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linux/drivers/s390/scsi/zfcp_qdio.c
Christof Schmitt c2af7545aa [SCSI] zfcp: Do not wait for SBALs on stopped queue
Trying to read the FC host statistics on an offline adapter results in
a 5 seconds wait. Reading the statistics tries to issue an exchange
port data request which first waits up to 5 seconds for an entry in
the request queue.

Change the strategy for getting a free SBAL to exit when the queue is
stopped. Reading the statistics will then fail without the wait.

Reviewed-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
2010-07-21 15:05:07 -07:00

494 lines
13 KiB
C

/*
* zfcp device driver
*
* Setup and helper functions to access QDIO.
*
* Copyright IBM Corporation 2002, 2010
*/
#define KMSG_COMPONENT "zfcp"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/slab.h>
#include "zfcp_ext.h"
#include "zfcp_qdio.h"
#define QBUFF_PER_PAGE (PAGE_SIZE / sizeof(struct qdio_buffer))
static int zfcp_qdio_buffers_enqueue(struct qdio_buffer **sbal)
{
int pos;
for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos += QBUFF_PER_PAGE) {
sbal[pos] = (struct qdio_buffer *) get_zeroed_page(GFP_KERNEL);
if (!sbal[pos])
return -ENOMEM;
}
for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos++)
if (pos % QBUFF_PER_PAGE)
sbal[pos] = sbal[pos - 1] + 1;
return 0;
}
static void zfcp_qdio_handler_error(struct zfcp_qdio *qdio, char *id)
{
struct zfcp_adapter *adapter = qdio->adapter;
dev_warn(&adapter->ccw_device->dev, "A QDIO problem occurred\n");
zfcp_erp_adapter_reopen(adapter,
ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED |
ZFCP_STATUS_COMMON_ERP_FAILED, id, NULL);
}
static void zfcp_qdio_zero_sbals(struct qdio_buffer *sbal[], int first, int cnt)
{
int i, sbal_idx;
for (i = first; i < first + cnt; i++) {
sbal_idx = i % QDIO_MAX_BUFFERS_PER_Q;
memset(sbal[sbal_idx], 0, sizeof(struct qdio_buffer));
}
}
/* this needs to be called prior to updating the queue fill level */
static inline void zfcp_qdio_account(struct zfcp_qdio *qdio)
{
unsigned long long now, span;
int free, used;
spin_lock(&qdio->stat_lock);
now = get_clock_monotonic();
span = (now - qdio->req_q_time) >> 12;
free = atomic_read(&qdio->req_q.count);
used = QDIO_MAX_BUFFERS_PER_Q - free;
qdio->req_q_util += used * span;
qdio->req_q_time = now;
spin_unlock(&qdio->stat_lock);
}
static void zfcp_qdio_int_req(struct ccw_device *cdev, unsigned int qdio_err,
int queue_no, int first, int count,
unsigned long parm)
{
struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;
struct zfcp_qdio_queue *queue = &qdio->req_q;
if (unlikely(qdio_err)) {
zfcp_dbf_hba_qdio(qdio->adapter->dbf, qdio_err, first,
count);
zfcp_qdio_handler_error(qdio, "qdireq1");
return;
}
/* cleanup all SBALs being program-owned now */
zfcp_qdio_zero_sbals(queue->sbal, first, count);
zfcp_qdio_account(qdio);
atomic_add(count, &queue->count);
wake_up(&qdio->req_q_wq);
}
static void zfcp_qdio_resp_put_back(struct zfcp_qdio *qdio, int processed)
{
struct zfcp_qdio_queue *queue = &qdio->resp_q;
struct ccw_device *cdev = qdio->adapter->ccw_device;
u8 count, start = queue->first;
unsigned int retval;
count = atomic_read(&queue->count) + processed;
retval = do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, start, count);
if (unlikely(retval)) {
atomic_set(&queue->count, count);
zfcp_erp_adapter_reopen(qdio->adapter, 0, "qdrpb_1", NULL);
} else {
queue->first += count;
queue->first %= QDIO_MAX_BUFFERS_PER_Q;
atomic_set(&queue->count, 0);
}
}
static void zfcp_qdio_int_resp(struct ccw_device *cdev, unsigned int qdio_err,
int queue_no, int first, int count,
unsigned long parm)
{
struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;
int sbal_idx, sbal_no;
if (unlikely(qdio_err)) {
zfcp_dbf_hba_qdio(qdio->adapter->dbf, qdio_err, first,
count);
