Re: [PATCH] staging: rtl8188eu: rtw_mlme.c: fix sparse warning

From: Larry Finger
Date: Mon Dec 29 2014 - 01:20:44 EST


On 12/28/2014 11:47 PM, Serguey Parkhomovsky wrote:
Fixes the following sparse warning for rtw_mlme.c:

drivers/staging/rtl8188eu/core/rtw_mlme.c:810:9: warning: context imbalance in 'rtw_free_assoc_resources' - different lock contexts for basic block

Signed-off-by: Serguey Parkhomovsky <sergueyparkhomovsky@xxxxxxxxx>
---
drivers/staging/rtl8188eu/core/rtw_mlme.c | 37 ++++++++++++++++++++-----------
1 file changed, 24 insertions(+), 13 deletions(-)

Are these many changes needed just because Sparse is not smart enough to understand that the following does not really have a context imbalance:

if (lock_scanned_queue)
spin_lock_bh(&(pmlmepriv->scanned_queue.lock));
.....
.....

if (lock_scanned_queue)
spin_unlock_bh(&pmlmepriv->scanned_queue.lock);

Nothing in the middle touches lock_scanned_queue, thus if the spin lock and unlock operations will be paired. That is all that is important. The fact that some tool objects to this construct means that the tool is broken, not the code.

In my mind, Sparse warnings/errors/checks are in place to alert you to a possible problem. If they point to white space issues, then you fix them. If they point to lines that are too long, then you see if you can shorten them without harming the readability. In any case, judgement should be used before blindly trying to silence the warning.

For those reasons, NACK.

Larry


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