[patch 10/34] dasd: optimize cpu usage in goodcase

From: Martin Schwidefsky
Date: Fri Aug 14 2009 - 07:26:37 EST


From: Stefan Haberland <stefan.haberland@xxxxxxxxxx>

remove unnecessary dbf call, remove string operations for magic

Signed-off-by: Stefan Haberland <stefan.haberland@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
---

drivers/s390/block/dasd.c | 21 +++++++-----------
drivers/s390/block/dasd_alias.c | 3 --
drivers/s390/block/dasd_diag.c | 3 --
drivers/s390/block/dasd_eckd.c | 45 ++++++++++++++++------------------------
drivers/s390/block/dasd_eer.c | 2 -
drivers/s390/block/dasd_fba.c | 7 ++----
drivers/s390/block/dasd_int.h | 11 +++++++--
7 files changed, 41 insertions(+), 51 deletions(-)

Index: quilt-2.6/drivers/s390/block/dasd_alias.c
===================================================================
--- quilt-2.6.orig/drivers/s390/block/dasd_alias.c
+++ quilt-2.6/drivers/s390/block/dasd_alias.c
@@ -379,8 +379,7 @@ static int read_unit_address_configurati
int rc;
unsigned long flags;

- cqr = dasd_kmalloc_request("ECKD",
- 1 /* PSF */ + 1 /* RSSD */ ,
+ cqr = dasd_kmalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */ + 1 /* RSSD */,
(sizeof(struct dasd_psf_prssd_data)),
device);
if (IS_ERR(cqr))
Index: quilt-2.6/drivers/s390/block/dasd.c
===================================================================
--- quilt-2.6.orig/drivers/s390/block/dasd.c
+++ quilt-2.6/drivers/s390/block/dasd.c
@@ -669,14 +669,14 @@ static void dasd_profile_end(struct dasd
* memory and 2) dasd_smalloc_request uses the static ccw memory
* that gets allocated for each device.
*/
-struct dasd_ccw_req *dasd_kmalloc_request(char *magic, int cplength,
+struct dasd_ccw_req *dasd_kmalloc_request(int magic, int cplength,
int datasize,
struct dasd_device *device)
{
struct dasd_ccw_req *cqr;

/* Sanity checks */
- BUG_ON( magic == NULL || datasize > PAGE_SIZE ||
+ BUG_ON(datasize > PAGE_SIZE ||
(cplength*sizeof(struct ccw1)) > PAGE_SIZE);

cqr = kzalloc(sizeof(struct dasd_ccw_req), GFP_ATOMIC);
@@ -700,14 +700,13 @@ struct dasd_ccw_req *dasd_kmalloc_reques
return ERR_PTR(-ENOMEM);
}
}
- strncpy((char *) &cqr->magic, magic, 4);
- ASCEBC((char *) &cqr->magic, 4);
+ cqr->magic = magic;
set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
dasd_get_device(device);
return cqr;
}

-struct dasd_ccw_req *dasd_smalloc_request(char *magic, int cplength,
+struct dasd_ccw_req *dasd_smalloc_request(int magic, int cplength,
int datasize,
struct dasd_device *device)
{
@@ -717,7 +716,7 @@ struct dasd_ccw_req *dasd_smalloc_reques
int size;

/* Sanity checks */
- BUG_ON( magic == NULL || datasize > PAGE_SIZE ||
+ BUG_ON(datasize > PAGE_SIZE ||
(cplength*sizeof(struct ccw1)) > PAGE_SIZE);

