Messages in this thread | | | Subject | Re: [PATCH v2 2/5] ext4: call dax_get_unmapped_area() for DAX pmd mappings | From | Toshi Kani <> | Date | Wed, 13 Apr 2016 12:52:44 -0600 |
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On Wed, 2016-04-13 at 14:22 -0400, Matthew Wilcox wrote: > On Wed, Apr 13, 2016 at 09:08:36AM -0600, Toshi Kani wrote: > > > > > > > > Could you do something like: > > > > > > #ifdef CONFIG_FS_DAX > > > struct page *read_dax_sector(struct block_device *bdev, sector_t n); > > > +unsigned long dax_get_unmapped_area(struct file *filp, unsigned long > > > addr, > > > + unsigned long len, unsigned long pgoff, unsigned long > > > flags); > > > #else > > > static inline struct page *read_dax_sector(struct block_device > > > *bdev, > > > sector_t n) > > > { > > > return ERR_PTR(-ENXIO); > > > } > > > +#define dax_get_unmapped_area NULL > > > #endif > > > > > > in patch 1/5. Then there's no need for the ifdefs in each > > > filesystem. > > > > I thought about it, but I do not think we can use an inline function to > > an entry point. > > That's not an inline function. It's just NULL. So after the > preprocessor is done with it, it just looks like: > > .get_unmapped_area = NULL, > > and it won't be called by get_unmapped_area().
Oh, I see. Good idea. I will do that.
Thanks, -Toshi
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