[PATCH] wireless/airo: cache wireless scans
Observed problems when multiple processes request scans and subsequently
scan results. This causes a scan result request to hit card registers
before the scan is complete, returning an incomplete scan list and
possibly making the card very angry. Instead, cache the results of a
wireless scan and serve result requests from the cache, rather than
hitting the hardware for them.
Signed-off-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/airo.c b/drivers/net/wireless/airo.c
index 6f591aba..108d9fe 100644
--- a/drivers/net/wireless/airo.c
+++ b/drivers/net/wireless/airo.c
@@ -770,6 +770,11 @@
} BSSListRid;
typedef struct {
+ BSSListRid bss;
+ struct list_head list;
+} BSSListElement;
+
+typedef struct {
u8 rssipct;
u8 rssidBm;
} tdsRssiEntry;
@@ -1120,6 +1125,8 @@
static u8 airo_rssi_to_dbm (tdsRssiEntry *rssi_rid, u8 rssi);
static u8 airo_dbm_to_pct (tdsRssiEntry *rssi_rid, u8 dbm);
+static void airo_networks_free(struct airo_info *ai);
+
struct airo_info {
struct net_device_stats stats;
struct net_device *dev;
@@ -1151,7 +1158,7 @@
#define FLAG_COMMIT 13
#define FLAG_RESET 14
#define FLAG_FLASHING 15
-#define JOB_MASK 0x1ff0000
+#define JOB_MASK 0x2ff0000
#define JOB_DIE 16
#define JOB_XMIT 17
#define JOB_XMIT11 18
@@ -1161,6 +1168,7 @@
#define JOB_EVENT 22
#define JOB_AUTOWEP 23
#define JOB_WSTATS 24
+#define JOB_SCAN_RESULTS 25
int (*bap_read)(struct airo_info*, u16 *pu16Dst, int bytelen,
int whichbap);
unsigned short *flash;
@@ -1177,7 +1185,7 @@
} xmit, xmit11;
struct net_device *wifidev;
struct iw_statistics wstats; // wireless stats
- unsigned long scan_timestamp; /* Time started to scan */
+ unsigned long scan_timeout; /* Time scan should be read */
struct iw_spy_data spy_data;
struct iw_public_data wireless_data;
/* MIC stuff */
@@ -1199,6 +1207,10 @@
APListRid *APList;
#define PCI_SHARED_LEN 2*MPI_MAX_FIDS*PKTSIZE+RIDSIZE
char proc_name[IFNAMSIZ];
+
+ struct list_head network_list;
+ struct list_head network_free_list;
+ BSSListElement *networks;
};
static inline int bap_read(struct airo_info *ai, u16 *pu16Dst, int bytelen,
@@ -2381,6 +2393,8 @@
dev_kfree_skb(skb);
}
+ airo_networks_free (ai);
+
kfree(ai->flash);
kfree(ai->rssi);
kfree(ai->APList);
@@ -2687,6 +2701,42 @@
return 0;
}
+#define MAX_NETWORK_COUNT 64
+static int airo_networks_allocate(struct airo_info *ai)
+{
+ if (ai->networks)
+ return 0;
+
+ ai->networks =
+ kzalloc(MAX_NETWORK_COUNT * sizeof(BSSListElement),
+ GFP_KERNEL);
+ if (!ai->networks) {
+ airo_print_warn(ai->dev->name, "Out of memory allocating beacons");
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void airo_networks_free(struct airo_info *ai)
+{
+ if (!ai->networks)
+ return;
+ kfree(ai->networks);
+ ai->networks = NULL;
+}
+
+static void airo_networks_initialize(struct airo_info *ai)
+{
+ int i;
+
+ INIT_LIST_HEAD(&ai->network_free_list);
+ INIT_LIST_HEAD(&ai->network_list);
+ for (i = 0; i < MAX_NETWORK_COUNT; i++)
+ list_add_tail(&ai->networks[i].list,
+ &ai->network_free_list);
+}
+
static struct net_device *_init_airo_card( unsigned short irq, int port,
int is_pcmcia, struct pci_dev *pci,
struct device *dmdev )
@@ -2728,6 +2778,10 @@
if (rc)
goto err_out_thr;
+ if (airo_networks_allocate (ai))
+ goto err_out_unlink;
+ airo_networks_initialize (ai);
+