size = (sizeof(struct dasd_ccw_req) + 7L) & -8L;
@@ -744,8 +743,7 @@ struct dasd_ccw_req *dasd_smalloc_reques
cqr->data = data;
memset(cqr->data, 0, datasize);
}
- strncpy((char *) &cqr->magic, magic, 4);
- ASCEBC((char *) &cqr->magic, 4);
+ cqr->magic = magic;
set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
dasd_get_device(device);
return cqr;
@@ -899,9 +897,6 @@ int dasd_start_IO(struct dasd_ccw_req *c
switch (rc) {
case 0:
cqr->status = DASD_CQR_IN_IO;
- DBF_DEV_EVENT(DBF_DEBUG, device,
- "start_IO: request %p started successful",
- cqr);
break;
case -EBUSY:
DBF_DEV_EVENT(DBF_DEBUG, device, "%s",
@@ -2533,7 +2528,7 @@ EXPORT_SYMBOL_GPL(dasd_generic_restore_d
static struct dasd_ccw_req *dasd_generic_build_rdc(struct dasd_device *device,
void *rdc_buffer,
int rdc_buffer_size,
- char *magic)
+ int magic)
{
struct dasd_ccw_req *cqr;
struct ccw1 *ccw;
@@ -2564,7 +2559,7 @@ static struct dasd_ccw_req *dasd_generic
}


-int dasd_generic_read_dev_chars(struct dasd_device *device, char *magic,
+int dasd_generic_read_dev_chars(struct dasd_device *device, int magic,
void *rdc_buffer, int rdc_buffer_size)
{
int ret;
Index: quilt-2.6/drivers/s390/block/dasd_diag.c
===================================================================
--- quilt-2.6.orig/drivers/s390/block/dasd_diag.c
+++ quilt-2.6/drivers/s390/block/dasd_diag.c
@@ -523,8 +523,7 @@ static struct dasd_ccw_req *dasd_diag_bu
/* Build the request */
datasize = sizeof(struct dasd_diag_req) +
count*sizeof(struct dasd_diag_bio);
- cqr = dasd_smalloc_request(dasd_diag_discipline.name, 0,
- datasize, memdev);
+ cqr = dasd_smalloc_request(DASD_DIAG_MAGIC, 0, datasize, memdev);
if (IS_ERR(cqr))
return cqr;

Index: quilt-2.6/drivers/s390/block/dasd_eckd.c
===================================================================
--- quilt-2.6.orig/drivers/s390/block/dasd_eckd.c
+++ quilt-2.6/drivers/s390/block/dasd_eckd.c
@@ -730,7 +730,8 @@ static struct dasd_ccw_req *dasd_eckd_bu
struct dasd_ccw_req *cqr;
struct ccw1 *ccw;

- cqr = dasd_smalloc_request("ECKD", 1 /* RCD */, ciw->count, device);
+ cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* RCD */, ciw->count,
+ device);

if (IS_ERR(cqr)) {
DBF_DEV_EVENT(DBF_WARNING, device, "%s",
@@ -934,8 +935,7 @@ static int dasd_eckd_read_features(struc
struct dasd_eckd_private *private;

private = (struct dasd_eckd_private *) device->private;
- cqr = dasd_smalloc_request(dasd_eckd_discipline.name,
- 1 /* PSF */ + 1 /* RSSD */ ,
+ cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */ + 1 /* RSSD */,
(sizeof(struct dasd_psf_prssd_data) +
sizeof(struct dasd_rssd_features)),
device);
@@ -998,7 +998,7 @@ static struct dasd_ccw_req *dasd_eckd_bu
struct dasd_psf_ssc_data *psf_ssc_data;
struct ccw1 *ccw;

- cqr = dasd_smalloc_request("ECKD", 1 /* PSF */ ,
+ cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */ ,
sizeof(struct dasd_psf_ssc_data),
device);

@@ -1149,8 +1149,8 @@ dasd_eckd_check_characteristics(struct d
goto out_err3;

/* Read Device Characteristics */
- rc = dasd_generic_read_dev_chars(device, "ECKD", &private->rdc_data,
- 64);
+ rc = dasd_generic_read_dev_chars(device, DASD_ECKD_MAGIC,
+ &private->rdc_data, 64);
if (rc) {
DBF_EVENT(DBF_WARNING,
"Read device characteristics failed, rc=%d for "
@@ -1217,8 +1217,7 @@ dasd_eckd_analysis_ccw(struct dasd_devic

cplength = 8;
datasize = sizeof(struct DE_eckd_data) + 2*sizeof(struct LO_eckd_data);
- cqr = dasd_smalloc_request(dasd_eckd_discipline.name,
- cplength, datasize, device);
+ cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, cplength, datasize, device);
if (IS_ERR(cqr))
return cqr;
ccw = cqr->cpaddr;
@@ -1499,8 +1498,7 @@ dasd_eckd_format_device(struct dasd_devi
return ERR_PTR(-EINVAL);
}
/* Allocate the format ccw request. */
- fcp = dasd_smalloc_request(dasd_eckd_discipline.name,
- cplength, datasize, device);
+ fcp = dasd_smalloc_request(DASD_ECKD_MAGIC, cplength, datasize, device);
if (IS_ERR(fcp))
return fcp;

