From 23c560a99d78bddf5c251bfa97bce19e4da4b3f3 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Wed, 15 Apr 2009 22:10:23 +0900
Subject: [PATCH] scatterlist: make sure sg_miter_next() doesn't return 0 sized
mappings
Impact: fix not-so-critical but annoying bug
sg_miter_next() returns 0 sized mapping if there is an zero sized sg
entry in the list or at the end of each iteration. As the users
always check the ->length field, this bug shouldn't be critical other
than causing unnecessary iteration.
Fix it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---
lib/scatterlist.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index b7b449dafbe5..a295e404e908 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -347,9 +347,12 @@ bool sg_miter_next(struct sg_mapping_iter *miter)
sg_miter_stop(miter);
/* get to the next sg if necessary. __offset is adjusted by stop */
- if (miter->__offset == miter->__sg->length && --miter->__nents) {
- miter->__sg = sg_next(miter->__sg);
- miter->__offset = 0;
+ while (miter->__offset == miter->__sg->length) {
+ if (--miter->__nents) {
+ miter->__sg = sg_next(miter->__sg);
+ miter->__offset = 0;
+ } else
+ return false;
}
/* map the next page */
--
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