Re: [PATCH 28/45] xfs: introduce xlog_write_single()

On Mon, Mar 08, 2021 at 06:39:27PM -0800, Darrick J. Wong wrote:

On Fri, Mar 05, 2021 at 04:11:26PM +1100, Dave Chinner wrote:

quoted

From: Dave Chinner <redacted>

Introduce an optimised version of xlog_write() that is used when the
entire write will fit in a single iclog. This greatly simplifies the
implementation of writing a log vector chain into an iclog, and sets
the ground work for a much more understandable xlog_write()
implementation.

Signed-off-by: Dave Chinner <redacted>
---
 fs/xfs/xfs_log.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 56 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 22f97914ab99..590c1e6db475 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c

@@ -2214,6 +2214,52 @@ xlog_write_copy_finish(
 	return error;
 }
 
+/*
+ * Write log vectors into a single iclog which is guaranteed by the caller
+ * to have enough space to write the entire log vector into. Return the number
+ * of log vectors written into the iclog.
+ */
+static int
+xlog_write_single(
+	struct xfs_log_vec	*log_vector,
+	struct xlog_ticket	*ticket,
+	struct xlog_in_core	*iclog,
+	uint32_t		log_offset,
+	uint32_t		len)
+{
+	struct xfs_log_vec	*lv = log_vector;
+	void			*ptr;
+	int			index = 0;
+	int			record_cnt = 0;

Any reason these (and the return type) can't be unsigned?  I don't think
negative indices or record counts have any meaning, right?

Correct, but I'm going to ignore that because the next patch already
addresses both of these things. Changing it here just means a
massive reject of the next patch where it replaces the return value
with a log vector, and the record count moves to a function
parameter that is, indeed, a uint32_t.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com