Patchwork [v5,03/18] wlcore: simplify/fix/optimize reg_ch_conf_pending operations

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Submitter Fenghua Yu
Date March 12, 2019, 11 p.m.
Message ID <1552431636-31511-4-git-send-email-fenghua.yu@intel.com>
Download mbox | patch
Permalink /patch/747805/
State New
Headers show

Comments

Fenghua Yu - March 12, 2019, 11 p.m.
From: Paolo Bonzini <pbonzini@redhat.com>

Bitmaps are defined on unsigned longs, so the usage of u32[2] in the
wlcore driver is incorrect.  As noted by Peter Zijlstra, casting arrays
to a bitmap is incorrect for big-endian architectures.

When looking at it I observed that:

- operations on reg_ch_conf_pending is always under the wl_lock mutex,
so set_bit is overkill

- the only case where reg_ch_conf_pending is accessed a u32 at a time is
unnecessary too.

This patch cleans up everything in this area, and changes tmp_ch_bitmap
to have the proper alignment.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
 drivers/net/wireless/ti/wlcore/cmd.c    | 15 ++++++---------
 drivers/net/wireless/ti/wlcore/wlcore.h |  4 ++--
 2 files changed, 8 insertions(+), 11 deletions(-)
Kalle Valo - March 14, 2019, 1:16 p.m.
Fenghua Yu <fenghua.yu@intel.com> writes:

> From: Paolo Bonzini <pbonzini@redhat.com>
>
> Bitmaps are defined on unsigned longs, so the usage of u32[2] in the
> wlcore driver is incorrect.  As noted by Peter Zijlstra, casting arrays
> to a bitmap is incorrect for big-endian architectures.
>
> When looking at it I observed that:
>
> - operations on reg_ch_conf_pending is always under the wl_lock mutex,
> so set_bit is overkill
>
> - the only case where reg_ch_conf_pending is accessed a u32 at a time is
> unnecessary too.
>
> This patch cleans up everything in this area, and changes tmp_ch_bitmap
> to have the proper alignment.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>

[...]

>  int wlcore_cmd_regdomain_config_locked(struct wl1271 *wl)
>  {
>  	struct wl12xx_cmd_regdomain_dfs_config *cmd = NULL;
>  	int ret = 0, i, b, ch_bit_idx;
> -	u32 tmp_ch_bitmap[2];
> +	u32 tmp_ch_bitmap[2] __aligned(sizeof(unsigned long));
>  	struct wiphy *wiphy = wl->hw->wiphy;
>  	struct ieee80211_supported_band *band;
>  	bool timeout = false;

[...]

> @@ -1754,8 +1751,8 @@ int wlcore_cmd_regdomain_config_locked(struct wl1271 *wl)
>  		goto out;
>  	}
>  
> -	cmd->ch_bit_map1 = cpu_to_le32(tmp_ch_bitmap[0]);
> -	cmd->ch_bit_map2 = cpu_to_le32(tmp_ch_bitmap[1]);
> +	cmd->ch_bit_map1 = tmp_ch_bitmap[0];
> +	cmd->ch_bit_map2 = tmp_ch_bitmap[1];

Will sparse still be happy? AFAICS you are now assigning u32 to __le32:

struct wl12xx_cmd_regdomain_dfs_config {
       struct wl1271_cmd_header header;

       __le32 ch_bit_map1;
       __le32 ch_bit_map2;

Also this doesn't depend on anything else from this patchset, right? So
I could apply this directly?
Fenghua Yu - March 14, 2019, 11:16 p.m.
Hi, Valo,

