkwrite,
+ .remap_pages = generic_file_remap_pages,
};


diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index d83260d..29a8cfb 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1576,6 +1576,7 @@ out:
static const struct vm_operations_struct btrfs_file_vm_ops = {
.fault = filemap_fault,
.page_mkwrite = btrfs_page_mkwrite,
+ .remap_pages = generic_file_remap_pages,
};

static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
@@ -1587,7 +1588,6 @@ static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)

file_accessed(filp);
vma->vm_ops = &btrfs_file_vm_ops;
- vma->vm_flags |= VM_CAN_NONLINEAR;

return 0;
}
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 173b1d2..1745051 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1219,6 +1219,7 @@ out:
static struct vm_operations_struct ceph_vmops = {
.fault = filemap_fault,
.page_mkwrite = ceph_page_mkwrite,
+ .remap_pages = generic_file_remap_pages,
};

int ceph_mmap(struct file *file, struct vm_area_struct *vma)
@@ -1229,6 +1230,5 @@ int ceph_mmap(struct file *file, struct vm_area_struct *vma)
return -ENOEXEC;
file_accessed(file);
vma->vm_ops = &ceph_vmops;
- vma->vm_flags |= VM_CAN_NONLINEAR;
return 0;
}
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 460d87b..591757f 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2557,6 +2557,7 @@ cifs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
static struct vm_operations_struct cifs_file_vm_ops = {
.fault = filemap_fault,
.page_mkwrite = cifs_page_mkwrite,
+ .remap_pages = generic_file_remap_pages,
};

int cifs_file_strict_mmap(struct file *file, struct vm_area_struct *vma)
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 2b17f2f..367de3b 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -146,6 +146,7 @@ static void ecryptfs_vma_close(struct vm_area_struct *vma)
static const struct vm_operations_struct ecryptfs_file_vm_ops = {
.close = ecryptfs_vma_close,
.fault = filemap_fault,
+ .remap_pages = generic_file_remap_pages,
};

static int ecryptfs_file_mmap(struct file *file, struct vm_area_struct *vma)
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index cb70f18..adc9a39 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -144,6 +144,7 @@ ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
static const struct vm_operations_struct ext4_file_vm_ops = {
.fault = filemap_fault,
.page_mkwrite = ext4_page_mkwrite,
+ .remap_pages = generic_file_remap_pages,
};

static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
@@ -154,7 +155,6 @@ static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
return -ENOEXEC;
file_accessed(file);
vma->vm_ops = &ext4_file_vm_ops;
- vma->vm_flags |= VM_CAN_NONLINEAR;
return 0;
}

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index a841868..804f0ac 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1331,6 +1331,7 @@ static const struct vm_operations_struct fuse_file_vm_ops = {
.close = fuse_vma_close,
.fault = filemap_fault,
.page_mkwrite = fuse_page_mkwrite,
+ .remap_pages = generic_file_remap_pages,
};

static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 7683458..9f0804b 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -470,6 +470,7 @@ out:
static const struct vm_operations_struct gfs2_vm_ops = {
.fault = filemap_fault,
.page_mkwrite = gfs2_page_mkwrite,
+ .remap_pages = generic_file_remap_pages,
};

/**
@@ -504,7 +505,6 @@ static int gfs2_mmap(struct file *file, struct vm_area_struct *vma)
return error;
}
vma->vm_ops = &gfs2_vm_ops;
- vma->vm_flags |= VM_CAN_NONLINEAR;

return 0;
}
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index aa9b709..31eae53 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -550,6 +550,7 @@ out:
static const struct vm_operations_struct nfs_file_vm_ops = {
.fault = filemap_fault,
.page_mkwrite = nfs_vm_page_mkwrite,
+ .remap_pages = generic_file_remap_pages,
};

static int nfs_need_sync_write(struct file *filp, struct inode *inode)
diff --git a/fs/nilfs2/file.c b/fs/nilfs2/file.c
index 2660152..303cbb9 100644
--- a/fs/nilfs2/file.c
+++ b/fs/nilfs2/file.c
@@ -126,13 +126,13 @@ static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
static const struct vm_operations_struct nilfs_file_vm_ops = {
.fault = filemap_fault,
.page_mkwrite = nilfs_page_mkwrite,
+ .remap_pages = generic_file_remap_pages,
};

static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
{
file_accessed(file);
vma->vm_ops = &nilfs_file_vm_ops;
- vma->vm_flags |= VM_CAN_NONLINEAR;
return 0;
}