@@ -1783,8 +1781,8 @@ static struct dasd_ccw_req *dasd_eckd_bu
datasize += count*sizeof(struct LO_eckd_data);
}
/* Allocate the ccw request. */
- cqr = dasd_smalloc_request(dasd_eckd_discipline.name,
- cplength, datasize, startdev);
+ cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, cplength, datasize,
+ startdev);
if (IS_ERR(cqr))
return cqr;
ccw = cqr->cpaddr;
@@ -1948,8 +1946,8 @@ static struct dasd_ccw_req *dasd_eckd_bu
cidaw * sizeof(unsigned long long);

/* Allocate the ccw request. */
- cqr = dasd_smalloc_request(dasd_eckd_discipline.name,
- cplength, datasize, startdev);
+ cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, cplength, datasize,
+ startdev);
if (IS_ERR(cqr))
return cqr;
ccw = cqr->cpaddr;
@@ -2249,8 +2247,7 @@ static struct dasd_ccw_req *dasd_eckd_bu

/* Allocate the ccw request. */
itcw_size = itcw_calc_size(0, ctidaw, 0);
- cqr = dasd_smalloc_request(dasd_eckd_discipline.name,
- 0, itcw_size, startdev);
+ cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 0, itcw_size, startdev);
if (IS_ERR(cqr))
return cqr;

@@ -2557,8 +2554,7 @@ dasd_eckd_release(struct dasd_device *de
if (!capable(CAP_SYS_ADMIN))
return -EACCES;

- cqr = dasd_smalloc_request(dasd_eckd_discipline.name,
- 1, 32, device);
+ cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1, 32, device);
if (IS_ERR(cqr)) {
DBF_DEV_EVENT(DBF_WARNING, device, "%s",
"Could not allocate initialization request");
@@ -2600,8 +2596,7 @@ dasd_eckd_reserve(struct dasd_device *de
if (!capable(CAP_SYS_ADMIN))
return -EACCES;

- cqr = dasd_smalloc_request(dasd_eckd_discipline.name,
- 1, 32, device);
+ cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1, 32, device);
if (IS_ERR(cqr)) {
DBF_DEV_EVENT(DBF_WARNING, device, "%s",
"Could not allocate initialization request");
@@ -2642,8 +2637,7 @@ dasd_eckd_steal_lock(struct dasd_device
if (!capable(CAP_SYS_ADMIN))
return -EACCES;

- cqr = dasd_smalloc_request(dasd_eckd_discipline.name,
- 1, 32, device);
+ cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1, 32, device);
if (IS_ERR(cqr)) {
DBF_DEV_EVENT(DBF_WARNING, device, "%s",
"Could not allocate initialization request");
@@ -2681,8 +2675,7 @@ dasd_eckd_performance(struct dasd_device
struct ccw1 *ccw;
int rc;

- cqr = dasd_smalloc_request(dasd_eckd_discipline.name,
- 1 /* PSF */ + 1 /* RSSD */ ,
+ cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */ + 1 /* RSSD */,
(sizeof(struct dasd_psf_prssd_data) +
sizeof(struct dasd_rssd_perf_stats_t)),
device);
@@ -2828,7 +2821,7 @@ static int dasd_symm_io(struct dasd_devi
}

/* setup CCWs for PSF + RSSD */
- cqr = dasd_smalloc_request("ECKD", 2 , 0, device);
+ cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 2 , 0, device);
if (IS_ERR(cqr)) {
DBF_DEV_EVENT(DBF_WARNING, device, "%s",
"Could not allocate initialization request");
@@ -3254,7 +3247,7 @@ int dasd_eckd_restore_device(struct dasd