On Thu, Mar 14, 2019 at 03:16:33PM +0200, Kalle Valo wrote:
> Fenghua Yu <fenghua.yu@intel.com> writes:
> 
> > From: Paolo Bonzini <pbonzini@redhat.com>
> >
> > Bitmaps are defined on unsigned longs, so the usage of u32[2] in the
> > wlcore driver is incorrect.  As noted by Peter Zijlstra, casting arrays
> > to a bitmap is incorrect for big-endian architectures.
> >
> > When looking at it I observed that:
> >
> > - operations on reg_ch_conf_pending is always under the wl_lock mutex,
> > so set_bit is overkill
> >
> > - the only case where reg_ch_conf_pending is accessed a u32 at a time is
> > unnecessary too.
> >
> > This patch cleans up everything in this area, and changes tmp_ch_bitmap
> > to have the proper alignment.
> >
> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> > Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
> 
> [...]
> 
> >  int wlcore_cmd_regdomain_config_locked(struct wl1271 *wl)
> >  {
> >  	struct wl12xx_cmd_regdomain_dfs_config *cmd = NULL;
> >  	int ret = 0, i, b, ch_bit_idx;
> > -	u32 tmp_ch_bitmap[2];
> > +	u32 tmp_ch_bitmap[2] __aligned(sizeof(unsigned long));
> >  	struct wiphy *wiphy = wl->hw->wiphy;
> >  	struct ieee80211_supported_band *band;
> >  	bool timeout = false;
> 
> [...]
> 
> > @@ -1754,8 +1751,8 @@ int wlcore_cmd_regdomain_config_locked(struct wl1271 *wl)
> >  		goto out;
> >  	}
> >  
> > -	cmd->ch_bit_map1 = cpu_to_le32(tmp_ch_bitmap[0]);
> > -	cmd->ch_bit_map2 = cpu_to_le32(tmp_ch_bitmap[1]);
> > +	cmd->ch_bit_map1 = tmp_ch_bitmap[0];
> > +	cmd->ch_bit_map2 = tmp_ch_bitmap[1];
> 
> Will sparse still be happy? AFAICS you are now assigning u32 to __le32:
> 
> struct wl12xx_cmd_regdomain_dfs_config {
>        struct wl1271_cmd_header header;
> 
>        __le32 ch_bit_map1;
>        __le32 ch_bit_map2;

Discussion between Peter and Paolo (https://lkml.org/lkml/2019/3/4/521)
may answer your question.

(Sorry I didn't send to you v4 patch set)

> 
> Also this doesn't depend on anything else from this patchset, right? So
> I could apply this directly?

You are right. This patch doesn't rely on other patches from this patchset.
This patch just fixes a split lock issue. You could apply this directly
without other patches.

Thanks.

-Fenghua
Paolo Bonzini - March 15, 2019, 5:17 p.m.
On 15/03/19 00:16, Fenghua Yu wrote:
> Hi, Valo,
> 
> On Thu, Mar 14, 2019 at 03:16:33PM +0200, Kalle Valo wrote:
>> Fenghua Yu <fenghua.yu@intel.com> writes:
>>
>>> From: Paolo Bonzini <pbonzini@redhat.com>
>>>
>>> Bitmaps are defined on unsigned longs, so the usage of u32[2] in the
>>> wlcore driver is incorrect.  As noted by Peter Zijlstra, casting arrays
>>> to a bitmap is incorrect for big-endian architectures.
>>>
>>> When looking at it I observed that:
>>>
>>> - operations on reg_ch_conf_pending is always under the wl_lock mutex,
>>> so set_bit is overkill
>>>
>>> - the only case where reg_ch_conf_pending is accessed a u32 at a time is
>>> unnecessary too.
>>>
>>> This patch cleans up everything in this area, and changes tmp_ch_bitmap
>>> to have the proper alignment.
>>>
>>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>>> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
>>
>> [...]
>>
>>>  int wlcore_cmd_regdomain_config_locked(struct wl1271 *wl)
>>>  {
>>>  	struct wl12xx_cmd_regdomain_dfs_config *cmd = NULL;
>>>  	int ret = 0, i, b, ch_bit_idx;
>>> -	u32 tmp_ch_bitmap[2];
>>> +	u32 tmp_ch_bitmap[2] __aligned(sizeof(unsigned long));
>>>  	struct wiphy *wiphy = wl->hw->wiphy;
>>>  	struct ieee80211_supported_band *band;
>>>  	bool timeout = false;
>>
>> [...]
>>
>>> @@ -1754,8 +1751,8 @@ int wlcore_cmd_regdomain_config_locked(struct wl1271 *wl)
>>>  		goto out;
>>>  	}
>>>  
>>> -	cmd->ch_bit_map1 = cpu_to_le32(tmp_ch_bitmap[0]);
>>> -	cmd->ch_bit_map2 = cpu_to_le32(tmp_ch_bitmap[1]);
>>> +	cmd->ch_bit_map1 = tmp_ch_bitmap[0];
>>> +	cmd->ch_bit_map2 = tmp_ch_bitmap[1];
>>
>> Will sparse still be happy? AFAICS you are now assigning u32 to __le32:
>>
>> struct wl12xx_cmd_regdomain_dfs_config {
>>        struct wl1271_cmd_header header;
>>
>>        __le32 ch_bit_map1;
>>        __le32 ch_bit_map2;
> 
> Discussion between Peter and Paolo (https://lkml.org/lkml/2019/3/4/521)
> may answer your question.

