From: Christian Lamparter Date: Mon, 3 Dec 2012 17:48:05 +0000 (+0100) Subject: carl9170: explain why sta cannot be NULL for ampdus X-Git-Tag: omap-for-v3.8/fixes-for-merge-window-v4-signed~45^2~56^2^2~32 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1981e881fd32160bf886a09b12794c640aafffb3;p=pandora-kernel.git carl9170: explain why sta cannot be NULL for ampdus Dan Carpenter reported that smatch detected a potential problem with the code [1]: drivers/net/wireless/ath/carl9170/tx.c:1488 carl9170_op_tx() error: we previously assumed 'sta' could be null (see line 1482) drivers/net/wireless/ath/carl9170/tx.c 1482 if (sta) { ^^^^^ New check. [...] 1485 } 1487 if (info->flags & IEEE80211_TX_CTL_AMPDU) { 1488 run = carl9170_tx_ampdu_queue(ar, sta, skb); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Old dereference of "sta" inside the call to carl9170_tx_ampdu_queue(). A range of solutions have been discussed in [2] and we agreed on the following: " > we might as well add a comment to carl9170_tx_ampdu_queue > and explain the situation [in a way that's obvious to a > human reader]. This way we can save the "if"... which is > a small win since carl9170_op_tx is sort of a hot-path. Putting a comment there is fine. Without the comment it's easy for a human reader to get confused why the check is there. So long as humans can read the code, that's all that matters." [1] [2] Reported-by: Dan Carpenter Signed-off-by: Christian Lamparter Signed-off-by: John W. Linville --- Reading git-diff-tree failed