diff --git a/fs/ocfs2/mmap.c b/fs/ocfs2/mmap.c
index 9cd4108..7aef3f4 100644
--- a/fs/ocfs2/mmap.c
+++ b/fs/ocfs2/mmap.c
@@ -171,6 +171,7 @@ out:
static const struct vm_operations_struct ocfs2_file_vm_ops = {
.fault = ocfs2_fault,
.page_mkwrite = ocfs2_page_mkwrite,
+ .remap_pages = generic_file_remap_pages,
};

int ocfs2_mmap(struct file *file, struct vm_area_struct *vma)
@@ -186,7 +187,6 @@ int ocfs2_mmap(struct file *file, struct vm_area_struct *vma)
ocfs2_inode_unlock(file->f_dentry->d_inode, lock_level);
out:
vma->vm_ops = &ocfs2_file_vm_ops;
- vma->vm_flags |= VM_CAN_NONLINEAR;
return 0;
}

diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 5c8f6dc..fc59462 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1536,6 +1536,7 @@ out_unlock:
static const struct vm_operations_struct ubifs_file_vm_ops = {
.fault = filemap_fault,
.page_mkwrite = ubifs_vm_page_mkwrite,
+ .remap_pages = generic_file_remap_pages,
};

static int ubifs_file_mmap(struct file *file, struct vm_area_struct *vma)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 54a67dd..4381874 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -987,7 +987,6 @@ xfs_file_mmap(
struct vm_area_struct *vma)
{
vma->vm_ops = &xfs_file_vm_ops;
- vma->vm_flags |= VM_CAN_NONLINEAR;

file_accessed(filp);
return 0;
@@ -1041,4 +1040,5 @@ const struct file_operations xfs_dir_file_operations = {
static const struct vm_operations_struct xfs_file_vm_ops = {
.fault = filemap_fault,
.page_mkwrite = xfs_vm_page_mkwrite,
+ .remap_pages = generic_file_remap_pages,
};
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 135693e..db55afd 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2356,6 +2356,8 @@ extern int sb_min_blocksize(struct super_block *, int);

extern int generic_file_mmap(struct file *, struct vm_area_struct *);
extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
+extern int generic_file_remap_pages(struct vm_area_struct *, unsigned long addr,
+ unsigned long size, pgoff_t pgoff);
extern int file_read_actor(read_descriptor_t * desc, struct page *page, unsigned long offset, unsigned long size);
int generic_write_checks(struct file *file, loff_t *pos, size_t *count, int isblk);
extern ssize_t generic_file_aio_read(struct kiocb *, const struct iovec *, unsigned long, loff_t);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index a444f47..0dad037 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -106,7 +106,6 @@ extern unsigned int kobjsize(const void *objp);
#define VM_INSERTPAGE 0x02000000 /* The vma has had "vm_insert_page()" done on it */
#define VM_NODUMP 0x04000000 /* Do not include in the core dump */

-#define VM_CAN_NONLINEAR 0x08000000 /* Has ->fault & does nonlinear pages */
#define VM_MIXEDMAP 0x10000000 /* Can contain "struct page" and pure PFN pages */
#define VM_HUGEPAGE 0x20000000 /* MADV_HUGEPAGE marked this vma */
#define VM_NOHUGEPAGE 0x40000000 /* MADV_NOHUGEPAGE marked this vma */
@@ -177,8 +176,7 @@ static inline int is_pfn_mapping(struct vm_area_struct *vma)
* of VM_FAULT_xxx flags that give details about how the fault was handled.
*
* pgoff should be used in favour of virtual_address, if possible. If pgoff
- * is used, one may set VM_CAN_NONLINEAR in the vma->vm_flags to get nonlinear
- * mapping support.
+ * is used, one may implement ->remap_pages to get nonlinear mapping support.
*/
struct vm_fault {
unsigned int flags; /* FAULT_FLAG_xxx flags */
@@ -236,6 +234,8 @@ struct vm_operations_struct {
int (*migrate)(struct vm_area_struct *vma, const nodemask_t *from,
const nodemask_t *to, unsigned long flags);
#endif
+ int (*remap_pages)(struct vm_area_struct *vma, unsigned long addr,
+ unsigned long size, pgoff_t pgoff);
};

struct mmu_gather;
diff --git a/mm/filemap.c b/mm/filemap.c
index 79c4b2b..34cce46 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1753,6 +1753,7 @@ EXPORT_SYMBOL(filemap_fault);

const struct vm_operations_struct generic_file_vm_ops = {
.fault = filemap_fault,
+ .remap_pages = generic_file_remap_pages,
};

