Instead of calling aops->get_xip_mem from the fault handler, allow the
filesystem to pass in a get_block_t that is used to find the appropriate
blocks.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@xxxxxxxxx>
---
fs/ext2/file.c | 25 ++++++++++++--
fs/xip.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/fs.h | 13 ++++---
mm/filemap_xip.c | 92 --------------------------------------------------
4 files changed, 130 insertions(+), 99 deletions(-)
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index b0eb1d4..47a0b1d 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -25,6 +25,27 @@
#include "xattr.h"
#include "acl.h"
+static int ext2_xip_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ return xip_fault(vma, vmf, ext2_get_block);
+}
+
+static const struct vm_operations_struct ext2_xip_vm_ops = {
+ .fault = ext2_xip_fault,
+ .remap_pages = generic_file_remap_pages,
+};
+
+static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ if (!IS_XIP(file_inode(file)))
+ return generic_file_mmap(file, vma);
+
+ file_accessed(file);
+ vma->vm_ops = &ext2_xip_vm_ops;
+ vma->vm_flags |= VM_MIXEDMAP;
+ return 0;
+}
+
/*
* Called when filp is released. This happens when all file descriptors
* for a single struct file are closed. Note that different open() calls
@@ -70,7 +91,7 @@ const struct file_operations ext2_file_operations = {
#ifdef CONFIG_COMPAT
.compat_ioctl = ext2_compat_ioctl,
#endif
- .mmap = generic_file_mmap,
+ .mmap = ext2_file_mmap,
.open = dquot_file_open,
.release = ext2_release_file,
.fsync = ext2_fsync,
@@ -89,7 +110,7 @@ const struct file_operations ext2_xip_file_operations = {
#ifdef CONFIG_COMPAT
.compat_ioctl = ext2_compat_ioctl,
#endif
- .mmap = xip_file_mmap,
+ .mmap = ext2_file_mmap,
.open = dquot_file_open,
.release = ext2_release_file,
.fsync = ext2_fsync,
diff --git a/fs/xip.c b/fs/xip.c
index fcb6ffd..5740aed 100644
--- a/fs/xip.c
+++ b/fs/xip.c
@@ -18,6 +18,8 @@
#include <linux/buffer_head.h>
#include <linux/fs.h>
#include <linux/genhd.h>
+#include <linux/highmem.h>
+#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/uio.h>
@@ -31,6 +33,16 @@ static long xip_get_addr(struct inode *inode, struct buffer_head *bh,
return ops->direct_access(bdev, sector, addr, &pfn, bh->b_size);
}
+static long xip_get_pfn(struct inode *inode, struct buffer_head *bh,
+ unsigned long *pfn)
+{
+ struct block_device *bdev = bh->b_bdev;
+ const struct block_device_operations *ops = bdev->bd_disk->fops;
+ void *addr;
+ sector_t sector = bh->b_blocknr << (inode->i_blkbits - 9);
+ return ops->direct_access(bdev, sector, &addr, pfn, bh->b_size);
+}
+
static ssize_t xip_io(int rw, struct inode *inode, const struct iovec *iov,
loff_t start, loff_t end, unsigned nr_segs,
get_block_t get_block, struct buffer_head *bh)
@@ -139,3 +151,90 @@ ssize_t xip_do_io(int rw, struct kiocb *iocb, struct inode *inode,
}
EXPORT_SYMBOL_GPL(xip_do_io);
+static inline void copy_user_bh(struct page *to, struct inode *inode,
+ struct buffer_head *bh, unsigned long vaddr)
+{
+ void *vfrom, *vto;
+ xip_get_addr(inode, bh, &vfrom); /* XXX: error handling */
+ vto = kmap_atomic(to);
+ copy_user_page(vto, vfrom, vaddr, to);
+ kunmap_atomic(vto);
+}
+
+/*
+ * xip_fault() is invoked via the vma operations vector for a
+ * mapped memory region to read in file data during a page fault.
