| Message ID | 1460493572-31667-1-git-send-email-toshi.kani@hpe.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, 2016-04-12 at 23:01 -0400, Matthew Wilcox wrote: > 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. I thought about it, but I do not think we can use an inline function to an entry point. Thanks, -Toshi -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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(). -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/ext4/file.c b/fs/ext4/file.c index fa2208b..2abc57b 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -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,
To support DAX pmd mappings with unmodified applications, filesystems need to align an mmap address by the pmd size. Call dax_get_unmapped_area() from f_op->get_unmapped_area. Note, there is no change in behavior for a non-DAX file. Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jan Kara <jack@suse.cz> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: <linux-ext4@vger.kernel.org> --- fs/ext4/file.c | 3 +++ 1 file changed, 3 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html