[patch 12/38] cio: fix subchannel channel-path data usage

From: Martin Schwidefsky
Date: Fri Apr 27 2007 - 10:19:44 EST

From: Peter Oberparleiter <peter.oberparleiter@xxxxxxxxxx>

Ensure that channel-path related subchannel data is only retrieved and
used when it is valid and that it is updated when it may have changed.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
---

drivers/s390/cio/chsc.c | 303 ++++++++++++++----------------------------
drivers/s390/cio/chsc.h | 10 +
drivers/s390/cio/cio.h | 16 --
drivers/s390/cio/css.c | 53 ++++++-
drivers/s390/cio/css.h | 1
drivers/s390/cio/device.c | 12 +
drivers/s390/cio/device_fsm.c | 1
7 files changed, 179 insertions(+), 217 deletions(-)

Index: quilt-2.6/drivers/s390/cio/chsc.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/chsc.c 2007-04-27 16:04:54.000000000 +0200
+++ quilt-2.6/drivers/s390/cio/chsc.c 2007-04-27 16:04:55.000000000 +0200
@@ -26,155 +26,84 @@

static void *sei_page;

-/* FIXME: this is _always_ called for every subchannel. shouldn't we
- * process more than one at a time? */
-static int
-chsc_get_sch_desc_irq(struct subchannel *sch, void *page)
-{
- int ccode, j;
-
- struct {
- struct chsc_header request;
- u16 reserved1a:10;
- u16 ssid:2;
- u16 reserved1b:4;
- u16 f_sch; /* first subchannel */
- u16 reserved2;
- u16 l_sch; /* last subchannel */
- u32 reserved3;
- struct chsc_header response;
- u32 reserved4;
- u8 sch_valid : 1;
- u8 dev_valid : 1;
- u8 st : 3; /* subchannel type */
- u8 zeroes : 3;
- u8 unit_addr; /* unit address */
- u16 devno; /* device number */
- u8 path_mask;
- u8 fla_valid_mask;
- u16 sch; /* subchannel */
- u8 chpid[8]; /* chpids 0-7 */
- u16 fla[8]; /* full link addresses 0-7 */
- } __attribute__ ((packed)) *ssd_area;
+struct chsc_ssd_area {
+ struct chsc_header request;
+ u16 :10;
+ u16 ssid:2;
+ u16 :4;
+ u16 f_sch; /* first subchannel */
+ u16 :16;
+ u16 l_sch; /* last subchannel */
+ u32 :32;
+ struct chsc_header response;
+ u32 :32;
+ u8 sch_valid : 1;
+ u8 dev_valid : 1;
+ u8 st : 3; /* subchannel type */
+ u8 zeroes : 3;
+ u8 unit_addr; /* unit address */
+ u16 devno; /* device number */
+ u8 path_mask;
+ u8 fla_valid_mask;
+ u16 sch; /* subchannel */
+ u8 chpid[8]; /* chpids 0-7 */
+ u16 fla[8]; /* full link addresses 0-7 */
+} __attribute__ ((packed));

- ssd_area = page;
+int chsc_get_ssd_info(struct subchannel_id schid, struct chsc_ssd_info *ssd)
+{
+ unsigned long page;
+ struct chsc_ssd_area *ssd_area;
+ int ccode;
+ int ret;
+ int i;
+ int mask;

+ page = get_zeroed_page(GFP_KERNEL | GFP_DMA);
+ if (!page)
+ return -ENOMEM;
+ ssd_area = (struct chsc_ssd_area *) page;
ssd_area->request.length = 0x0010;
ssd_area->request.code = 0x0004;
-
- ssd_area->ssid = sch->schid.ssid;
- ssd_area->f_sch = sch->schid.sch_no;
- ssd_area->l_sch = sch->schid.sch_no;
+ ssd_area->ssid = schid.ssid;
+ ssd_area->f_sch = schid.sch_no;
+ ssd_area->l_sch = schid.sch_no;