/* The Airo-specific entries in the device structure. */
if (test_bit(FLAG_MPI,&ai->flags)) {
skb_queue_head_init (&ai->txq);
@@ -2749,7 +2803,6 @@
SET_NETDEV_DEV(dev, dmdev);
-
reset_card (dev, 1);
msleep(400);
@@ -2892,6 +2945,65 @@
wireless_send_event(dev, SIOCGIWAP, &wrqu, NULL);
}
+static void airo_process_scan_results (struct airo_info *ai) {
+ union iwreq_data wrqu;
+ BSSListRid BSSList;
+ int rc;
+ BSSListElement * loop_net;
+ BSSListElement * tmp_net;
+
+ /* Blow away current list of scan results */
+ list_for_each_entry_safe (loop_net, tmp_net, &ai->network_list, list) {
+ list_move_tail (&loop_net->list, &ai->network_free_list);
+ /* Don't blow away ->list, just BSS data */
+ memset (loop_net, 0, sizeof (loop_net->bss));
+ }
+
+ /* Try to read the first entry of the scan result */
+ rc = PC4500_readrid(ai, RID_BSSLISTFIRST, &BSSList, sizeof(BSSList), 0);
+ if((rc) || (BSSList.index == 0xffff)) {
+ /* No scan results */
+ goto out;
+ }
+
+ /* Read and parse all entries */
+ tmp_net = NULL;
+ while((!rc) && (BSSList.index != 0xffff)) {
+ /* Grab a network off the free list */
+ if (!list_empty(&ai->network_free_list)) {
+ tmp_net = list_entry(ai->network_free_list.next,
+ BSSListElement, list);
+ list_del(ai->network_free_list.next);
+ }
+
+ if (tmp_net != NULL) {
+ memcpy(tmp_net, &BSSList, sizeof(tmp_net->bss));
+ list_add_tail(&tmp_net->list, &ai->network_list);
+ tmp_net = NULL;
+ }
+
+ /* Read next entry */
+ rc = PC4500_readrid(ai, RID_BSSLISTNEXT,
+ &BSSList, sizeof(BSSList), 0);
+ }
+
+out:
+ ai->scan_timeout = 0;
+ clear_bit(JOB_SCAN_RESULTS, &ai->flags);
+ up(&ai->sem);
+
+ /* Send an empty event to user space.
+ * We don't send the received data on
+ * the event because it would require
+ * us to do complex transcoding, and
+ * we want to minimise the work done in
+ * the irq handler. Use a request to
+ * extract the data - Jean II */
+ wrqu.data.length = 0;
+ wrqu.data.flags = 0;
+ wireless_send_event(ai->dev, SIOCGIWSCAN, &wrqu, NULL);
+}
+
static int airo_thread(void *data) {
struct net_device *dev = data;
struct airo_info *ai = dev->priv;
@@ -2921,13 +3033,26 @@
set_current_state(TASK_INTERRUPTIBLE);
if (ai->flags & JOB_MASK)
break;
- if (ai->expires) {
- if (time_after_eq(jiffies,ai->expires)){
+ if (ai->expires || ai->scan_timeout) {
+ if (ai->scan_timeout &&
+ time_after_eq(jiffies,ai->scan_timeout)){
+ set_bit(JOB_SCAN_RESULTS,&ai->flags);
+ break;
+ } else if (ai->expires &&
+ time_after_eq(jiffies,ai->expires)){
set_bit(JOB_AUTOWEP,&ai->flags);
break;
}
if (!signal_pending(current)) {
- schedule_timeout(ai->expires - jiffies);
+ unsigned long wake_at;
+ if (!ai->expires || !ai->scan_timeout) {
+ wake_at = max(ai->expires,
+ ai->scan_timeout);
+ } else {
+ wake_at = min(ai->expires,
+ ai->scan_timeout);
+ }
+ schedule_timeout(wake_at - jiffies);
continue;
}
} else if (!signal_pending(current)) {
@@ -2970,6 +3095,10 @@
airo_send_event(dev);
else if (test_bit(JOB_AUTOWEP, &ai->flags))
timer_func(dev);
+ else if (test_bit(JOB_SCAN_RESULTS, &ai->flags))
+ airo_process_scan_results(ai);
+ else /* Shouldn't get here, but we make sure to unlock */
+ up(&ai->sem);
}
complete_and_exit (&ai->thr_exited, 0);
}
@@ -3064,19 +3193,15 @@
* and reassociations as valid status
* Jean II */
if(newStatus == ASSOCIATED) {
- if (apriv->scan_timestamp) {
- /* Send an empty event to user space.
