[PATCH 4/7] xfs: DAX does not use IO completion callbacks

[Dave Chinner <david@xxxxxxxxxxxxx>]

From: Dave Chinner <dchinner@xxxxxxxxxx>

For DAX, we are now doing block zeroing during allocation. This
means we no longer need a special DAX fault IO completion callback
to do unwritten extent conversion. Because mmap never extends the
file size (it SEGVs the process) we don't need a callback to update
the file size, either. Hence we can remove the completion callbacks
from the __dax_fault and __dax_mkwrite calls.

Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
Signed-off-by: Dave Chinner <david@xxxxxxxxxxxxx>
---
 fs/xfs/xfs_aops.c | 39 ---------------------------------------
 fs/xfs/xfs_aops.h |  1 -
 fs/xfs/xfs_file.c |  5 ++---
 3 files changed, 2 insertions(+), 43 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 7b4f849..29e7e5d 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -1666,45 +1666,6 @@ xfs_end_io_direct_write(
        __xfs_end_io_direct_write(inode, ioend, offset, size);
 }
 
-/*
- * For DAX we need a mapping buffer callback for unwritten extent conversion
- * when page faults allocate blocks and then zero them. Note that in this
- * case the mapping indicated by the ioend may extend beyond EOF. We most
- * definitely do not want to extend EOF here, so we trim back the ioend size to
- * EOF.
- */
-#ifdef CONFIG_FS_DAX
-void
-xfs_end_io_dax_write(
-       struct buffer_head      *bh,
-       int                     uptodate)
-{
-       struct xfs_ioend        *ioend = bh->b_private;
-       struct inode            *inode = ioend->io_inode;
-       ssize_t                 size = ioend->io_size;
-
-       ASSERT(IS_DAX(ioend->io_inode));
-
-       /* if there was an error zeroing, then don't convert it */
-       if (!uptodate)
-               ioend->io_error = -EIO;
-
-       /*
-        * Trim update to EOF, so we don't extend EOF during unwritten extent
-        * conversion of partial EOF blocks.
-        */
-       spin_lock(&XFS_I(inode)->i_flags_lock);
-       if (ioend->io_offset + size > i_size_read(inode))
-               size = i_size_read(inode) - ioend->io_offset;
-       spin_unlock(&XFS_I(inode)->i_flags_lock);
-
-       __xfs_end_io_direct_write(inode, ioend, ioend->io_offset, size);
-
-}
-#else
-void xfs_end_io_dax_write(struct buffer_head *bh, int uptodate) { }
-#endif
-
 static inline ssize_t
 xfs_vm_do_dio(
        struct inode            *inode,
diff --git a/fs/xfs/xfs_aops.h b/fs/xfs/xfs_aops.h
index d39ba25..f6ffc9a 100644
--- a/fs/xfs/xfs_aops.h
+++ b/fs/xfs/xfs_aops.h
@@ -60,7 +60,6 @@ int   xfs_get_blocks_direct(struct inode *inode, sector_t 
offset,
                              struct buffer_head *map_bh, int create);
 int    xfs_get_blocks_dax_fault(struct inode *inode, sector_t offset,
                                 struct buffer_head *map_bh, int create);
-void   xfs_end_io_dax_write(struct buffer_head *bh, int uptodate);
 
 extern void xfs_count_page_state(struct page *, int *, int *);
 
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 7f873bc..403151a 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1508,8 +1508,7 @@ xfs_filemap_page_mkwrite(
        xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
 
        if (IS_DAX(inode)) {
-               ret = __dax_mkwrite(vma, vmf, xfs_get_blocks_dax_fault,
-                                   xfs_end_io_dax_write);
+               ret = __dax_mkwrite(vma, vmf, xfs_get_blocks_dax_fault, NULL);
        } else {
                ret = __block_page_mkwrite(vma, vmf, xfs_get_blocks);
                ret = block_page_mkwrite_return(ret);
@@ -1571,7 +1570,7 @@ xfs_filemap_pmd_fault(
        file_update_time(vma->vm_file);
        xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
        ret = __dax_pmd_fault(vma, addr, pmd, flags, xfs_get_blocks_dax_fault,
-                                   xfs_end_io_dax_write);
+                             NULL);
        xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
        sb_end_pagefault(inode->i_sb);
 
-- 
2.5.0