Messages in this thread | | | Date | Wed, 23 Jul 2014 09:55:14 -0400 | From | Matthew Wilcox <> | Subject | Re: [PATCH v8 10/22] Replace the XIP page fault handler with the DAX page fault handler |
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On Wed, Jul 23, 2014 at 03:10:25PM +0300, Kirill A. Shutemov wrote: > > +int dax_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; > > + > > + if (vmf->flags & FAULT_FLAG_WRITE) { > > Nobody seems calls sb_start_pagefault() in fault handler. > Do you mean FAULT_FLAG_MKWRITE?
We need to call sb_start_pagefault() if we're going to make a modification to the filesystem. Admittedly, we don't know if we're going to make a modification at this point, but if we're taking a write fault on a hole, we will be. We can skip the call to sb_start_pagefault() if we're taking a read fault.
> > +int dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, > > + get_block_t get_block) > > +{ > > + return dax_fault(vma, vmf, get_block); > > +} > > +EXPORT_SYMBOL_GPL(dax_mkwrite); > > I don't think we want to introduce new exported symbol just for dummy > wrapper. Just use ".page_mkwrite = foo_fault,". perf and selinux do > this. > Or add #define into header file if you want better readability.
They were different at one time ... agreed, I can just make them an alias for now.
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