- * We don't send the received data on
- * the event because it would require
- * us to do complex transcoding, and
- * we want to minimise the work done in
- * the irq handler. Use a request to
- * extract the data - Jean II */
- wrqu.data.length = 0;
- wrqu.data.flags = 0;
- wireless_send_event(dev, SIOCGIWSCAN, &wrqu, NULL);
- apriv->scan_timestamp = 0;
+#if 0
+ /* FIXME: Grabbing scan results here
+ * seems to be too early??? Just wait for
+ * timeout instead. */
+ if (apriv->scan_timeout > 0) {
+ set_bit(JOB_SCAN_RESULTS, &apriv->flags);
+ wake_up_interruptible(&apriv->thr_wait);
}
+#endif
if (down_trylock(&apriv->sem) != 0) {
set_bit(JOB_EVENT, &apriv->flags);
wake_up_interruptible(&apriv->thr_wait);
@@ -6992,6 +7117,7 @@
struct airo_info *ai = dev->priv;
Cmd cmd;
Resp rsp;
+ int wake = 0;
/* Note : you may have realised that, as this is a SET operation,
* this is privileged and therefore a normal user can't
@@ -7001,17 +7127,25 @@
* Jean II */
if (ai->flags & FLAG_RADIO_MASK) return -ENETDOWN;
+ if (down_interruptible(&ai->sem))
+ return -ERESTARTSYS;
+
+ /* If there's already a scan in progress, don't
+ * trigger another one. */
+ if (ai->scan_timeout > 0)
+ goto out;
+
/* Initiate a scan command */
memset(&cmd, 0, sizeof(cmd));
cmd.cmd=CMD_LISTBSS;
- if (down_interruptible(&ai->sem))
- return -ERESTARTSYS;
issuecommand(ai, &cmd, &rsp);
- ai->scan_timestamp = jiffies;
+ ai->scan_timeout = RUN_AT(3*HZ);
+ wake = 1;
+
+out:
up(&ai->sem);
-
- /* At this point, just return to the user. */
-
+ if (wake)
+ wake_up_interruptible(&ai->thr_wait);
return 0;
}
@@ -7131,59 +7265,38 @@
char *extra)
{
struct airo_info *ai = dev->priv;
- BSSListRid BSSList;
- int rc;
+ BSSListElement *net;
+ int err = 0;
char *current_ev = extra;
- /* When we are associated again, the scan has surely finished.
- * Just in case, let's make sure enough time has elapsed since
- * we started the scan. - Javier */
- if(ai->scan_timestamp && time_before(jiffies,ai->scan_timestamp+3*HZ)) {
- /* Important note : we don't want to block the caller
- * until results are ready for various reasons.
- * First, managing wait queues is complex and racy
- * (there may be multiple simultaneous callers).
- * Second, we grab some rtnetlink lock before comming
- * here (in dev_ioctl()).
- * Third, the caller can wait on the Wireless Event
- * - Jean II */
+ /* If a scan is in-progress, return -EAGAIN */
+ if (ai->scan_timeout > 0)
return -EAGAIN;
- }
- ai->scan_timestamp = 0;
- /* There's only a race with proc_BSSList_open(), but its
- * consequences are begnign. So I don't bother fixing it - Javier */
+ if (down_interruptible(&ai->sem))
+ return -EAGAIN;
- /* Try to read the first entry of the scan result */
- rc = PC4500_readrid(ai, RID_BSSLISTFIRST, &BSSList, sizeof(BSSList), 1);
- if((rc) || (BSSList.index == 0xffff)) {
- /* Client error, no scan results...
- * The caller need to restart the scan. */
- return -ENODATA;
- }
-
- /* Read and parse all entries */
- while((!rc) && (BSSList.index != 0xffff)) {
+ list_for_each_entry (net, &ai->network_list, list) {
/* Translate to WE format this entry */
current_ev = airo_translate_scan(dev, current_ev,
extra + dwrq->length,
- &BSSList);
+ &net->bss);
/* Check if there is space for one more entry */
if((extra + dwrq->length - current_ev) <= IW_EV_ADDR_LEN) {
/* Ask user space to try again with a bigger buffer */
- return -E2BIG;
+ err = -E2BIG;
+ goto out;
}
-
- /* Read next entry */
- rc = PC4500_readrid(ai, RID_BSSLISTNEXT,
- &BSSList, sizeof(BSSList), 1);
}
+
/* Length of data */
dwrq->length = (current_ev - extra);
dwrq->flags = 0; /* todo */
- return 0;
+out:
+ up(&ai->sem);
+ return err;
}
/*------------------------------------------------------------------*/