ccode = chsc(ssd_area);
+ /* Check response. */
if (ccode > 0) {
- pr_debug("chsc returned with ccode = %d\n", ccode);
- return (ccode == 3) ? -ENODEV : -EBUSY;
+ ret = (ccode == 3) ? -ENODEV : -EBUSY;
+ goto out_free;
}
-
- switch (ssd_area->response.code) {
- case 0x0001: /* everything ok */
- break;
- case 0x0002:
- CIO_CRW_EVENT(2, "Invalid command!\n");
- return -EINVAL;
- case 0x0003:
- CIO_CRW_EVENT(2, "Error in chsc request block!\n");
- return -EINVAL;
- case 0x0004:
- CIO_CRW_EVENT(2, "Model does not provide ssd\n");
- return -EOPNOTSUPP;
- default:
- CIO_CRW_EVENT(2, "Unknown CHSC response %d\n",
+ if (ssd_area->response.code != 0x0001) {
+ CIO_MSG_EVENT(2, "chsc: ssd failed for 0.%x.%04x (rc=%04x)\n",
+ schid.ssid, schid.sch_no,
ssd_area->response.code);
- return -EIO;
+ ret = -EIO;
+ goto out_free;
}
-
- /*
- * ssd_area->st stores the type of the detected
- * subchannel, with the following definitions:
- *
- * 0: I/O subchannel: All fields have meaning
- * 1: CHSC subchannel: Only sch_val, st and sch
- * have meaning
- * 2: Message subchannel: All fields except unit_addr
- * have meaning
- * 3: ADM subchannel: Only sch_val, st and sch
- * have meaning
- *
- * Other types are currently undefined.
- */
- if (ssd_area->st > 3) { /* uhm, that looks strange... */
- CIO_CRW_EVENT(0, "Strange subchannel type %d"
- " for sch 0.%x.%04x\n", ssd_area->st,
- sch->schid.ssid, sch->schid.sch_no);
- /*
- * There may have been a new subchannel type defined in the
- * time since this code was written; since we don't know which
- * fields have meaning and what to do with it we just jump out
- */
- return 0;
- } else {
- const char *type[4] = {"I/O", "chsc", "message", "ADM"};
- CIO_CRW_EVENT(6, "ssd: sch 0.%x.%04x is %s subchannel\n",
- sch->schid.ssid, sch->schid.sch_no,
- type[ssd_area->st]);
-
- sch->ssd_info.valid = 1;
- sch->ssd_info.type = ssd_area->st;
- }
-
- if (ssd_area->st == 0 || ssd_area->st == 2) {
- for (j = 0; j < 8; j++) {
- if (!((0x80 >> j) & ssd_area->path_mask &
- ssd_area->fla_valid_mask))
- continue;
- sch->ssd_info.chpid[j] = ssd_area->chpid[j];
- sch->ssd_info.fla[j] = ssd_area->fla[j];
- }
+ if (!ssd_area->sch_valid) {
+ ret = -ENODEV;
+ goto out_free;
}
- return 0;
-}
-
-int
-css_get_ssd_info(struct subchannel *sch)
-{
- int ret;
- void *page;
-
- page = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
- if (!page)
- return -ENOMEM;
- spin_lock_irq(sch->lock);
- ret = chsc_get_sch_desc_irq(sch, page);
- if (ret) {
- static int cio_chsc_err_msg;
-
- if (!cio_chsc_err_msg) {
- printk(KERN_ERR
- "chsc_get_sch_descriptions:"
- " Error %d while doing chsc; "
- "processing some machine checks may "
- "not work\n", ret);
- cio_chsc_err_msg = 1;
- }
- }
- spin_unlock_irq(sch->lock);
- free_page((unsigned long)page);
- if (!ret) {
- int j, mask;
- struct chp_id chpid;
-
- chp_id_init(&chpid);
- /* Allocate channel path structures, if needed. */
- for (j = 0; j < 8; j++) {
- mask = 0x80 >> j;
- chpid.id = sch->ssd_info.chpid[j];
- if ((sch->schib.pmcw.pim & mask) &&
- !chp_is_registered(chpid))
- chp_new(chpid);
+ /* Copy data */
+ ret = 0;
+ memset(ssd, 0, sizeof(struct chsc_ssd_info));
+ if ((ssd_area->st != 0) && (ssd_area->st != 2))
+ goto out_free;
+ ssd->path_mask = ssd_area->path_mask;
+ ssd->fla_valid_mask = ssd_area->fla_valid_mask;
+ for (i = 0; i < 8; i++) {
+ mask = 0x80 >> i;
+ if (ssd_area->path_mask & mask) {
+ chp_id_init(&ssd->chpid[i]);
+ ssd->chpid[i].id = ssd_area->chpid[i];
}
+ if (ssd_area->fla_valid_mask & mask)
+ ssd->fla[i] = ssd_area->fla[i];
}
+out_free:
+ free_page(page);
return ret;
}