+ *
+ * This function is derived from filemap_fault, but used for execute in place
+ */
+static int do_xip_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
+ get_block_t get_block)
+{
+ struct file *file = vma->vm_file;
+ struct inode *inode = file_inode(file);
+ struct address_space *mapping = file->f_mapping;
+ struct buffer_head bh;
+ unsigned long vaddr = (unsigned long)vmf->virtual_address;
+ sector_t block;
+ pgoff_t size;
+ unsigned long pfn;
+ int error;
+
+ size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ if (vmf->pgoff >= size)
+ return VM_FAULT_SIGBUS;
+
+ memset(&bh, 0, sizeof(bh));
+ block = (sector_t)vmf->pgoff << (PAGE_SHIFT - inode->i_blkbits);
+ bh.b_size = PAGE_SIZE;
+ error = get_block(inode, block, &bh, 0);
+
+ /* Don't allocate backing store if we're going to COW a hole */
+ if (!error && !buffer_mapped(&bh) && !vmf->cow_page) {
+ error = get_block(inode, block, &bh, 1);
+ }
+
+ if (error)
+ return VM_FAULT_SIGBUS;
+
+ /* We must recheck i_size under i_mmap_mutex */
+ mutex_lock(&mapping->i_mmap_mutex);
+ size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ if (unlikely(vmf->pgoff >= size)) {
+ mutex_unlock(&mapping->i_mmap_mutex);
+ return VM_FAULT_SIGBUS;
+ }
+ if (vmf->cow_page) {
+ if (buffer_mapped(&bh))
+ copy_user_bh(vmf->cow_page, inode, &bh, vaddr);
+ else
+ clear_user_highpage(vmf->cow_page, vaddr);
+ return VM_FAULT_COWED;
+ }
+
+ error = xip_get_pfn(inode, &bh, &pfn);
+ if (error > 0)
+ error = vm_insert_mixed(vma, vaddr, pfn);
+ mutex_unlock(&mapping->i_mmap_mutex);
+ if (error == -ENOMEM)
+ return VM_FAULT_OOM;
+ /* -EBUSY is fine, somebody else faulted on the same PTE */
+ if (error != -EBUSY)
+ BUG_ON(error);
+ return VM_FAULT_NOPAGE;
+}
+
+int xip_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
+ get_block_t get_block)
+{
+ int result;
+ struct super_block *sb = file_inode(vma->vm_file)->i_sb;
+
+ sb_start_pagefault(sb);
+ file_update_time(vma->vm_file);
+ result = do_xip_fault(vma, vmf, get_block);
+ sb_end_pagefault(sb);
+
+ return result;
+}
+EXPORT_SYMBOL_GPL(xip_fault);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 26e9095..5c6e175 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -48,6 +48,7 @@ struct cred;
struct swap_info_struct;
struct seq_file;
struct workqueue_struct;
+struct vm_fault;
extern void __init inode_init(void);
extern void __init inode_init_early(void);
@@ -2509,14 +2510,10 @@ extern int generic_file_open(struct inode * inode, struct file * filp);
extern int nonseekable_open(struct inode * inode, struct file * filp);
#ifdef CONFIG_FS_XIP
-extern ssize_t xip_file_read(struct file *filp, char __user *buf, size_t len,
- loff_t *ppos);
-extern int xip_file_mmap(struct file * file, struct vm_area_struct * vma);
-extern ssize_t xip_file_write(struct file *filp, const char __user *buf,
- size_t len, loff_t *ppos);
extern int xip_truncate_page(struct address_space *mapping, loff_t from);
ssize_t xip_do_io(int rw, struct kiocb *, struct inode *, const struct iovec *,
loff_t, unsigned segs, get_block_t, dio_iodone_t, int flags);
+int xip_fault(struct vm_area_struct *, struct vm_fault *, get_block_t);
#else
static inline int xip_truncate_page(struct address_space *mapping, loff_t from)
{
@@ -2528,6 +2525,12 @@ static inline ssize_t xip_do_io(int rw, struct kiocb *iocb, struct inode *inode,
{
return -ENOTTY;
}
+
+static inline int xip_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
+ get_block_t gb)
+{
+ return 0;
+}
#endif
#ifdef CONFIG_BLOCK
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index bea0980..9dd45f3 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -22,98 +22,6 @@
#include <asm/io.h>
/*
- * Only one caller is allowed to try to create mappings at a time.