No, Kalle is right.  You do need to change

-	u32 tmp_ch_bitmap[2];
+	u32 tmp_ch_bitmap[2] __aligned(sizeof(unsigned long));

into

-	u32 tmp_ch_bitmap[2];
+	__le32 tmp_ch_bitmap[2] __aligned(sizeof(unsigned long));

The assignment from wl->reg_ch_conf_pending to tmp_ch_bitmap is fine
because it goes through memcpy.

Paolo

> (Sorry I didn't send to you v4 patch set)
> 
>>
>> Also this doesn't depend on anything else from this patchset, right? So
>> I could apply this directly?
> 
> You are right. This patch doesn't rely on other patches from this patchset.
> This patch just fixes a split lock issue. You could apply this directly
> without other patches.
> 
> Thanks.
> 
> -Fenghua
>
Kalle Valo - March 26, 2019, 7:55 a.m.
Paolo Bonzini <pbonzini@redhat.com> writes:

> On 15/03/19 00:16, Fenghua Yu wrote:
>> Hi, Valo,
>> 
>> On Thu, Mar 14, 2019 at 03:16:33PM +0200, Kalle Valo wrote:
>>> Fenghua Yu <fenghua.yu@intel.com> writes:
>>>
>>>> From: Paolo Bonzini <pbonzini@redhat.com>
>>>>
>>>> Bitmaps are defined on unsigned longs, so the usage of u32[2] in the
>>>> wlcore driver is incorrect.  As noted by Peter Zijlstra, casting arrays
>>>> to a bitmap is incorrect for big-endian architectures.
>>>>
>>>> When looking at it I observed that:
>>>>
>>>> - operations on reg_ch_conf_pending is always under the wl_lock mutex,
>>>> so set_bit is overkill
>>>>
>>>> - the only case where reg_ch_conf_pending is accessed a u32 at a time is
>>>> unnecessary too.
>>>>
>>>> This patch cleans up everything in this area, and changes tmp_ch_bitmap
>>>> to have the proper alignment.
>>>>
>>>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>>>> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
>>>
>>> [...]
>>>
>>>>  int wlcore_cmd_regdomain_config_locked(struct wl1271 *wl)
>>>>  {
>>>>  	struct wl12xx_cmd_regdomain_dfs_config *cmd = NULL;
>>>>  	int ret = 0, i, b, ch_bit_idx;
>>>> -	u32 tmp_ch_bitmap[2];
>>>> +	u32 tmp_ch_bitmap[2] __aligned(sizeof(unsigned long));
>>>>  	struct wiphy *wiphy = wl->hw->wiphy;
>>>>  	struct ieee80211_supported_band *band;
>>>>  	bool timeout = false;
>>>
>>> [...]
>>>
>>>> @@ -1754,8 +1751,8 @@ int wlcore_cmd_regdomain_config_locked(struct wl1271 *wl)
>>>>  		goto out;
>>>>  	}
>>>>  
>>>> -	cmd->ch_bit_map1 = cpu_to_le32(tmp_ch_bitmap[0]);
>>>> -	cmd->ch_bit_map2 = cpu_to_le32(tmp_ch_bitmap[1]);
>>>> +	cmd->ch_bit_map1 = tmp_ch_bitmap[0];
>>>> +	cmd->ch_bit_map2 = tmp_ch_bitmap[1];
>>>
>>> Will sparse still be happy? AFAICS you are now assigning u32 to __le32:
>>>
>>> struct wl12xx_cmd_regdomain_dfs_config {
>>>        struct wl1271_cmd_header header;
>>>
>>>        __le32 ch_bit_map1;
>>>        __le32 ch_bit_map2;
>> 
>> Discussion between Peter and Paolo (https://lkml.org/lkml/2019/3/4/521)
>> may answer your question.
>
> No, Kalle is right.  You do need to change
>
> -	u32 tmp_ch_bitmap[2];
> +	u32 tmp_ch_bitmap[2] __aligned(sizeof(unsigned long));
>
> into
>
> -	u32 tmp_ch_bitmap[2];
> +	__le32 tmp_ch_bitmap[2] __aligned(sizeof(unsigned long));
>
> The assignment from wl->reg_ch_conf_pending to tmp_ch_bitmap is fine
> because it goes through memcpy.

