wcte12xp: Use the reglock to protect the framer command lists.

Reduces the number of locks that must be grabbed and released in interrupt
context.  On one 3.06Ghz Intel Xeon test machine, drops the average time in
the interrupt handler from 29.83 us to 23.10 us.

Signed-off-by: Shaun Ruffell <sruffell@digium.com>
Acked-by: Michael Spiceland <mspiceland@digium.com>
Acked-by: Kinsey Moore <kmoore@digium.com>

git-svn-id: http://svn.asterisk.org/svn/dahdi/linux/trunk@9883 a0bf4364-ded3-4de4-8d8a-66a801d63aff

2 files changed, 22 insertions, 36 deletions

diff --git a/drivers/dahdi/wcte12xp/base.c b/drivers/dahdi/wcte12xp/base.c
index 987de9b..235eea3 100644
--- a/drivers/dahdi/wcte12xp/base.c
+++ b/drivers/dahdi/wcte12xp/base.c
@@ -121,38 +121,29 @@ static void free_cmd(struct t1 *wc, struct command *cmd)
 	kmem_cache_free(cmd_cache, cmd);
 }
 
-static struct command *get_pending_cmd(struct t1 *wc)
+static struct command *_get_pending_cmd(struct t1 *wc)
 {
 	struct command *cmd = NULL;
-	unsigned long flags;
-	spin_lock_irqsave(&wc->cmd_list_lock, flags);
 	if (!list_empty(&wc->pending_cmds)) {
 		cmd = list_entry(wc->pending_cmds.next, struct command, node);
 		list_move_tail(&cmd->node, &wc->active_cmds);
 	}
-	spin_unlock_irqrestore(&wc->cmd_list_lock, flags);
 	return cmd;
 }
 
 static void submit_cmd(struct t1 *wc, struct command *cmd)
 {
 	unsigned long flags;
-	spin_lock_irqsave(&wc->cmd_list_lock, flags);
+	spin_lock_irqsave(&wc->reglock, flags);
 	list_add_tail(&cmd->node, &wc->pending_cmds);
-	spin_unlock_irqrestore(&wc->cmd_list_lock, flags);
+	spin_unlock_irqrestore(&wc->reglock, flags);
 }
 
-static void resend_cmds(struct t1 *wc)
+static void _resend_cmds(struct t1 *wc)
 {
-	unsigned long flags;
-	spin_lock_irqsave(&wc->cmd_list_lock, flags);
 	list_splice_init(&wc->active_cmds, &wc->pending_cmds);
-	spin_unlock_irqrestore(&wc->cmd_list_lock, flags);
-
-	spin_lock_irqsave(&wc->reglock, flags);
 	if (wc->vpmadt032)
 		vpmadt032_resend(wc->vpmadt032);
-	spin_unlock_irqrestore(&wc->reglock, flags);
 }
 
 static void cmd_dequeue(struct t1 *wc, unsigned char *eframe, int frame_num, int slot)
@@ -169,7 +160,7 @@ static void cmd_dequeue(struct t1 *wc, unsigned char *eframe, int frame_num, int
 		/* only 6 useable cs slots per */
 
 		/* framer */
-		curcmd = get_pending_cmd(wc);
+		curcmd = _get_pending_cmd(wc);
 		if (curcmd) {
 			curcmd->cs_slot = slot;
 			curcmd->ident = wc->txident;
@@ -201,12 +192,11 @@ static void cmd_dequeue(struct t1 *wc, unsigned char *eframe, int frame_num, int
 static inline void cmd_decipher(struct t1 *wc, const u8 *eframe)
 {
 	struct command *cmd = NULL;
-	unsigned long flags;
 	const int IS_VPM = 0;
 
 	/* Skip audio */
 	eframe += 66;
-	spin_lock_irqsave(&wc->cmd_list_lock, flags);
+
 	while (!list_empty(&wc->active_cmds)) {
 		cmd = list_entry(wc->active_cmds.next, struct command, node);
 		if (cmd->ident != wc->rxident)
@@ -223,12 +213,10 @@ static inline void cmd_decipher(struct t1 *wc, const u8 *eframe)
 			complete(&cmd->complete);
 		}
 	}
-	spin_unlock_irqrestore(&wc->cmd_list_lock, flags);
 }
 
 inline void cmd_decipher_vpmadt032(struct t1 *wc, const u8 *eframe)
 {
-	unsigned long flags;
 	struct vpmadt032 *vpm = wc->vpmadt032;
 	struct vpmadt032_cmd *cmd;
 
