[PATCH] s390 (8/10): console device drivers.

From: Martin Schwidefsky (schwidefsky@de.ibm.com)
Date: Mon May 26 2003 - 12:40:33 EST

s390 console driver fixes:
- Register console ttys via module_init. Remove sclp_tty_init and
tty3215_init from tty_io.c
- con3215: use set_current_state.
- sclp: Fix race condition in sclp interrupt handler. Fix deadlock on
sclp_conbuf_lock for certain error conditions.

diffstat:
drivers/char/tty_io.c | 5 ---
drivers/s390/char/con3215.c | 4 +--
drivers/s390/char/sclp.c | 42 +++++++++++++++++++++------------
drivers/s390/char/sclp_con.c | 54 ++++++++++++++++++++++++-------------------
drivers/s390/char/sclp_tty.c | 25 +++++++++++--------
drivers/s390/char/sclp_tty.h | 4 +++
6 files changed, 79 insertions(+), 55 deletions(-)

diff -urN linux-2.5/drivers/char/tty_io.c linux-2.5-s390/drivers/char/tty_io.c
--- linux-2.5/drivers/char/tty_io.c Mon May 26 19:20:26 2003
+++ linux-2.5-s390/drivers/char/tty_io.c Mon May 26 19:20:47 2003
@@ -145,8 +145,6 @@
extern int vme_scc_init (void);
extern int serial167_init(void);
extern int rs_8xx_init(void);
-extern void sclp_tty_init(void);
-extern void tty3215_init(void);
extern void tub3270_init(void);
extern void rs_360_init(void);
extern void tx3912_rs_init(void);
@@ -2480,9 +2478,6 @@
#ifdef CONFIG_TN3270
tub3270_init();
#endif
-#ifdef CONFIG_SCLP_TTY
- sclp_tty_init();
-#endif
#ifdef CONFIG_A2232
a2232board_init();
#endif
diff -urN linux-2.5/drivers/s390/char/con3215.c linux-2.5-s390/drivers/s390/char/con3215.c
--- linux-2.5/drivers/s390/char/con3215.c Mon May 5 01:53:35 2003
+++ linux-2.5-s390/drivers/s390/char/con3215.c Mon May 26 19:20:47 2003
@@ -697,12 +697,12 @@
raw->queued_read != NULL) {
raw->flags |= RAW3215_CLOSING;
add_wait_queue(&raw->empty_wait, &wait);
- current->state = TASK_INTERRUPTIBLE;
+ set_current_state(TASK_INTERRUPTIBLE);
spin_unlock_irqrestore(raw->lock, flags);
schedule();
spin_lock_irqsave(raw->lock, flags);
remove_wait_queue(&raw->empty_wait, &wait);
- current->state = TASK_RUNNING;
+ set_current_state(TASK_RUNNING);
raw->flags &= ~(RAW3215_ACTIVE | RAW3215_CLOSING);
}
spin_unlock_irqrestore(raw->lock, flags);
diff -urN linux-2.5/drivers/s390/char/sclp.c linux-2.5-s390/drivers/s390/char/sclp.c
--- linux-2.5/drivers/s390/char/sclp.c Mon May 5 01:53:32 2003
+++ linux-2.5-s390/drivers/s390/char/sclp.c Mon May 26 19:20:47 2003
@@ -18,7 +18,9 @@
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/timer.h>
+#include <linux/init.h>
#include <asm/s390_ext.h>
+#include <asm/processor.h>

#include "sclp.h"

@@ -49,7 +51,7 @@
/* Timer for init mask retries. */
static struct timer_list retry_timer;

-static unsigned long sclp_status = 0;
+static volatile unsigned long sclp_status = 0;
/* some status flags */
#define SCLP_INIT 0
#define SCLP_RUNNING 1
@@ -275,20 +277,24 @@
struct list_head *l;
struct sclp_req *req, *tmp;

+ spin_lock(&sclp_lock);
/*
* Only process interrupt if sclp is initialized.
* This avoids strange effects for a pending request
* from before the last re-ipl.
*/
- if (!test_bit(SCLP_INIT, &sclp_status))
+ if (!test_bit(SCLP_INIT, &sclp_status)) {
+ /* Now clear the running bit */
+ clear_bit(SCLP_RUNNING, &sclp_status);
+ spin_unlock(&sclp_lock);
return;
+ }
ext_int_param = S390_lowcore.ext_params;
finished_sccb = ext_int_param & EXT_INT_SCCB_MASK;
evbuf_pending = ext_int_param & (EXT_INT_EVBUF_PENDING |
EXT_INT_STATECHANGE_PENDING);
irq_enter();
req = NULL;
- spin_lock(&sclp_lock);
if (finished_sccb != 0U) {
list_for_each(l, &sclp_req_queue) {
tmp = list_entry(l, struct sclp_req, list);
@@ -299,9 +305,6 @@
}
}
}
- /* Head queue a read sccb if an event buffer is pending */
- if (evbuf_pending)
- __sclp_unconditional_read();
spin_unlock(&sclp_lock);
/* Perform callback */
if (req != NULL) {
@@ -309,8 +312,13 @@
if (req->callback != NULL)
req->callback(req, req->callback_data);
}
+ spin_lock(&sclp_lock);
+ /* Head queue a read sccb if an event buffer is pending */
+ if (evbuf_pending)
+ __sclp_unconditional_read();
/* Now clear the running bit */
clear_bit(SCLP_RUNNING, &sclp_status);
+ spin_unlock(&sclp_lock);
/* and start next request on the queue */
sclp_start_request();
irq_exit();
@@ -344,8 +352,10 @@
: "=m" (psw_mask) : "a" (&psw_mask) : "memory");

