IB/ipath: Make send buffers available for kernel if not allocated to user

A fixed partitioning of send buffers is determined at driver load time
for user processes and kernel use.  Since send buffers are a scarce
resource, it makes sense to allow the kernel to use the buffers if they
are not in use by a user process.

Also, eliminate code duplication for ipath_force_pio_avail_update().
Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/ipath/ipath_diag.c

@@ -439,7 +439,9 @@ static ssize_t ipath_diagpkt_write(struct file *fp,
 		goto bail;
 	}
 
-	piobuf = ipath_getpiobuf(dd, &pbufn);
+	plen >>= 2;		/* in dwords */
+
+	piobuf = ipath_getpiobuf(dd, plen, &pbufn);
 	if (!piobuf) {
 		ipath_cdbg(VERBOSE, "No PIO buffers avail unit for %u\n",
 			   dd->ipath_unit);
@@ -449,8 +451,6 @@ static ssize_t ipath_diagpkt_write(struct file *fp,
 	/* disarm it just to be extra sure */
 	ipath_disarm_piobufs(dd, pbufn, 1);
 
-	plen >>= 2;		/* in dwords */
-
 	if (ipath_debug & __IPATH_PKTDBG)
 		ipath_cdbg(VERBOSE, "unit %u 0x%x+1w pio%d\n",
 			   dd->ipath_unit, plen - 1, pbufn);

drivers/infiniband/hw/ipath/ipath_file_ops.c

@@ -1603,6 +1603,9 @@ static int try_alloc_port(struct ipath_devdata *dd, int port,
 		port_fp(fp) = pd;
 		pd->port_pid = current->pid;
 		strncpy(pd->port_comm, current->comm, sizeof(pd->port_comm));
+		ipath_chg_pioavailkernel(dd,
+			dd->ipath_pbufsport * (pd->port_port - 1),
+			dd->ipath_pbufsport, 0);
 		ipath_stats.sps_ports++;
 		ret = 0;
 	} else
@@ -2081,6 +2084,7 @@ static int ipath_close(struct inode *in, struct file *fp)
 
 		i = dd->ipath_pbufsport * (port - 1);
 		ipath_disarm_piobufs(dd, i, dd->ipath_pbufsport);
+		ipath_chg_pioavailkernel(dd, i, dd->ipath_pbufsport, 1);
 
 		dd->ipath_f_clear_tids(dd, pd->port_port);
 
@@ -2145,21 +2149,6 @@ static int ipath_get_slave_info(struct ipath_portdata *pd,
 	return ret;
 }
 
-static int ipath_force_pio_avail_update(struct ipath_devdata *dd)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags);
-	ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
-		dd->ipath_sendctrl & ~INFINIPATH_S_PIOBUFAVAILUPD);
-	ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
-	ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl, dd->ipath_sendctrl);
-	ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
-	spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags);
-
-	return 0;
-}
-
 static ssize_t ipath_write(struct file *fp, const char __user *data,
 			   size_t count, loff_t *off)
 {
@@ -2304,7 +2293,7 @@ static ssize_t ipath_write(struct file *fp, const char __user *data,
 					   cmd.cmd.slave_mask_addr);
 		break;
 	case IPATH_CMD_PIOAVAILUPD:
-		ret = ipath_force_pio_avail_update(pd->port_dd);
+		ipath_force_pio_avail_update(pd->port_dd);
 		break;
 	case IPATH_CMD_POLL_TYPE:
 		pd->poll_type = cmd.cmd.poll_type;

drivers/infiniband/hw/ipath/ipath_init_chip.c

@@ -521,7 +521,9 @@ static void enable_chip(struct ipath_devdata *dd,
 			pioavail = dd->ipath_pioavailregs_dma[i ^ 1];
 		else
 			pioavail = dd->ipath_pioavailregs_dma[i];
-		dd->ipath_pioavailshadow[i] = le64_to_cpu(pioavail);
+		dd->ipath_pioavailshadow[i] = le64_to_cpu(pioavail) |
+			(~dd->ipath_pioavailkernel[i] <<
+			INFINIPATH_SENDPIOAVAIL_BUSY_SHIFT);
 	}
 	/* can get counters, stats, etc. */
 	dd->ipath_flags |= IPATH_PRESENT;
@@ -743,7 +745,9 @@ int ipath_init_chip(struct ipath_devdata *dd, int reinit)
 		ipath_dbg("%u pbufs/port leaves %u unused, add to kernel\n",
 			  dd->ipath_pbufsport, val32);
 	}
-	dd->ipath_lastpioindex = dd->ipath_lastport_piobuf;
+	dd->ipath_lastpioindex = 0;
+	dd->ipath_lastpioindexl = dd->ipath_piobcnt2k;
+	ipath_chg_pioavailkernel(dd, 0, piobufs, 1);
 	ipath_cdbg(VERBOSE, "%d PIO bufs for kernel out of %d total %u "
 		   "each for %u user ports\n", kpiobufs,
 		   piobufs, dd->ipath_pbufsport, uports);

drivers/infiniband/hw/ipath/ipath_intr.c

@@ -804,7 +804,6 @@ void ipath_clear_freeze(struct ipath_devdata *dd)
 {
 	int i, im;
 	u64 val;
-	unsigned long flags;
 
