On Tue, Nov 16, 2021 at 08:45:27PM -0800, Darrick J. Wong wrote:

quoted

+/**
+ * folio_zero_segment() - Zero a byte range in a folio.
+ * @folio: The folio to write to.
+ * @start: The first byte to zero.
+ * @end: One more than the last byte in the first range.
+ */
+static inline void folio_zero_segment(struct folio *folio,
+		size_t start, size_t end)
+{
+	zero_user_segments(&folio->page, start, end, 0, 0);
+}
+
+/**
+ * folio_zero_range() - Zero a byte range in a folio.
+ * @folio: The folio to write to.
+ * @start: The first byte to zero.
+ * @length: The number of bytes to zero.
+ */
+static inline void folio_zero_range(struct folio *folio,
+		size_t start, size_t length)
+{
+	zero_user_segments(&folio->page, start, start + length, 0, 0);

At first I thought "Gee, this is wrong, end should be start+length-1!"

Then I looked at zero_user_segments and realized that despite the
parameter name "endi1", it really wants you to tell it the next byte.
Not the end byte of the range you want to zero.

Then I looked at the other two new functions and saw that you documented
this, and now I get why Linus ranted about this some time ago.

The code looks right, but the "end" names rankle me.  Can we please
change them all?  Or at least in the new functions, if you all already
fought a flamewar over this that I'm not aware of?

Change them to what?  I tend to use 'end' to mean 'excluded end' and
'max' to mean 'included end'.  What would you call the excluded end?