xfs: remove indirect calls from xfs_inode_walk{,_ag}

mainline-inclusion
from mainline-v5.13-rc4
commit f427cf5c
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4KIAO
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f427cf5c6236acdf72b4d8564b2e18937c4cc8d8



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It turns out that there is a 1:1 mapping between the execute and goal
parameters that are passed to xfs_inode_walk_ag:

	xfs_blockgc_scan_inode <=> XFS_ICWALK_BLOCKGC
	xfs_dqrele_inode <=> XFS_ICWALK_DQRELE

Because of this exact correspondence, we don't need the execute function
pointer and can replace it with a direct call.

For the price of a forward static declaration, we can eliminate the
indirect function call.  This likely has a negligible impact on
performance (since the execute function runs transactions), but it also
simplifies the function signature.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Lihong Kou <koulihong@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>