LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
* [PATCH] media: smiapp: fix timeout checking in smiapp_read_nvm
@ 2018-04-25 15:04 Colin King
  0 siblings, 0 replies; only message in thread
From: Colin King @ 2018-04-25 15:04 UTC (permalink / raw)
  To: Sakari Ailus, Mauro Carvalho Chehab, linux-media
  Cc: kernel-janitors, linux-kernel

From: Colin Ian King <colin.king@canonical.com>

The current code decrements the timeout counter i and the end of
each loop i is incremented, so the check for timeout will always
be false and hence the timeout mechanism is just a dead code path.
Potentially, if the RD_READY bit is not set, we could end up in
an infinite loop.

Fix this so the timeout starts from 1000 and decrements to zero,
if at the end of the loop i is zero we have a timeout condition.

Detected by CoverityScan, CID#1324008 ("Logically dead code")

Fixes: ccfc97bdb5ae ("[media] smiapp: Add driver")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/media/i2c/smiapp/smiapp-core.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/media/i2c/smiapp/smiapp-core.c b/drivers/media/i2c/smiapp/smiapp-core.c
index 3b7ace395ee6..e1f8208581aa 100644
--- a/drivers/media/i2c/smiapp/smiapp-core.c
+++ b/drivers/media/i2c/smiapp/smiapp-core.c
@@ -1001,7 +1001,7 @@ static int smiapp_read_nvm(struct smiapp_sensor *sensor,
 		if (rval)
 			goto out;
 
-		for (i = 0; i < 1000; i++) {
+		for (i = 1000; i > 0; i--) {
 			rval = smiapp_read(
 				sensor,
 				SMIAPP_REG_U8_DATA_TRANSFER_IF_1_STATUS, &s);
@@ -1012,11 +1012,10 @@ static int smiapp_read_nvm(struct smiapp_sensor *sensor,
 			if (s & SMIAPP_DATA_TRANSFER_IF_1_STATUS_RD_READY)
 				break;
 
-			if (--i == 0) {
-				rval = -ETIMEDOUT;
-				goto out;
-			}
-
+		}
+		if (!i) {
+			rval = -ETIMEDOUT;
+			goto out;
 		}
 
 		for (i = 0; i < SMIAPP_NVM_PAGE_SIZE; i++) {
-- 
2.17.0

^ permalink raw reply	[flat|nested] only message in thread

only message in thread, other threads:[~2018-04-25 15:04 UTC | newest]

Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-04-25 15:04 [PATCH] media: smiapp: fix timeout checking in smiapp_read_nvm Colin King

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).