On 04/14/2016 05:30 PM, Dan Carpenter wrote:
> Hello Aaron Lu,
>
> The patch 3dc67440d99b: "libata: check zero power ready status for
> ZPODD" from Jan 15, 2013, leads to the following static checker
> warning:
>
> drivers/ata/libata-zpodd.c:97 zpready()
> error: uninitialized symbol 'sense_key'.
>
> drivers/ata/libata-zpodd.c
> 88 /* Test if ODD is zero power ready by sense code */
> 89 static bool zpready(struct ata_device *dev)
This function returns true if ODD is zero power ready, false otherwise.
> 90 {
> 91 u8 sense_key, *sense_buf;
> 92 unsigned int ret, asc, ascq, add_len;
> 93 struct zpodd *zpodd = dev->zpodd;
> 94
> 95 ret = atapi_eh_tur(dev, &sense_key);
> 96
> 97 if (!ret || sense_key != NOT_READY)
> 98 return false;
The pre-condition that the ODD can be considered zero power ready is:
there is no medium inside(hence, atapi_eh_tur should return a failure)
and the sense_key is set to NOT_READY. If the pre-condition is not
met as is checked by the above if, we return false.
>
> It's not clear what is going on here. atapi_eh_tur() returns 0 on
> success or a bit mask on error. If the AC_ERR_DEV (which is BIT(0)) bit
> is set and no other bits then we set "&sense_key" otherwise it is
> uninitialized.
Good point, thanks for the catch.
>
> So maybe the test should be:
>
> if (ret != AC_ERR_DEV || sense_key != NOT_READY)
> return false;
I think I will simply set sense_key to zero beforehand instead of
changing the condition logic here, and it follows the other usage of the
atapi_eh_tur in atapi_eh_clear_ua where the sense_key is also set to 0
beforehand.
>From dda5c9306920ef973c9bf42db7723b86ab8b2930 Mon Sep 17 00:00:00 2001
From: Aaron Lu <aaron.lu@xxxxxxxxx>
Date: Fri, 15 Apr 2016 10:30:32 +0800
Subject: [PATCH] libata: zpodd: initialize sense_key
The sense_key could be uninitialized after the call to atapi_eh_tur so
initialize it beforehand.
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Aaron Lu <aaron.lu@xxxxxxxxx>
---
drivers/ata/libata-zpodd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/ata/libata-zpodd.c b/drivers/ata/libata-zpodd.c
index f3a65a3140d3..b0d3ea5f4769 100644
--- a/drivers/ata/libata-zpodd.c
+++ b/drivers/ata/libata-zpodd.c
@@ -88,7 +88,7 @@ static enum odd_mech_type zpodd_get_mech_type(struct ata_device *dev)
/* Test if ODD is zero power ready by sense code */
static bool zpready(struct ata_device *dev)
{
- u8 sense_key, *sense_buf;
+ u8 sense_key = 0, *sense_buf;
unsigned int ret, asc, ascq, add_len;
struct zpodd *zpodd = dev->zpodd;
--
2.5.5
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