[PATCH v2 11/16] media: sur40: Remove uninitialized_var() usage

Kees Cook
2020-06-20T03:32:39Z

Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings (e.g.
"unused variable"). If the compiler thinks it is uninitialized, either
simply initialize the variable or make compiler changes. As a precursor
to removing[2] this[3] macro[4], just remove this variable since it was
actually unused:

drivers/input/touchscreen/sur40.c:459:6: warning: variable 'packet_id' set but not used [-Wunused-but-set-variable]
459 | u32 packet_id;
| ^~~~~~~~~

However, in keeping with the documentation desires outlined in commit
335abaea7a27 ("Input: sur40 - silence unnecessary noisy debug output"),
comment out the assignment instead of removing it.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Fixes: 335abaea7a27 ("Input: sur40 - silence unnecessary noisy debug output")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/input/touchscreen/sur40.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/input/touchscreen/sur40.c b/drivers/input/touchscreen/sur40.c
index 34d31c7ec8ba..620cdd7d214a 100644
--- a/drivers/input/touchscreen/sur40.c
+++ b/drivers/input/touchscreen/sur40.c
@@ -456,8 +456,6 @@ static void sur40_poll(struct input_dev *input)
{
struct sur40_state *sur40 = input_get_drvdata(input);
int result, bulk_read, need_blobs, packet_blobs, i;
- u32 uninitialized_var(packet_id);
-
struct sur40_header *header = &sur40->bulk_in_buffer->header;
struct sur40_blob *inblob = &sur40->bulk_in_buffer->blobs[0];

@@ -491,7 +489,7 @@ static void sur40_poll(struct input_dev *input)
if (need_blobs == -1) {
need_blobs = le16_to_cpu(header->count);
dev_dbg(sur40->dev, "need %d blobs\n", need_blobs);
- packet_id = le32_to_cpu(header->packet_id);
+ /* packet_id = le32_to_cpu(header->packet_id); */
}

/*
--
2.25.1