@@ -240,14 +228,14 @@ inline void cmd_decipher_vpmadt032(struct t1 *wc, const u8 *eframe)
 		return;
 	}
 
-	spin_lock_irqsave(&vpm->list_lock, flags);
+	spin_lock(&vpm->list_lock);
 	cmd = list_entry(vpm->active_cmds.next, struct vpmadt032_cmd, node);
 	if (wc->rxident == cmd->txident) {
 		list_del_init(&cmd->node);
 	} else {
 		cmd = NULL;
 	}
-	spin_unlock_irqrestore(&vpm->list_lock, flags);
+	spin_unlock(&vpm->list_lock);
 
 	if (!cmd) {
 		return;
@@ -566,12 +554,12 @@ static int t1_getreg(struct t1 *wc, int addr)
 	submit_cmd(wc, cmd);
 	ret = wait_for_completion_interruptible_timeout(&cmd->complete, HZ*10);
 	if (unlikely(!ret)) {
-		spin_lock_irqsave(&wc->cmd_list_lock, flags);
+		spin_lock_irqsave(&wc->reglock, flags);
 		if (!list_empty(&cmd->node)) {
 			/* Since we've removed this command from the list, we
 			 * can go ahead and free it right away. */
 			list_del_init(&cmd->node);
-			spin_unlock_irqrestore(&wc->cmd_list_lock, flags);
+			spin_unlock_irqrestore(&wc->reglock, flags);
 			free_cmd(wc, cmd);
 			if (-ERESTARTSYS != ret) {
 				if (printk_ratelimit()) {
@@ -585,7 +573,7 @@ static int t1_getreg(struct t1 *wc, int addr)
 			/* Looks like this command was removed from the list by
 			 * someone else already. Let's wait for them to complete
 			 * it so that we don't free up the memory. */
-			spin_unlock_irqrestore(&wc->cmd_list_lock, flags);
+			spin_unlock_irqrestore(&wc->reglock, flags);
 			ret = wait_for_completion_timeout(&cmd->complete, HZ*2);
 			WARN_ON(!ret);
 			ret = cmd->data;
@@ -627,9 +615,9 @@ static inline int t1_getpins(struct t1 *wc, int inisr)
 	submit_cmd(wc, cmd);
 	ret = wait_for_completion_interruptible_timeout(&cmd->complete, HZ*2);
 	if (unlikely(!ret)) {
-		spin_lock_irqsave(&wc->cmd_list_lock, flags);
+		spin_lock_irqsave(&wc->reglock, flags);
 		list_del_init(&cmd->node);
-		spin_unlock_irqrestore(&wc->cmd_list_lock, flags);
+		spin_unlock_irqrestore(&wc->reglock, flags);
 		free_cmd(wc, cmd);
 		if (-ERESTARTSYS != ret) {
 			if (printk_ratelimit()) {
@@ -687,10 +675,10 @@ static void free_wc(struct t1 *wc)
 		kfree(wc->ec[x]);
 	}
 
-	spin_lock_irqsave(&wc->cmd_list_lock, flags);
+	spin_lock_irqsave(&wc->reglock, flags);
 	list_splice_init(&wc->active_cmds, &list);
 	list_splice_init(&wc->pending_cmds, &list);
-	spin_unlock_irqrestore(&wc->cmd_list_lock, flags);
+	spin_unlock_irqrestore(&wc->reglock, flags);
 	while (!list_empty(&list)) {
 		cmd = list_entry(list.next, struct command, node);
 		list_del_init(&cmd->node);
@@ -1865,7 +1853,6 @@ static inline void t1_transmitprep(struct t1 *wc, u8 *sframe)
 	int x;
 	int y;
 	int chan;
-	unsigned long flags;
 	u8 *eframe = sframe;
 
