dax: Remove pointless writeback from dax_do_io() (c3d98e39) · Commits · 戴 / test

dax_do_io() is calling filemap_write_and_wait() if DIO_LOCKING flags is set. Presumably this was copied over from direct IO code. However DAX inodes have no pagecache pages to write so the call is pointless. Remove it. Reviewed-by:

Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by:

Jan Kara <jack@suse.cz> Signed-off-by:

Vishal Verma <vishal.l.verma@intel.com>

fs/dax.c

+1 −9

Original line number	Diff line number	Diff line
		@@ -268,15 +268,8 @@ ssize_t dax_do_io(struct kiocb iocb, struct inode inode,
		memset(&bh, 0, sizeof(bh));
		bh.b_bdev = inode->i_sb->s_bdev;

		if ((flags & DIO_LOCKING) && iov_iter_rw(iter) == READ) {
		struct address_space *mapping = inode->i_mapping;
		if ((flags & DIO_LOCKING) && iov_iter_rw(iter) == READ)
		inode_lock(inode);
		retval = filemap_write_and_wait_range(mapping, pos, end - 1);
		if (retval) {
		inode_unlock(inode);
		goto out;
		}
		}

		/* Protects against truncate */
		if (!(flags & DIO_SKIP_DIO_COUNT))
		@@ -297,7 +290,6 @@ ssize_t dax_do_io(struct kiocb iocb, struct inode inode,

		if (!(flags & DIO_SKIP_DIO_COUNT))
		inode_dio_end(inode);
		out:
		return retval;
		}
		EXPORT_SYMBOL_GPL(dax_do_io);

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