On Tue, Apr 12, 2016 at 02:39:29PM -0600, Toshi Kani wrote:
> To support DAX pmd mappings with unmodified applications,
> filesystems need to align an mmap address by the pmd size.
> @@ -708,6 +708,9 @@ const struct file_operations ext4_file_operations = {
> .open = ext4_file_open,
> .release = ext4_release_file,
> .fsync = ext4_sync_file,
> +#ifdef CONFIG_FS_DAX
> + .get_unmapped_area = dax_get_unmapped_area,
> +#endif
> .splice_read = generic_file_splice_read,
> .splice_write = iter_file_splice_write,
> .fallocate = ext4_fallocate,
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.
