From: Marco Stornelli <marco.stornelli@xxxxxxxxx>
There aren't sufficient sync points for a fs for xip operations. In
particular for the mmap case. It can be not sufficient to lock/unlock
to do some operation inside get_xip_mem callback. For xip_file_read
it's really easy to write a fs specific wrapper, xip_file_write hold
i_mutex so no problem. With this patch it's possible to reuse the
generic xip_file_fault, using a wrapper function in a fs, without to
reinvent the wheel.
Signed-off-by: Marco Stornelli <marco.stornelli@xxxxxxxxx>
---
--- linux-3.1-rc4/mm/filemap_xip.c.orig 2011-09-17 13:58:44.000000000 +0200
+++ linux-3.1-rc4/mm/filemap_xip.c 2011-09-17 13:59:31.000000000 +0200
@@ -218,7 +218,7 @@ retry:
*
* 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)
+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;
@@ -296,6 +296,7 @@ out:
return ret;
}
}
+EXPORT_SYMBOL_GPL(xip_file_fault);
static const struct vm_operations_struct xip_file_vm_ops = {
.fault = xip_file_fault,
--- linux-3.1-rc4/include/linux/fs.h.orig 2011-09-17 13:59:01.000000000 +0200
+++ linux-3.1-rc4/include/linux/fs.h 2011-09-17 14:00:35.000000000 +0200
@@ -409,6 +409,7 @@ struct pipe_inode_info;
struct poll_table_struct;
struct kstatfs;
struct vm_area_struct;
+struct vm_fault;
struct vfsmount;
struct cred;
@@ -2403,6 +2404,7 @@ extern int nonseekable_open(struct inode
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 int xip_file_fault(struct vm_area_struct *vma, struct vm_fault *vmf);
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);
--
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