s390: remove superfluous tpi from wait_cons_dev

wait_cons_dev waits for a particular subchannel to complete an I/O.
It is not necessary to use tpi to get the subchannel id as it is
already known. This avoids changes to the interrupt subclass mask
and allows to remove the lock & unlock of the subchannel lock.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 19 insertions, 54 deletions

diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c
index a49c46c91983..a6ddaed8793d 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -656,51 +656,34 @@ static struct io_subchannel_private console_priv;
 static int console_subchannel_in_use;
 
 /*
- * Use cio_tpi to get a pending interrupt and call the interrupt handler.
- * Return non-zero if an interrupt was processed, zero otherwise.
+ * Use cio_tsch to update the subchannel status and call the interrupt handler
+ * if status had been pending. Called with the console_subchannel lock.
  */
-static int cio_tpi(void)
+static void cio_tsch(struct subchannel *sch)
 {
-        struct tpi_info *tpi_info;
-        struct subchannel *sch;
         struct irb *irb;
         int irq_context;
 
-        tpi_info = (struct tpi_info *)&S390_lowcore.subchannel_id;
-        if (tpi(NULL) != 1)
-                return 0;
-        kstat_cpu(smp_processor_id()).irqs[IO_INTERRUPT]++;
-        if (tpi_info->adapter_IO) {
-                do_adapter_IO(tpi_info->isc);
-                return 1;
-        }
         irb = (struct irb *)&S390_lowcore.irb;
         /* Store interrupt response block to lowcore. */
-        if (tsch(tpi_info->schid, irb) != 0) {
+        if (tsch(sch->schid, irb) != 0)
                 /* Not status pending or not operational. */
-                kstat_cpu(smp_processor_id()).irqs[IOINT_CIO]++;
-                return 1;
-        }
-        sch = (struct subchannel *)(unsigned long)tpi_info->intparm;
-        if (!sch) {
-                kstat_cpu(smp_processor_id()).irqs[IOINT_CIO]++;
-                return 1;
-        }
+                return;
+        memcpy(&sch->schib.scsw, &irb->scsw, sizeof(union scsw));
+        /* Call interrupt handler with updated status. */
         irq_context = in_interrupt();
-        if (!irq_context)
+        if (!irq_context) {
                 local_bh_disable();
-        irq_enter();
-        spin_lock(sch->lock);
-        memcpy(&sch->schib.scsw, &irb->scsw, sizeof(union scsw));
+                irq_enter();
+        }
         if (sch->driver && sch->driver->irq)
                 sch->driver->irq(sch);
         else
                 kstat_cpu(smp_processor_id()).irqs[IOINT_CIO]++;
-        spin_unlock(sch->lock);
-        irq_exit();
-        if (!irq_context)
+        if (!irq_context) {
+                irq_exit();
                 _local_bh_enable();
-        return 1;
+        }
 }
 
 void *cio_get_console_priv(void)
@@ -712,34 +695,16 @@ void *cio_get_console_priv(void)
  * busy wait for the next interrupt on the console
  */
 void wait_cons_dev(void)
-        __releases(console_subchannel.lock)
-        __acquires(console_subchannel.lock)
 {
-        unsigned long cr6      __attribute__ ((aligned (8)));
-        unsigned long save_cr6 __attribute__ ((aligned (8)));
-
-        /* 
-         * before entering the spinlock we may already have
-         * processed the interrupt on a different CPU...
-         */
         if (!console_subchannel_in_use)
                 return;
 
-        /* disable all but the console isc */
-        __ctl_store (save_cr6, 6, 6);
-        cr6 = 1UL << (31 - CONSOLE_ISC);
-        __ctl_load (cr6, 6, 6);
-
-        do {
-                spin_unlock(console_subchannel.lock);
-                if (!cio_tpi())
-                        cpu_relax();
-                spin_lock(console_subchannel.lock);
-        } while (console_subchannel.schib.scsw.cmd.actl != 0);
-        /*
-         * restore previous isc value
-         */
-        __ctl_load (save_cr6, 6, 6);
+        while (1) {
+                cio_tsch(&console_subchannel);
+                if (console_subchannel.schib.scsw.cmd.actl == 0)
+                        break;
+                udelay_simple(100);
+        }
 }
 
 static int