Thanks for confirming, I'll then drop patch 3 and wait for a new
version. IMHO it would be easier to submit this patch separately to
linux-wireless, no need to have within this bigger patchset.

Patch

diff --git a/drivers/net/wireless/ti/wlcore/cmd.c b/drivers/net/wireless/ti/wlcore/cmd.c
index 348be0aed97e..3b9266989afe 100644
--- a/drivers/net/wireless/ti/wlcore/cmd.c
+++ b/drivers/net/wireless/ti/wlcore/cmd.c
@@ -1700,14 +1700,14 @@  void wlcore_set_pending_regdomain_ch(struct wl1271 *wl, u16 channel,
 	ch_bit_idx = wlcore_get_reg_conf_ch_idx(band, channel);
 
 	if (ch_bit_idx >= 0 && ch_bit_idx <= WL1271_MAX_CHANNELS)
-		set_bit(ch_bit_idx, (long *)wl->reg_ch_conf_pending);
+		__set_bit_le(ch_bit_idx, (long *)wl->reg_ch_conf_pending);
 }
 
 int wlcore_cmd_regdomain_config_locked(struct wl1271 *wl)
 {
 	struct wl12xx_cmd_regdomain_dfs_config *cmd = NULL;
 	int ret = 0, i, b, ch_bit_idx;
-	u32 tmp_ch_bitmap[2];
+	u32 tmp_ch_bitmap[2] __aligned(sizeof(unsigned long));
 	struct wiphy *wiphy = wl->hw->wiphy;
 	struct ieee80211_supported_band *band;
 	bool timeout = false;
@@ -1717,7 +1717,7 @@  int wlcore_cmd_regdomain_config_locked(struct wl1271 *wl)
 
 	wl1271_debug(DEBUG_CMD, "cmd reg domain config");
 
-	memset(tmp_ch_bitmap, 0, sizeof(tmp_ch_bitmap));
+	memcpy(tmp_ch_bitmap, wl->reg_ch_conf_pending, sizeof(tmp_ch_bitmap));
 
 	for (b = NL80211_BAND_2GHZ; b <= NL80211_BAND_5GHZ; b++) {
 		band = wiphy->bands[b];
@@ -1738,13 +1738,10 @@  int wlcore_cmd_regdomain_config_locked(struct wl1271 *wl)
 			if (ch_bit_idx < 0)
 				continue;
 
-			set_bit(ch_bit_idx, (long *)tmp_ch_bitmap);
+			__set_bit_le(ch_bit_idx, (long *)tmp_ch_bitmap);
 		}
 	}
 
-	tmp_ch_bitmap[0] |= wl->reg_ch_conf_pending[0];
-	tmp_ch_bitmap[1] |= wl->reg_ch_conf_pending[1];
-
 	if (!memcmp(tmp_ch_bitmap, wl->reg_ch_conf_last, sizeof(tmp_ch_bitmap)))
 		goto out;
 
@@ -1754,8 +1751,8 @@  int wlcore_cmd_regdomain_config_locked(struct wl1271 *wl)
 		goto out;
 	}
 
-	cmd->ch_bit_map1 = cpu_to_le32(tmp_ch_bitmap[0]);
-	cmd->ch_bit_map2 = cpu_to_le32(tmp_ch_bitmap[1]);
+	cmd->ch_bit_map1 = tmp_ch_bitmap[0];
+	cmd->ch_bit_map2 = tmp_ch_bitmap[1];
 	cmd->dfs_region = wl->dfs_region;
 
 	wl1271_debug(DEBUG_CMD,
diff --git a/drivers/net/wireless/ti/wlcore/wlcore.h b/drivers/net/wireless/ti/wlcore/wlcore.h
index dd14850b0603..870eea3e7a27 100644
--- a/drivers/net/wireless/ti/wlcore/wlcore.h
+++ b/drivers/net/wireless/ti/wlcore/wlcore.h
@@ -320,9 +320,9 @@  struct wl1271 {
 	bool watchdog_recovery;
 
 	/* Reg domain last configuration */
-	u32 reg_ch_conf_last[2]  __aligned(8);
+	DECLARE_BITMAP(reg_ch_conf_last, 64);
 	/* Reg domain pending configuration */
-	u32 reg_ch_conf_pending[2];
+	DECLARE_BITMAP(reg_ch_conf_pending, 64);
 
 	/* Pointer that holds DMA-friendly block for the mailbox */
 	void *mbox;