/* wait until ISR signals receipt of interrupt */
- while (test_bit(SCLP_RUNNING, &sclp_status))
+ while (test_bit(SCLP_RUNNING, &sclp_status)) {
barrier();
+ cpu_relax();
+ }

/* disable external interruptions */
asm volatile ("SSM 0(%0)"
@@ -631,6 +641,14 @@
/* Already initialized. */
return 0;

+ spin_lock_init(&sclp_lock);
+ INIT_LIST_HEAD(&sclp_req_queue);
+
+ /* init event list */
+ INIT_LIST_HEAD(&sclp_reg_list);
+ list_add(&sclp_state_change_event.list, &sclp_reg_list);
+ list_add(&sclp_quiesce_event.list, &sclp_reg_list);
+
/*
* request the 0x2401 external interrupt
* The sclp driver is initialized early (before kmalloc works). We
@@ -640,14 +658,6 @@
&ext_int_info_hwc) != 0)
return -EBUSY;

- spin_lock_init(&sclp_lock);
- INIT_LIST_HEAD(&sclp_req_queue);
-
- /* init event list */
- INIT_LIST_HEAD(&sclp_reg_list);
- list_add(&sclp_state_change_event.list, &sclp_reg_list);
- list_add(&sclp_quiesce_event.list, &sclp_reg_list);
-
/* enable service-signal external interruptions,
* Control Register 0 bit 22 := 1
* (besides PSW bit 7 must be set to 1 sometimes for external
@@ -762,6 +772,8 @@
return unprocessed;
}

+module_init(sclp_init);
+
EXPORT_SYMBOL(sclp_add_request);
EXPORT_SYMBOL(sclp_sync_wait);
EXPORT_SYMBOL(sclp_register);
diff -urN linux-2.5/drivers/s390/char/sclp_con.c linux-2.5-s390/drivers/s390/char/sclp_con.c
--- linux-2.5/drivers/s390/char/sclp_con.c Mon May 5 01:53:29 2003
+++ linux-2.5-s390/drivers/s390/char/sclp_con.c Mon May 26 19:20:47 2003
@@ -15,9 +15,11 @@
#include <linux/timer.h>
#include <linux/jiffies.h>
#include <linux/bootmem.h>
+#include <linux/err.h>

#include "sclp.h"
#include "sclp_rw.h"
+#include "sclp_tty.h"

#define SCLP_CON_PRINT_HEADER "sclp console driver: "

@@ -69,10 +71,23 @@
}

static inline void
-__sclp_conbuf_emit(struct sclp_buffer *buffer)
+sclp_conbuf_emit(void)
{
+ struct sclp_buffer* buffer;
+ unsigned long flags;
+ int count;
+
+ spin_lock_irqsave(&sclp_con_lock, flags);
+ buffer = sclp_conbuf;
+ sclp_conbuf = NULL;
+ if (buffer == NULL) {
+ spin_unlock_irqrestore(&sclp_con_lock, flags);
+ return;
+ }
list_add_tail(&buffer->list, &sclp_con_outqueue);
- if (sclp_con_buffer_count++ == 0)
+ count = sclp_con_buffer_count++;
+ spin_unlock_irqrestore(&sclp_con_lock, flags);
+ if (count == 0)
sclp_emit_buffer(buffer, sclp_conbuf_callback);
}

@@ -83,14 +98,7 @@
static void
sclp_console_timeout(unsigned long data)
{
- unsigned long flags;
-
- spin_lock_irqsave(&sclp_con_lock, flags);
- if (sclp_conbuf != NULL) {
- __sclp_conbuf_emit(sclp_conbuf);
- sclp_conbuf = NULL;
- }
- spin_unlock_irqrestore(&sclp_con_lock, flags);
+ sclp_conbuf_emit();
}

/*
@@ -134,8 +142,9 @@
* output buffer. Emit the buffer, create a new buffer
* and then output the rest of the string.
*/
- __sclp_conbuf_emit(sclp_conbuf);
- sclp_conbuf = NULL;
+ spin_unlock_irqrestore(&sclp_con_lock, flags);
+ sclp_conbuf_emit();
+ spin_lock_irqsave(&sclp_con_lock, flags);
message += written;
count -= written;
} while (count > 0);
@@ -150,11 +159,11 @@
spin_unlock_irqrestore(&sclp_con_lock, flags);
}

-/* returns the device number of the SCLP console */
-static kdev_t
-sclp_console_device(struct console *c)
+static struct tty_driver *
+sclp_console_device(struct console *c, int *index)
{
- return mk_kdev(sclp_console_major, sclp_console_minor);
+ *index = c->index;
+ return &sclp_tty_driver;
}