- * Should move down into filesystem code
- */
-static DEFINE_MUTEX(xip_sparse_mutex);
-
-static inline void copy_user_highdest(struct page *to, void *vfrom,
- unsigned long vaddr)
-{
- char *vto = kmap_atomic(to);
- copy_user_page(vto, vfrom, vaddr, to);
- kunmap_atomic(vto);
-}
-
-/*
- * xip_fault() is invoked via the vma operations vector for a
- * mapped memory region to read in file data during a page fault.
- *
- * This function is derived from filemap_fault, but used for execute in place
- */
-static int xip_file_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
-{
- struct file *file = vma->vm_file;
- struct address_space *mapping = file->f_mapping;
- struct inode *inode = mapping->host;
- unsigned long vaddr = (unsigned long)vmf->virtual_address;
- pgoff_t size;
- void *xip_mem;
- unsigned long xip_pfn;
- int error;
-
- size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
- if (vmf->pgoff >= size)
- return VM_FAULT_SIGBUS;
-
- error = mapping->a_ops->get_xip_mem(mapping, vmf->pgoff, 0,
- &xip_mem, &xip_pfn);
- if (likely(!error))
- goto found;
- /* Don't allocate backing store if we're going to COW a hole */
- if (error == -ENODATA && !vmf->cow_page) {
- mutex_lock(&xip_sparse_mutex);
- error = mapping->a_ops->get_xip_mem(mapping, vmf->pgoff, 1,
- &xip_mem, &xip_pfn);
- mutex_unlock(&xip_sparse_mutex);
- }
- if (error != -ENODATA)
- return VM_FAULT_SIGBUS;
-
-found:
- /* We must recheck i_size under i_mmap_mutex */
- mutex_lock(&mapping->i_mmap_mutex);
- size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
- if (unlikely(vmf->pgoff >= size)) {
- mutex_unlock(&mapping->i_mmap_mutex);
- return VM_FAULT_SIGBUS;
- }
- if (vmf->cow_page) {
- if (error == -ENODATA)
- clear_user_highpage(vmf->cow_page, vaddr);
- else
- copy_user_highdest(vmf->cow_page, xip_mem, vaddr);
- return VM_FAULT_COWED;
- }
-
- error = vm_insert_mixed(vma, vaddr, xip_pfn);
- mutex_unlock(&mapping->i_mmap_mutex);
- if (error == -ENOMEM)
- return VM_FAULT_OOM;
- /* -EBUSY is fine, somebody else faulted on the same PTE */
- if (error != -EBUSY)
- BUG_ON(error);
- return VM_FAULT_NOPAGE;
-}
-
-static const struct vm_operations_struct xip_file_vm_ops = {
- .fault = xip_file_fault,
- .page_mkwrite = filemap_page_mkwrite,
- .remap_pages = generic_file_remap_pages,
-};
-
-int xip_file_mmap(struct file * file, struct vm_area_struct * vma)
-{
- BUG_ON(!file->f_mapping->a_ops->get_xip_mem);
-
- file_accessed(file);
- vma->vm_ops = &xip_file_vm_ops;
- vma->vm_flags |= VM_MIXEDMAP;
- return 0;
-}
-EXPORT_SYMBOL_GPL(xip_file_mmap);
-
-/*
* truncate a page used for execute in place
* functionality is analog to block_truncate_page but does use get_xip_mem
* to get the page instead of page cache
--
1.8.4.rc3
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