zfcp_qdio_handler_error(qdio, "qdires1");
return;
}
/*
* go through all SBALs from input queue currently
* returned by QDIO layer
*/
for (sbal_no = 0; sbal_no < count; sbal_no++) {
sbal_idx = (first + sbal_no) % QDIO_MAX_BUFFERS_PER_Q;
/* go through all SBALEs of SBAL */
zfcp_fsf_reqid_check(qdio, sbal_idx);
}
/*
* put range of SBALs back to response queue
* (including SBALs which have already been free before)
*/
zfcp_qdio_resp_put_back(qdio, count);
}
static void zfcp_qdio_sbal_limit(struct zfcp_qdio *qdio,
struct zfcp_qdio_req *q_req, int max_sbals)
{
int count = atomic_read(&qdio->req_q.count);
count = min(count, max_sbals);
q_req->sbal_limit = (q_req->sbal_first + count - 1)
% QDIO_MAX_BUFFERS_PER_Q;
}
static struct qdio_buffer_element *
zfcp_qdio_sbal_chain(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
{
struct qdio_buffer_element *sbale;
/* set last entry flag in current SBALE of current SBAL */
sbale = zfcp_qdio_sbale_curr(qdio, q_req);
sbale->flags |= SBAL_FLAGS_LAST_ENTRY;
/* don't exceed last allowed SBAL */
if (q_req->sbal_last == q_req->sbal_limit)
return NULL;
/* set chaining flag in first SBALE of current SBAL */
sbale = zfcp_qdio_sbale_req(qdio, q_req);
sbale->flags |= SBAL_FLAGS0_MORE_SBALS;
/* calculate index of next SBAL */
q_req->sbal_last++;
q_req->sbal_last %= QDIO_MAX_BUFFERS_PER_Q;
/* keep this requests number of SBALs up-to-date */
q_req->sbal_number++;
/* start at first SBALE of new SBAL */
q_req->sbale_curr = 0;
/* set storage-block type for new SBAL */
sbale = zfcp_qdio_sbale_curr(qdio, q_req);
sbale->flags |= q_req->sbtype;
return sbale;
}
static struct qdio_buffer_element *
zfcp_qdio_sbale_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
{
if (q_req->sbale_curr == ZFCP_QDIO_LAST_SBALE_PER_SBAL)
return zfcp_qdio_sbal_chain(qdio, q_req);
q_req->sbale_curr++;
return zfcp_qdio_sbale_curr(qdio, q_req);
}
static void zfcp_qdio_undo_sbals(struct zfcp_qdio *qdio,
struct zfcp_qdio_req *q_req)
{
struct qdio_buffer **sbal = qdio->req_q.sbal;
int first = q_req->sbal_first;
int last = q_req->sbal_last;
int count = (last - first + QDIO_MAX_BUFFERS_PER_Q) %
QDIO_MAX_BUFFERS_PER_Q + 1;
zfcp_qdio_zero_sbals(sbal, first, count);
}
/**
* zfcp_qdio_sbals_from_sg - fill SBALs from scatter-gather list
* @qdio: pointer to struct zfcp_qdio
* @q_req: pointer to struct zfcp_qdio_req
* @sg: scatter-gather list
* @max_sbals: upper bound for number of SBALs to be used
* Returns: number of bytes, or error (negativ)
*/
int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
struct scatterlist *sg, int max_sbals)
{
struct qdio_buffer_element *sbale;
int bytes = 0;
/* figure out last allowed SBAL */
zfcp_qdio_sbal_limit(qdio, q_req, max_sbals);
/* set storage-block type for this request */
sbale = zfcp_qdio_sbale_req(qdio, q_req);
sbale->flags |= q_req->sbtype;
for (; sg; sg = sg_next(sg)) {
sbale = zfcp_qdio_sbale_next(qdio, q_req);
if (!sbale) {
atomic_inc(&qdio->req_q_full);
zfcp_qdio_undo_sbals(qdio, q_req);
return -EINVAL;
}
sbale->addr = sg_virt(sg);
sbale->length = sg->length;
bytes += sg->length;
}
/* assume that no other SBALEs are to follow in the same SBAL */
sbale = zfcp_qdio_sbale_curr(qdio, q_req);
sbale->flags |= SBAL_FLAGS_LAST_ENTRY;
return bytes;
}
static int zfcp_qdio_sbal_check(struct zfcp_qdio *qdio)
{
struct zfcp_qdio_queue *req_q = &qdio->req_q;
spin_lock_bh(&qdio->req_q_lock);
if (atomic_read(&req_q->count) ||
!(atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
return 1;
spin_unlock_bh(&qdio->req_q_lock);
return 0;
}
/**
* zfcp_qdio_sbal_get - get free sbal in request queue, wait if necessary
* @qdio: pointer to struct zfcp_qdio
*
* The req_q_lock must be held by the caller of this function, and
* this function may only be called from process context; it will
* sleep when waiting for a free sbal.