/*
@@ -167,13 +176,10 @@
{
unsigned long flags;

+ sclp_conbuf_emit();
spin_lock_irqsave(&sclp_con_lock, flags);
if (timer_pending(&sclp_con_timer))
del_timer(&sclp_con_timer);
- if (sclp_conbuf != NULL) {
- __sclp_conbuf_emit(sclp_conbuf);
- sclp_conbuf = NULL;
- }
while (sclp_con_buffer_count > 0) {
spin_unlock_irqrestore(&sclp_con_lock, flags);
sclp_sync_wait();
@@ -204,17 +210,19 @@
{
void *page;
int i;
+ int rc;

if (!CONSOLE_IS_SCLP)
return 0;
- if (sclp_rw_init() != 0)
- return 0;
+ rc = sclp_rw_init();
+ if (rc)
+ return rc;
/* Allocate pages for output buffering */
INIT_LIST_HEAD(&sclp_con_pages);
for (i = 0; i < MAX_CONSOLE_PAGES; i++) {
page = alloc_bootmem_low_pages(PAGE_SIZE);
if (page == NULL)
- return 0;
+ return -ENOMEM;
list_add_tail((struct list_head *) page, &sclp_con_pages);
}
INIT_LIST_HEAD(&sclp_con_outqueue);
diff -urN linux-2.5/drivers/s390/char/sclp_tty.c linux-2.5-s390/drivers/s390/char/sclp_tty.c
--- linux-2.5/drivers/s390/char/sclp_tty.c Mon May 5 01:53:02 2003
+++ linux-2.5-s390/drivers/s390/char/sclp_tty.c Mon May 26 19:20:47 2003
@@ -16,6 +16,8 @@
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/init.h>
#include <asm/uaccess.h>

#include "ctrlchar.h"
@@ -55,7 +57,7 @@
static unsigned char sclp_tty_chars[SCLP_TTY_BUF_SIZE];
static unsigned short int sclp_tty_chars_count;

-static struct tty_driver sclp_tty_driver;
+struct tty_driver sclp_tty_driver;
static struct tty_struct * sclp_tty_table[1];
static struct termios * sclp_tty_termios[1];
static struct termios * sclp_tty_termios_locked[1];
@@ -710,7 +712,7 @@
.receiver_fn = sclp_tty_receiver
};

-void
+int __init
sclp_tty_init(void)
{
void *page;
@@ -718,20 +720,20 @@
int rc;

if (!CONSOLE_IS_SCLP)
- return;
+ return 0;
rc = sclp_rw_init();
- if (rc != 0) {
+ if (rc) {
printk(KERN_ERR SCLP_TTY_PRINT_HEADER
"could not register tty - "
"sclp_rw_init returned %d\n", rc);
- return;
+ return rc;
}
/* Allocate pages for output buffering */
INIT_LIST_HEAD(&sclp_tty_pages);
for (i = 0; i < MAX_KMEM_PAGES; i++) {
page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
if (page == NULL)
- return;
+ return -ENOMEM;
list_add_tail((struct list_head *) page, &sclp_tty_pages);
}
INIT_LIST_HEAD(&sclp_tty_outqueue);
@@ -753,8 +755,9 @@
sclp_tty_chars_count = 0;
sclp_tty = NULL;

- if (sclp_register(&sclp_input_event) != 0)
- return;
+ rc = sclp_register(&sclp_input_event);
+ if (rc)
+ return rc;

memset (&sclp_tty_driver, 0, sizeof(struct tty_driver));
sclp_tty_driver.magic = TTY_DRIVER_MAGIC;
@@ -810,8 +813,10 @@
sclp_tty_driver.write_proc = NULL;

rc = tty_register_driver(&sclp_tty_driver);
- if (rc != 0)
+ if (rc)
printk(KERN_ERR SCLP_TTY_PRINT_HEADER
"could not register tty - "
- "sclp_drv_register returned %d\n", rc);
+ "tty_register_driver returned %d\n", rc);
+ return rc;
}
+module_init(sclp_tty_init);
diff -urN linux-2.5/drivers/s390/char/sclp_tty.h linux-2.5-s390/drivers/s390/char/sclp_tty.h
--- linux-2.5/drivers/s390/char/sclp_tty.h Mon May 5 01:53:31 2003
+++ linux-2.5-s390/drivers/s390/char/sclp_tty.h Mon May 26 19:20:47 2003
@@ -12,6 +12,8 @@
#define __SCLP_TTY_H__

#include <linux/ioctl.h>
+#include <linux/termios.h>
+#include <linux/tty_driver.h>

/* This is the type of data structures storing sclp ioctl setting. */
struct sclp_ioctls {
@@ -64,4 +66,6 @@
/* get the number of buffers/pages got from kernel at startup */
#define TIOCSCLPGKBUF _IOR(SCLP_IOCTL_LETTER, 20, unsigned short)

+extern struct tty_driver sclp_tty_driver;
+
#endif /* __SCLP_TTY_H__ */
-
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