@@ -276,47 +205,6 @@
s390_subchannel_remove_chpid);
}

-struct res_acc_data {
- struct chp_id chpid;
- u32 fla_mask;
- u16 fla;
-};
-
-static int s390_process_res_acc_sch(struct res_acc_data *res_data,
- struct subchannel *sch)
-{
- int found;
- int chp;
- int ccode;
-
- found = 0;
- for (chp = 0; chp <= 7; chp++)
- /*
- * check if chpid is in information updated by ssd
- */
- if (sch->ssd_info.valid &&
- sch->ssd_info.chpid[chp] == res_data->chpid.id &&
- (sch->ssd_info.fla[chp] & res_data->fla_mask)
- == res_data->fla) {
- found = 1;
- break;
- }
-
- if (found == 0)
- return 0;
-
- /*
- * Do a stsch to update our subchannel structure with the
- * new path information and eventually check for logically
- * offline chpids.
- */
- ccode = stsch(sch->schid, &sch->schib);
- if (ccode > 0)
- return 0;
-
- return 0x80 >> chp;
-}
-
static int
s390_process_res_acc_new_sch(struct subchannel_id schid)
{
@@ -338,6 +226,32 @@
return 0;
}

+struct res_acc_data {
+ struct chp_id chpid;
+ u32 fla_mask;
+ u16 fla;
+};
+
+static int get_res_chpid_mask(struct chsc_ssd_info *ssd,
+ struct res_acc_data *data)
+{
+ int i;
+ int mask;
+
+ for (i = 0; i < 8; i++) {
+ mask = 0x80 >> i;
+ if (!(ssd->path_mask & mask))
+ continue;
+ if (!chp_id_is_equal(&ssd->chpid[i], &data->chpid))
+ continue;
+ if ((ssd->fla_valid_mask & mask) &&
+ ((ssd->fla[i] & data->fla_mask) != data->fla))
+ continue;
+ return mask;
+ }
+ return 0;
+}
+
static int
__s390_process_res_acc(struct subchannel_id schid, void *data)
{
@@ -352,14 +266,11 @@
return s390_process_res_acc_new_sch(schid);

spin_lock_irq(sch->lock);
-
- chp_mask = s390_process_res_acc_sch(res_data, sch);
-
- if (chp_mask == 0) {
- spin_unlock_irq(sch->lock);
- put_device(&sch->dev);
- return 0;
- }
+ chp_mask = get_res_chpid_mask(&sch->ssd_info, res_data);
+ if (chp_mask == 0)
+ goto out;
+ if (stsch(sch->schid, &sch->schib))
+ goto out;
old_lpm = sch->lpm;
sch->lpm = ((sch->schib.pmcw.pim &
sch->schib.pmcw.pam &
@@ -369,13 +280,12 @@
device_trigger_reprobe(sch);
else if (sch->driver && sch->driver->verify)
sch->driver->verify(&sch->dev);
-
+out:
spin_unlock_irq(sch->lock);
put_device(&sch->dev);
return 0;
}

-
static void s390_process_res_acc (struct res_acc_data *res_data)
{
char dbf_txt[15];
@@ -661,29 +571,30 @@
struct chp_id chpid, int on)
{
int chp, old_lpm;
+ int mask;
unsigned long flags;