/* Read Device Characteristics */
memset(&private->rdc_data, 0, sizeof(private->rdc_data));
- rc = dasd_generic_read_dev_chars(device, "ECKD",
+ rc = dasd_generic_read_dev_chars(device, DASD_ECKD_MAGIC,
&private->rdc_data, 64);
if (rc) {
DBF_EVENT(DBF_WARNING,
Index: quilt-2.6/drivers/s390/block/dasd_eer.c
===================================================================
--- quilt-2.6.orig/drivers/s390/block/dasd_eer.c
+++ quilt-2.6/drivers/s390/block/dasd_eer.c
@@ -464,7 +464,7 @@ int dasd_eer_enable(struct dasd_device *
if (!device->discipline || strcmp(device->discipline->name, "ECKD"))
return -EPERM; /* FIXME: -EMEDIUMTYPE ? */

- cqr = dasd_kmalloc_request("ECKD", 1 /* SNSS */,
+ cqr = dasd_kmalloc_request(DASD_ECKD_MAGIC, 1 /* SNSS */,
SNSS_DATA_SIZE, device);
if (IS_ERR(cqr))
return -ENOMEM;
Index: quilt-2.6/drivers/s390/block/dasd_fba.c
===================================================================
--- quilt-2.6.orig/drivers/s390/block/dasd_fba.c
+++ quilt-2.6/drivers/s390/block/dasd_fba.c
@@ -152,8 +152,8 @@ dasd_fba_check_characteristics(struct da
block->base = device;

/* Read Device Characteristics */
- rc = dasd_generic_read_dev_chars(device, "FBA ", &private->rdc_data,
- 32);
+ rc = dasd_generic_read_dev_chars(device, DASD_FBA_MAGIC,
+ &private->rdc_data, 32);
if (rc) {
DBF_EVENT(DBF_WARNING, "Read device characteristics returned "
"error %d for device: %s",
@@ -305,8 +305,7 @@ static struct dasd_ccw_req *dasd_fba_bui
datasize += (count - 1)*sizeof(struct LO_fba_data);
}
/* Allocate the ccw request. */
- cqr = dasd_smalloc_request(dasd_fba_discipline.name,
- cplength, datasize, memdev);
+ cqr = dasd_smalloc_request(DASD_FBA_MAGIC, cplength, datasize, memdev);
if (IS_ERR(cqr))
return cqr;
ccw = cqr->cpaddr;
Index: quilt-2.6/drivers/s390/block/dasd_int.h
===================================================================
--- quilt-2.6.orig/drivers/s390/block/dasd_int.h
+++ quilt-2.6/drivers/s390/block/dasd_int.h
@@ -59,6 +59,11 @@
#include <asm/dasd.h>
#include <asm/idals.h>

+/* DASD discipline magic */
+#define DASD_ECKD_MAGIC 0xC5C3D2C4
+#define DASD_DIAG_MAGIC 0xC4C9C1C7
+#define DASD_FBA_MAGIC 0xC6C2C140
+
/*
* SECTION: Type definitions
*/
@@ -540,9 +545,9 @@ extern struct block_device_operations da
extern struct kmem_cache *dasd_page_cache;

struct dasd_ccw_req *
-dasd_kmalloc_request(char *, int, int, struct dasd_device *);
+dasd_kmalloc_request(int , int, int, struct dasd_device *);
struct dasd_ccw_req *
-dasd_smalloc_request(char *, int, int, struct dasd_device *);
+dasd_smalloc_request(int , int, int, struct dasd_device *);
void dasd_kfree_request(struct dasd_ccw_req *, struct dasd_device *);
void dasd_sfree_request(struct dasd_ccw_req *, struct dasd_device *);

@@ -587,7 +592,7 @@ void dasd_generic_handle_state_change(st
int dasd_generic_pm_freeze(struct ccw_device *);
int dasd_generic_restore_device(struct ccw_device *);

-int dasd_generic_read_dev_chars(struct dasd_device *, char *, void *, int);
+int dasd_generic_read_dev_chars(struct dasd_device *, int, void *, int);
char *dasd_get_sense(struct irb *);

/* externals in dasd_devmap.c */

--
blue skies,
Martin.

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

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