 	/* Calculate Transmission */
@@ -1880,6 +1867,7 @@ static inline void t1_transmitprep(struct t1 *wc, u8 *sframe)
 	}
 #endif
 
+	spin_lock(&wc->reglock);
 	for (x = 0; x < DAHDI_CHUNKSIZE; x++) {
 		if (likely(test_bit(INITIALIZED, &wc->bit_flags))) {
 			for (chan = 0; chan < wc->span.channels; chan++)
@@ -1891,10 +1879,8 @@ static inline void t1_transmitprep(struct t1 *wc, u8 *sframe)
 			cmd_dequeue(wc, eframe, x, y);
 
 #ifdef VPM_SUPPORT
-		spin_lock_irqsave(&wc->reglock, flags);
 		if (wc->vpmadt032)
 			cmd_dequeue_vpmadt032(wc, eframe);
-		spin_unlock_irqrestore(&wc->reglock, flags);
 #endif
 
 		if (x < DAHDI_CHUNKSIZE - 1) {
@@ -1903,6 +1889,7 @@ static inline void t1_transmitprep(struct t1 *wc, u8 *sframe)
 		}
 		eframe += (EFRAME_SIZE + EFRAME_GAP);
 	}
+	spin_unlock(&wc->reglock);
 }
 
 /**
@@ -1919,13 +1906,13 @@ static inline bool is_good_frame(const u8 *sframe)
 static inline void t1_receiveprep(struct t1 *wc, const u8* sframe)
 {
 	int x,chan;
-	unsigned long flags;
 	unsigned char expected;
 	const u8 *eframe = sframe;
 
 	if (!is_good_frame(sframe))
 		return;
 
+	spin_lock(&wc->reglock);
 	for (x = 0; x < DAHDI_CHUNKSIZE; x++) {
 		if (likely(test_bit(INITIALIZED, &wc->bit_flags))) {
 			for (chan = 0; chan < wc->span.channels; chan++) {
@@ -1938,7 +1925,7 @@ static inline void t1_receiveprep(struct t1 *wc, const u8* sframe)
 			wc->statreg = eframe[EFRAME_SIZE + 2];
 			if (wc->rxident != expected) {
 				wc->span.irqmisses++;
-				resend_cmds(wc);
+				_resend_cmds(wc);
 				if (unlikely(debug)) {
 					t1_info(wc, "oops: rxident=%d "
 						"expected=%d x=%d\n",
@@ -1948,13 +1935,13 @@ static inline void t1_receiveprep(struct t1 *wc, const u8* sframe)
 		}
 		cmd_decipher(wc, eframe);
 #ifdef VPM_SUPPORT
-		spin_lock_irqsave(&wc->reglock, flags);
 		if (wc->vpmadt032)
 			cmd_decipher_vpmadt032(wc, eframe);
-		spin_unlock_irqrestore(&wc->reglock, flags);
 #endif
 		eframe += (EFRAME_SIZE + EFRAME_GAP);
 	}
+
+	spin_unlock(&wc->reglock);
 	
 	/* echo cancel */
 	if (likely(test_bit(INITIALIZED, &wc->bit_flags))) {
@@ -2228,7 +2215,6 @@ static int __devinit te12xp_init_one(struct pci_dev *pdev, const struct pci_devi
 	memset(wc, 0, sizeof(*wc));
 	wc->ledstate = -1;
 	spin_lock_init(&wc->reglock);
-	spin_lock_init(&wc->cmd_list_lock);
 	INIT_LIST_HEAD(&wc->active_cmds);
 	INIT_LIST_HEAD(&wc->pending_cmds);
 
diff --git a/drivers/dahdi/wcte12xp/wcte12xp.h b/drivers/dahdi/wcte12xp/wcte12xp.h
index fa1afa8..5f6dbce 100644
--- a/drivers/dahdi/wcte12xp/wcte12xp.h
+++ b/drivers/dahdi/wcte12xp/wcte12xp.h
@@ -131,7 +131,7 @@ struct t1 {
 	unsigned long vpm_check;
 	struct work_struct vpm_check_work;
 
-	spinlock_t cmd_list_lock;
+	/* protected by t1.reglock */
 	struct list_head pending_cmds;
 	struct list_head active_cmds;
 	struct timer_list timer;