/* This is used for a general mmap of a disk file */
@@ -1765,7 +1766,6 @@ int generic_file_mmap(struct file * file, struct vm_area_struct * vma)
return -ENOEXEC;
file_accessed(file);
vma->vm_ops = &generic_file_vm_ops;
- vma->vm_flags |= VM_CAN_NONLINEAR;
return 0;
}

diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index a4eb311..3c38d07 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -304,6 +304,7 @@ out:

static const struct vm_operations_struct xip_file_vm_ops = {
.fault = xip_file_fault,
+ .remap_pages = generic_file_remap_pages,
};

int xip_file_mmap(struct file * file, struct vm_area_struct * vma)
@@ -312,7 +313,7 @@ int xip_file_mmap(struct file * file, struct vm_area_struct * vma)

file_accessed(file);
vma->vm_ops = &xip_file_vm_ops;
- vma->vm_flags |= VM_CAN_NONLINEAR | VM_MIXEDMAP;
+ vma->vm_flags |= VM_MIXEDMAP;
return 0;
}
EXPORT_SYMBOL_GPL(xip_file_mmap);
diff --git a/mm/fremap.c b/mm/fremap.c
index 9ed4fd4..c70190a 100644
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -5,6 +5,7 @@
*
* started by Ingo Molnar, Copyright (C) 2002, 2003
*/
+#include <linux/export.h>
#include <linux/backing-dev.h>
#include <linux/mm.h>
#include <linux/swap.h>
@@ -80,9 +81,10 @@ out:
return err;
}

-static int populate_range(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long addr, unsigned long size, pgoff_t pgoff)
+int generic_file_remap_pages(struct vm_area_struct *vma, unsigned long addr,
+ unsigned long size, pgoff_t pgoff)
{
+ struct mm_struct *mm = vma->vm_mm;
int err;

do {
@@ -95,9 +97,9 @@ static int populate_range(struct mm_struct *mm, struct vm_area_struct *vma,
pgoff++;
} while (size);

- return 0;
-
+ return 0;
}
+EXPORT_SYMBOL(generic_file_remap_pages);

/**
* sys_remap_file_pages - remap arbitrary pages of an existing VM_SHARED vma
@@ -167,7 +169,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
if (vma->vm_private_data && !(vma->vm_flags & VM_NONLINEAR))
goto out;

- if (!(vma->vm_flags & VM_CAN_NONLINEAR))
+ if (!vma->vm_ops->remap_pages)
goto out;

if (start < vma->vm_start || start + size > vma->vm_end)
@@ -229,7 +231,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
}

mmu_notifier_invalidate_range_start(mm, start, start + size);
- err = populate_range(mm, vma, start, size, pgoff);
+ err = vma->vm_ops->remap_pages(vma, start, size, pgoff);
mmu_notifier_invalidate_range_end(mm, start, start + size);
if (!err && !(flags & MAP_NONBLOCK)) {
if (vma->vm_flags & VM_LOCKED) {
diff --git a/mm/mmap.c b/mm/mmap.c
index a7bf6a3..1a23d2c 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -649,8 +649,7 @@ again: remove_next = 1 + (end > next->vm_end);
static inline int is_mergeable_vma(struct vm_area_struct *vma,
struct file *file, unsigned long vm_flags)
{
- /* VM_CAN_NONLINEAR may get set later by f_op->mmap() */
- if ((vma->vm_flags ^ vm_flags) & ~VM_CAN_NONLINEAR)
+ if (vma->vm_flags ^ vm_flags)
return 0;
if (vma->vm_file != file)
return 0;
diff --git a/mm/nommu.c b/mm/nommu.c
index f59e170..afa0a15 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1961,6 +1961,14 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
}
EXPORT_SYMBOL(filemap_fault);

+int generic_file_remap_pages(struct vm_area_struct *vma, unsigned long addr,
+ unsigned long size, pgoff_t pgoff)
+{
+ BUG();
+ return 0;
+}
+EXPORT_SYMBOL(generic_file_remap_pages);
+
static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
unsigned long addr, void *buf, int len, int write)
{
diff --git a/mm/shmem.c b/mm/shmem.c
index f99ff3e..617621a 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1112,7 +1112,6 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
{
file_accessed(file);
vma->vm_ops = &shmem_vm_ops;
- vma->vm_flags |= VM_CAN_NONLINEAR;
return 0;
}

@@ -2430,6 +2429,7 @@ static const struct vm_operations_struct shmem_vm_ops = {
.set_policy = shmem_set_policy,
.get_policy = shmem_get_policy,
#endif
+ .remap_pages = generic_file_remap_pages,
};

static struct dentry *shmem_mount(struct file_system_type *fs_type,
@@ -2623,7 +2623,6 @@ int shmem_zero_setup(struct vm_area_struct *vma)
fput(vma->vm_file);
vma->vm_file = file;
vma->vm_ops = &shmem_vm_ops;
- vma->vm_flags |= VM_CAN_NONLINEAR;
return 0;
}


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