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Groups > linux.kernel > #1402653 > unrolled thread
| Started by | Heinrich Schuchardt <xypron.glpk@gmx.de> |
|---|---|
| First post | 2016-05-18 01:40 +0200 |
| Last post | 2016-05-19 10:30 +0200 |
| Articles | 2 — 2 participants |
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[PATCH 1/1] iwlwifi: rs: remove superfluous check Heinrich Schuchardt <xypron.glpk@gmx.de> - 2016-05-18 01:40 +0200
Re: [PATCH 1/1] iwlwifi: rs: remove superfluous check "Coelho, Luciano" <luciano.coelho@intel.com> - 2016-05-19 10:30 +0200
| From | Heinrich Schuchardt <xypron.glpk@gmx.de> |
|---|---|
| Date | 2016-05-18 01:40 +0200 |
| Subject | [PATCH 1/1] iwlwifi: rs: remove superfluous check |
| Message-ID | <rzWKJ-2DG-5@gated-at.bofh.it> |
If we dereference a variable anyway in other parts of the code,
there is no need to check against NULL in a single place.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---
drivers/net/wireless/intel/iwlwifi/mvm/rs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/rs.c b/drivers/net/wireless/intel/iwlwifi/mvm/rs.c
index 81dd2f6..bab01ea 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/rs.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/rs.c
@@ -2867,7 +2867,7 @@ static void rs_get_rate(void *mvm_r, struct ieee80211_sta *sta, void *mvm_sta,
/* TODO: handle rate_idx_mask and rate_idx_mcs_mask */
/* Treat uninitialized rate scaling data same as non-existing. */
- if (lq_sta && !lq_sta->pers.drv) {
+ if (!lq_sta->pers.drv) {
IWL_DEBUG_RATE(mvm, "Rate scaling not initialized yet.\n");
mvm_sta = NULL;
}
--
2.1.4
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| From | "Coelho, Luciano" <luciano.coelho@intel.com> |
|---|---|
| Date | 2016-05-19 10:30 +0200 |
| Message-ID | <rArvb-5HV-7@gated-at.bofh.it> |
| In reply to | #1402653 |
On Wed, 2016-05-18 at 01:31 +0200, Heinrich Schuchardt wrote:
> If we dereference a variable anyway in other parts of the code,
> there is no need to check against NULL in a single place.
NACK. This is not true.
If lq_sta is NULL, it means that mvm_sta is also NULL. Then we call
the rate_control_send with mvm_sta == NULL:
if (rate_control_send_low(sta, mvm_sta, txrc))
return;
The rate_control_send_low() function looks like this:
bool rate_control_send_low(struct ieee80211_sta *pubsta,
void *priv_sta,
struct ieee80211_tx_rate_control *txrc)
{
[...]
if (!pubsta || !priv_sta || rc_no_data_or_no_ack_use_min(txrc)) {
[...]
return true;
}
[...]
}
Which means that if priv_sta (aka mvm_sta) is NULL, we will return
without running the rest of rs_get_rate() where lq_sta is accessed
without checks.
I admit that the rs_get_rate() function is a bit hard to read, but
removing the lq_sta check as you did doesn't help, but makes things
worse.
--
Cheers,
Luca.
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