block: prohibit calls to bio_chain_endio

Shida Zhang · axboe · commit cfdeb588ae1d · 2025-12-09T10:20:03.000-07:00
Now that all potential callers of bio_chain_endio have been
eliminated, completely prohibit any future calls to this function.

Suggested-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Suggested-by: Andreas Gruenbacher &lt;agruenba@redhat.com&gt;
Suggested-by: Christoph Hellwig &lt;hch@infradead.org&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Shida Zhang &lt;zhangshida@kylinos.cn&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
diff --git a/block/bio.c b/block/bio.c
@@ -321,9 +321,13 @@ static struct bio *__bio_chain_endio(struct bio *bio)
 	return parent;
 }
 
+/*
+ * This function should only be used as a flag and must never be called.
+ * If execution reaches here, it indicates a serious programming error.
+ */
 static void bio_chain_endio(struct bio *bio)
 {
-	bio_endio(__bio_chain_endio(bio));
+	BUG();
 }
 
 /**

Original file line number	Diff line number	Diff line change
`@@ -321,9 +321,13 @@ static struct bio __bio_chain_endio(struct bio bio)`
`321`	`321`	`return parent;`
`322`	`322`	`}`
`323`	`323`
	`324`	`+/*`
	`325`	`+ * This function should only be used as a flag and must never be called.`
	`326`	`+ * If execution reaches here, it indicates a serious programming error.`
	`327`	`+ */`
`324`	`328`	`static void bio_chain_endio(struct bio *bio)`
`325`	`329`	`{`
`326`		`- bio_endio(__bio_chain_endio(bio));`
	`330`	`+ BUG();`
`327`	`331`	`}`
`328`	`332`
`329`	`333`	`/**`