 	/* disable error interrupts, to avoid confusion */
 	ipath_write_kreg(dd, dd->ipath_kregs->kr_errormask, 0ULL);
@@ -823,14 +822,7 @@ void ipath_clear_freeze(struct ipath_devdata *dd)
 			 dd->ipath_control);
 
 	/* ensure pio avail updates continue */
-	spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags);
-	ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
-		 dd->ipath_sendctrl & ~INFINIPATH_S_PIOBUFAVAILUPD);
-	ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
-	ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
-			 dd->ipath_sendctrl);
-	ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
-	spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags);
+	ipath_force_pio_avail_update(dd);
 
 	/*
 	 * We just enabled pioavailupdate, so dma copy is almost certainly
@@ -842,7 +834,9 @@ void ipath_clear_freeze(struct ipath_devdata *dd)
 			i ^ 1 : i;
 		val = ipath_read_kreg64(dd, (0x1000 / sizeof(u64)) + im);
 		dd->ipath_pioavailregs_dma[i] = cpu_to_le64(val);
-		dd->ipath_pioavailshadow[i] = val;
+		dd->ipath_pioavailshadow[i] = val |
+			(~dd->ipath_pioavailkernel[i] <<
+			INFINIPATH_SENDPIOAVAIL_BUSY_SHIFT);
 	}
 
 	/*

drivers/infiniband/hw/ipath/ipath_kernel.h

@@ -191,6 +191,9 @@ struct ipath_skbinfo {
 	dma_addr_t phys;
 };
 
+/* max dwords in small buffer packet */
+#define IPATH_SMALLBUF_DWORDS (dd->ipath_piosize2k >> 2)
+
 /*
  * Possible IB config parameters for ipath_f_get/set_ib_cfg()
  */
@@ -366,6 +369,7 @@ struct ipath_devdata {
 	 * get to multiple devices
 	 */
 	u32 ipath_lastpioindex;
+	u32 ipath_lastpioindexl;
 	/* max length of freezemsg */
 	u32 ipath_freezelen;
 	/*
@@ -453,6 +457,8 @@ struct ipath_devdata {
 	 * init time.
 	 */
 	unsigned long ipath_pioavailshadow[8];
+	/* bitmap of send buffers available for the kernel to use with PIO. */
+	unsigned long ipath_pioavailkernel[8];
 	/* shadow of kr_gpio_out, for rmw ops */
 	u64 ipath_gpio_out;
 	/* shadow the gpio mask register */
@@ -869,13 +875,16 @@ void ipath_hol_event(unsigned long);
 
 /* free up any allocated data at closes */
 void ipath_free_data(struct ipath_portdata *dd);
-u32 __iomem *ipath_getpiobuf(struct ipath_devdata *, u32 *);
+u32 __iomem *ipath_getpiobuf(struct ipath_devdata *, u32, u32 *);
+void ipath_chg_pioavailkernel(struct ipath_devdata *dd, unsigned start,
+				unsigned len, int avail);
 void ipath_init_iba6120_funcs(struct ipath_devdata *);
 void ipath_init_iba6110_funcs(struct ipath_devdata *);
 void ipath_get_eeprom_info(struct ipath_devdata *);
 int ipath_update_eeprom_log(struct ipath_devdata *dd);
 void ipath_inc_eeprom_err(struct ipath_devdata *dd, u32 eidx, u32 incr);
 u64 ipath_snap_cntr(struct ipath_devdata *, ipath_creg);
+void ipath_force_pio_avail_update(struct ipath_devdata *);
 void signal_ib_event(struct ipath_devdata *dd, enum ib_event_type ev);
 
 /*

drivers/infiniband/hw/ipath/ipath_registers.h

@@ -66,6 +66,8 @@
 
 /* kr_sendctrl bits */
 #define INFINIPATH_S_DISARMPIOBUF_SHIFT 16
+#define INFINIPATH_S_UPDTHRESH_SHIFT 24
+#define INFINIPATH_S_UPDTHRESH_MASK 0x1f
 
 #define IPATH_S_ABORT		0
 #define IPATH_S_PIOINTBUFAVAIL	1

drivers/infiniband/hw/ipath/ipath_verbs.c

@@ -875,7 +875,7 @@ static int ipath_verbs_send_pio(struct ipath_qp *qp, u32 *hdr, u32 hdrwords,
 	unsigned flush_wc;
 	int ret;
 
-	piobuf = ipath_getpiobuf(dd, NULL);
+	piobuf = ipath_getpiobuf(dd, plen, NULL);
 	if (unlikely(piobuf == NULL)) {
 		ret = -EBUSY;
 		goto bail;