- if (!sch->ssd_info.valid)
- return;
-
spin_lock_irqsave(sch->lock, flags);
old_lpm = sch->lpm;
for (chp = 0; chp < 8; chp++) {
- if (sch->ssd_info.chpid[chp] != chpid.id)
+ mask = 0x80 >> chp;
+ if (!(sch->ssd_info.path_mask & mask))
+ continue;
+ if (!chp_id_is_equal(&sch->ssd_info.chpid[chp], &chpid))
continue;

if (on) {
- sch->opm |= (0x80 >> chp);
- sch->lpm |= (0x80 >> chp);
+ sch->opm |= mask;
+ sch->lpm |= mask;
if (!old_lpm)
device_trigger_reprobe(sch);
else if (sch->driver && sch->driver->verify)
sch->driver->verify(&sch->dev);
break;
}
- sch->opm &= ~(0x80 >> chp);
- sch->lpm &= ~(0x80 >> chp);
- if (check_for_io_on_path(sch, (0x80 >> chp))) {
+ sch->opm &= ~mask;
+ sch->lpm &= ~mask;
+ if (check_for_io_on_path(sch, mask)) {
if (device_is_online(sch))
/* Path verification is done after killing. */
device_kill_io(sch);
Index: quilt-2.6/drivers/s390/cio/chsc.h
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/chsc.h 2007-04-27 16:04:54.000000000 +0200
+++ quilt-2.6/drivers/s390/cio/chsc.h 2007-04-27 16:04:55.000000000 +0200
@@ -4,6 +4,7 @@
#include <linux/types.h>
#include <linux/device.h>
#include <asm/chpid.h>
+#include "schid.h"

#define CHSC_SDA_OC_MSS 0x2

@@ -35,7 +36,6 @@

struct channel_path;

-extern int css_get_ssd_info(struct subchannel *);
extern void chsc_process_crw(void);

struct css_general_char {
@@ -69,6 +69,14 @@
extern struct css_general_char css_general_characteristics;
extern struct css_chsc_char css_chsc_characteristics;

+struct chsc_ssd_info {
+ u8 path_mask;
+ u8 fla_valid_mask;
+ struct chp_id chpid[8];
+ u16 fla[8];
+};
+extern int chsc_get_ssd_info(struct subchannel_id schid,
+ struct chsc_ssd_info *ssd);
extern int chsc_determine_css_characteristics(void);
extern int css_characteristics_avail;

Index: quilt-2.6/drivers/s390/cio/cio.h
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/cio.h 2007-04-27 16:04:54.000000000 +0200
+++ quilt-2.6/drivers/s390/cio/cio.h 2007-04-27 16:04:55.000000000 +0200
@@ -1,19 +1,11 @@
#ifndef S390_CIO_H
#define S390_CIO_H

-#include "schid.h"
#include <linux/mutex.h>
#include <linux/device.h>
-
-/*
- * where we put the ssd info
- */
-struct ssd_info {
- __u8 valid:1;
- __u8 type:7; /* subchannel type */
- __u8 chpid[8]; /* chpids */
- __u16 fla[8]; /* full link addresses */
-} __attribute__ ((packed));
+#include <asm/chpid.h>
+#include "chsc.h"
+#include "schid.h"

/*
* path management control word
@@ -109,7 +101,7 @@
struct schib schib; /* subchannel information block */
struct orb orb; /* operation request block */
struct ccw1 sense_ccw; /* static ccw for sense command */
- struct ssd_info ssd_info; /* subchannel description */
+ struct chsc_ssd_info ssd_info; /* subchannel description */
struct device dev; /* entry in device tree */
struct css_driver *driver;
} __attribute__ ((aligned(8)));
Index: quilt-2.6/drivers/s390/cio/css.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/css.c 2007-04-27 16:04:54.000000000 +0200
+++ quilt-2.6/drivers/s390/cio/css.c 2007-04-27 16:04:55.000000000 +0200
@@ -21,6 +21,7 @@
#include "chsc.h"
#include "device.h"
#include "idset.h"
+#include "chp.h"

int css_init_done = 0;
static int need_reprobe = 0;
@@ -125,8 +126,52 @@
mutex_unlock(&sch->reg_mutex);
}

