[PATCH] check for null while iterating over a scatterlist table

[PATCH] check for null while iterating over a scatterlist table

[Rajnikant Bhojani]

during iterating over a scatterlist table also need to check for NULL
along with number of scatterlist

Signed-off-by: Rajnikant Bhojani <rajnikant.bhojani@sibridgetech.com>
---

 include/linux/scatterlist.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index cb3c8fe..f8dce12 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -146,7 +146,7 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
  * Loop over each sg element, following the pointer to a new list if necessary
  */
 #define for_each_sg(sglist, sg, nr, __i)	\
-	for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg))
+	for (__i = 0, sg = (sglist); __i < (nr) && sg; __i++, sg = sg_next(sg))
 
 /**
  * sg_chain - Chain two sglists together
-- 
2.7.4

Re: [PATCH] check for null while iterating over a scatterlist table

[Christoph Hellwig]

On Tue, Apr 25, 2017 at 01:08:49PM +0530, Rajnikant Bhojani wrote:
> during iterating over a scatterlist table also need to check for NULL
> along with number of scatterlist

Not sure this is a good idea.  Callers expect to iterate over the
full number in general.  Exiting early just papers over the bug
instead of fixing it.  A WARN_ON for this case might be a better idea.

[PATCH] check for null while iterating over a scatterlist table

[Rajnikant Bhojani]

during iterating over a scatterlist table also need to check for NULL
along with number of scatterlist

Signed-off-by: Rajnikant Bhojani <rajnikant.bhojani@sibridgetech.com>
---

 include/linux/scatterlist.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index cb3c8fe..f8dce12 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -146,7 +146,7 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
  * Loop over each sg element, following the pointer to a new list if necessary
  */
 #define for_each_sg(sglist, sg, nr, __i)	\
-	for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg))
+	for (__i = 0, sg = (sglist); __i < (nr) && sg; __i++, sg = sg_next(sg))
 
 /**
  * sg_chain - Chain two sglists together
-- 
2.7.4