sctp: keep fragmentation point aligned to word size

marceloleitner · davem330 · commit 659e0bcaebc4 · 2016-03-20T16:31:12.000-04:00
If the user supply a different fragmentation point or if there is a
network header that cause it to not be aligned, force it to be aligned.

Fragmentation point at a value that is not aligned is not optimal.  It
causes extra padding to be used and has just no pros.

v2:
 - Make use of the new WORD_TRUNC macro

Signed-off-by: Marcelo Ricardo Leitner &lt;marcelo.leitner@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
@@ -431,7 +431,7 @@ static inline int sctp_frag_point(const struct sctp_association *asoc, int pmtu)
 	if (asoc->user_frag)
 		frag = min_t(int, frag, asoc->user_frag);
 
-	frag = min_t(int, frag, SCTP_MAX_CHUNK_LEN);
+	frag = WORD_TRUNC(min_t(int, frag, SCTP_MAX_CHUNK_LEN));
 
 	return frag;
 }

Original file line number	Diff line number	Diff line change
`@@ -431,7 +431,7 @@ static inline int sctp_frag_point(const struct sctp_association *asoc, int pmtu)`
`431`	`431`	`if (asoc->user_frag)`
`432`	`432`	`frag = min_t(int, frag, asoc->user_frag);`
`433`	`433`
`434`		`- frag = min_t(int, frag, SCTP_MAX_CHUNK_LEN);`
	`434`	`+ frag = WORD_TRUNC(min_t(int, frag, SCTP_MAX_CHUNK_LEN));`
`435`	`435`
`436`	`436`	`return frag;`
`437`	`437`	`}`