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Message-ID: <5759C09F.7020704@broadcom.com>
Date: Thu, 9 Jun 2016 21:16:47 +0200
From: Arend van Spriel <arend.vanspriel@...adcom.com>
To: Rafał Miłecki <zajec5@...il.com>,
Kalle Valo <kvalo@...eaurora.org>
Cc: Brett Rudley <brudley@...adcom.com>,
Arend van Spriel <arend@...adcom.com>,
"Franky (Zhenhui) Lin" <frankyl@...adcom.com>,
Hante Meuleman <meuleman@...adcom.com>,
Pieter-Paul Giesberts <pieterpg@...adcom.com>,
Franky Lin <franky.lin@...adcom.com>,
"open list:BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER"
<linux-wireless@...r.kernel.org>,
"open list:BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER"
<brcm80211-dev-list@...adcom.com>,
"open list:NETWORKING DRIVERS" <netdev@...r.kernel.org>,
open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] brcmfmac: rework function picking free BSS index
On 26-05-16 01:44, Rafał Miłecki wrote:
> The old implementation was overcomplicated and slightly bugged in some
> corner cases.
>
> Consider following state of BSS-es (limited to 6 for simplification):
> drvr->iflist[0]: { bsscfgidx:0, ndev->name:wlan1, }
> drvr->iflist[1]: (null)
> drvr->iflist[2]: { bsscfgidx:2, ndev->name:wlan1-1, }
> drvr->iflist[3]: { bsscfgidx:3, ndev->name:wlan1-2, }
> drvr->iflist[4]: (null)
> drvr->iflist[5]: (null)
> In such case the next AP interface should bsscfgidx 4 (we don't use 1 as
> it's reserved for P2P).
>
> With old code the loop iterations were following:
> [ifidx = 0] [bsscfgidx = 2] [highest = 2]
> [ifidx = 1] [bsscfgidx = 2] [highest = 2] available = true
> [ifidx = 2] [bsscfgidx = 2] [highest = 2] bsscfgidx = highest + 1
> [ifidx = 3] [bsscfgidx = 3] [highest = 2] bsscfgidx = highest + 1
> [ifidx = 4] [bsscfgidx = 3] [highest = 2] available = true
> [ifidx = 5] [bsscfgidx = 3] [highest = 2] available = true
> There were 2 obvious problems:
> 1) Having empty BSS at index 1 was resulting in available being always
> set to true, even if we would run out of BSS-es.
> 2) Calculated bsscfgidx was invalid (3 instead of 4) resulting in driver
> not being able to create the 4th AP interface.
>
> New code is simpler, placed in file where it's really used, handles
> running out of free BSS-es and allows using 4 interfaces at the same
> time. It also looks for the first free BSS instead of one after the last
> in use. It works well with current driver (which doesn't allow deleting
> interfaces) and should be future proof (if we ever allow deleting).
>
> Signed-off-by: Rafał Miłecki <zajec5@...il.com>
> ---
> .../broadcom/brcm80211/brcmfmac/cfg80211.c | 17 ++++++++++++++-
> .../wireless/broadcom/brcm80211/brcmfmac/core.c | 24 ----------------------
> .../wireless/broadcom/brcm80211/brcmfmac/core.h | 1 -
> 3 files changed, 16 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> index 3d09d23..d00eef8 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> @@ -541,6 +541,21 @@ brcmf_cfg80211_update_proto_addr_mode(struct wireless_dev *wdev)
> ADDR_INDIRECT);
> }
>
> +static int brcmf_get_first_free_bsscfgidx(struct brcmf_pub *drvr)
> +{
> + int bsscfgidx;
> +
> + for (bsscfgidx = 0; bsscfgidx < BRCMF_MAX_IFS; bsscfgidx++) {
> + /* bsscfgidx 1 is reserved for legacy P2P */
Hi Rafał,
A bit late as the patch is already applied, but this reserved index is
no longer needed as we removed all trickery that was build on the
assumption that the P2P_DEVICE interface was always in bsscfgidx 1.
Hence this could be removed.
Regards,
Arend
> + if (bsscfgidx == 1)
> + continue;
> + if (!drvr->iflist[bsscfgidx])
> + return bsscfgidx;
> + }
> +
> + return -ENOMEM;
> +}
> +
> static int brcmf_cfg80211_request_ap_if(struct brcmf_if *ifp)
> {
> struct brcmf_mbss_ssid_le mbss_ssid_le;
> @@ -548,7 +563,7 @@ static int brcmf_cfg80211_request_ap_if(struct brcmf_if *ifp)
> int err;
>
> memset(&mbss_ssid_le, 0, sizeof(mbss_ssid_le));
> - bsscfgidx = brcmf_get_next_free_bsscfgidx(ifp->drvr);
> + bsscfgidx = brcmf_get_first_free_bsscfgidx(ifp->drvr);
> if (bsscfgidx < 0)
> return bsscfgidx;
>
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
> index b590499..6a76480 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
> @@ -753,30 +753,6 @@ void brcmf_remove_interface(struct brcmf_if *ifp)
> brcmf_del_if(ifp->drvr, ifp->bsscfgidx);
> }
>
> -int brcmf_get_next_free_bsscfgidx(struct brcmf_pub *drvr)
> -{
> - int ifidx;
> - int bsscfgidx;
> - bool available;
> - int highest;
> -
> - available = false;
> - bsscfgidx = 2;
> - highest = 2;
> - for (ifidx = 0; ifidx < BRCMF_MAX_IFS; ifidx++) {
> - if (drvr->iflist[ifidx]) {
> - if (drvr->iflist[ifidx]->bsscfgidx == bsscfgidx)
> - bsscfgidx = highest + 1;
> - else if (drvr->iflist[ifidx]->bsscfgidx > highest)
> - highest = drvr->iflist[ifidx]->bsscfgidx;
> - } else {
> - available = true;
> - }
> - }
> -
> - return available ? bsscfgidx : -ENOMEM;
> -}
> -
> #ifdef CONFIG_INET
> #define ARPOL_MAX_ENTRIES 8
> static int brcmf_inetaddr_changed(struct notifier_block *nb,
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.h b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.h
> index 647d3cc..2a075c5 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.h
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.h
> @@ -217,7 +217,6 @@ int brcmf_net_attach(struct brcmf_if *ifp, bool rtnl_locked);
> struct brcmf_if *brcmf_add_if(struct brcmf_pub *drvr, s32 bsscfgidx, s32 ifidx,
> bool is_p2pdev, char *name, u8 *mac_addr);
> void brcmf_remove_interface(struct brcmf_if *ifp);
> -int brcmf_get_next_free_bsscfgidx(struct brcmf_pub *drvr);
> void brcmf_txflowblock_if(struct brcmf_if *ifp,
> enum brcmf_netif_stop_reason reason, bool state);
> void brcmf_txfinalize(struct brcmf_if *ifp, struct sk_buff *txp, bool success);
>
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