-static int
-css_register_subchannel(struct subchannel *sch)
+static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
+{
+ int i;
+ int mask;
+
+ memset(ssd, 0, sizeof(struct chsc_ssd_info));
+ ssd->path_mask = pmcw->pim;
+ for (i = 0; i < 8; i++) {
+ mask = 0x80 >> i;
+ if (pmcw->pim & mask) {
+ chp_id_init(&ssd->chpid[i]);
+ ssd->chpid[i].id = pmcw->chpid[i];
+ }
+ }
+}
+
+static void ssd_register_chpids(struct chsc_ssd_info *ssd)
+{
+ int i;
+ int mask;
+
+ for (i = 0; i < 8; i++) {
+ mask = 0x80 >> i;
+ if (ssd->path_mask & mask)
+ if (!chp_is_registered(ssd->chpid[i]))
+ chp_new(ssd->chpid[i]);
+ }
+}
+
+void css_update_ssd_info(struct subchannel *sch)
+{
+ int ret;
+
+ if (cio_is_console(sch->schid)) {
+ /* Console is initialized too early for functions requiring
+ * memory allocation. */
+ ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
+ } else {
+ ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
+ if (ret)
+ ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
+ ssd_register_chpids(&sch->ssd_info);
+ }
+}
+
+static int css_register_subchannel(struct subchannel *sch)
{
int ret;

@@ -135,9 +180,7 @@
sch->dev.bus = &css_bus_type;
sch->dev.release = &css_subchannel_release;
sch->dev.groups = subch_attr_groups;
-
- css_get_ssd_info(sch);
-
+ css_update_ssd_info(sch);
/* make it known to the system */
ret = css_sch_device_register(sch);
if (ret) {
Index: quilt-2.6/drivers/s390/cio/css.h
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/css.h 2007-04-27 16:04:54.000000000 +0200
+++ quilt-2.6/drivers/s390/cio/css.h 2007-04-27 16:04:55.000000000 +0200
@@ -148,6 +148,7 @@
extern int for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *);
extern void css_process_crw(int, int);
extern void css_reiterate_subchannels(void);
+void css_update_ssd_info(struct subchannel *sch);

#define __MAX_SUBCHANNEL 65535
#define __MAX_SSID 3
Index: quilt-2.6/drivers/s390/cio/device.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/device.c 2007-04-27 16:04:54.000000000 +0200
+++ quilt-2.6/drivers/s390/cio/device.c 2007-04-27 16:04:55.000000000 +0200
@@ -216,12 +216,18 @@
chpids_show (struct device * dev, struct device_attribute *attr, char * buf)
{
struct subchannel *sch = to_subchannel(dev);
- struct ssd_info *ssd = &sch->ssd_info;
+ struct chsc_ssd_info *ssd = &sch->ssd_info;
ssize_t ret = 0;
int chp;
+ int mask;

- for (chp = 0; chp < 8; chp++)
- ret += sprintf (buf+ret, "%02x ", ssd->chpid[chp]);
+ for (chp = 0; chp < 8; chp++) {
+ mask = 0x80 >> chp;
+ if (ssd->path_mask & mask)
+ ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
+ else
+ ret += sprintf(buf + ret, "00 ");
+ }
ret += sprintf (buf+ret, "\n");
return min((ssize_t)PAGE_SIZE, ret);
}
Index: quilt-2.6/drivers/s390/cio/device_fsm.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/device_fsm.c 2007-04-27 16:04:54.000000000 +0200
+++ quilt-2.6/drivers/s390/cio/device_fsm.c 2007-04-27 16:04:55.000000000 +0200
@@ -246,6 +246,7 @@
*/
old_lpm = sch->lpm;
stsch(sch->schid, &sch->schib);
+ css_update_ssd_info(sch);
sch->lpm = sch->schib.pmcw.pam & sch->opm;
/* Check since device may again have become not operational. */
if (!sch->schib.pmcw.dnv)

--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.

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