*
* Returns: 0 on success, -EIO if there is no free sbal after waiting.
*/
int zfcp_qdio_sbal_get(struct zfcp_qdio *qdio)
{
long ret;
spin_unlock_bh(&qdio->req_q_lock);
ret = wait_event_interruptible_timeout(qdio->req_q_wq,
zfcp_qdio_sbal_check(qdio), 5 * HZ);
if (!(atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
return -EIO;
if (ret > 0)
return 0;
if (!ret) {
atomic_inc(&qdio->req_q_full);
/* assume hanging outbound queue, try queue recovery */
zfcp_erp_adapter_reopen(qdio->adapter, 0, "qdsbg_1", NULL);
}
spin_lock_bh(&qdio->req_q_lock);
return -EIO;
}
/**
* zfcp_qdio_send - set PCI flag in first SBALE and send req to QDIO
* @qdio: pointer to struct zfcp_qdio
* @q_req: pointer to struct zfcp_qdio_req
* Returns: 0 on success, error otherwise
*/
int zfcp_qdio_send(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
{
struct zfcp_qdio_queue *req_q = &qdio->req_q;
int first = q_req->sbal_first;
int count = q_req->sbal_number;
int retval;
unsigned int qdio_flags = QDIO_FLAG_SYNC_OUTPUT;
zfcp_qdio_account(qdio);
retval = do_QDIO(qdio->adapter->ccw_device, qdio_flags, 0, first,
count);
if (unlikely(retval)) {
zfcp_qdio_zero_sbals(req_q->sbal, first, count);
return retval;
}
/* account for transferred buffers */
atomic_sub(count, &req_q->count);
req_q->first += count;
req_q->first %= QDIO_MAX_BUFFERS_PER_Q;
return 0;
}
static void zfcp_qdio_setup_init_data(struct qdio_initialize *id,
struct zfcp_qdio *qdio)
{
id->cdev = qdio->adapter->ccw_device;
id->q_format = QDIO_ZFCP_QFMT;
memcpy(id->adapter_name, dev_name(&id->cdev->dev), 8);
ASCEBC(id->adapter_name, 8);
id->qib_param_field_format = 0;
id->qib_param_field = NULL;
id->input_slib_elements = NULL;
id->output_slib_elements = NULL;
id->no_input_qs = 1;
id->no_output_qs = 1;
id->input_handler = zfcp_qdio_int_resp;
id->output_handler = zfcp_qdio_int_req;
id->int_parm = (unsigned long) qdio;
id->input_sbal_addr_array = (void **) (qdio->resp_q.sbal);
id->output_sbal_addr_array = (void **) (qdio->req_q.sbal);
}
/**
* zfcp_qdio_allocate - allocate queue memory and initialize QDIO data
* @adapter: pointer to struct zfcp_adapter
* Returns: -ENOMEM on memory allocation error or return value from
* qdio_allocate
*/
static int zfcp_qdio_allocate(struct zfcp_qdio *qdio)
{
struct qdio_initialize init_data;
if (zfcp_qdio_buffers_enqueue(qdio->req_q.sbal) ||
zfcp_qdio_buffers_enqueue(qdio->resp_q.sbal))
return -ENOMEM;
zfcp_qdio_setup_init_data(&init_data, qdio);
return qdio_allocate(&init_data);
}
/**
* zfcp_close_qdio - close qdio queues for an adapter
* @qdio: pointer to structure zfcp_qdio
*/
void zfcp_qdio_close(struct zfcp_qdio *qdio)
{
struct zfcp_qdio_queue *req_q;
int first, count;
if (!(atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
return;
/* clear QDIOUP flag, thus do_QDIO is not called during qdio_shutdown */
req_q = &qdio->req_q;
spin_lock_bh(&qdio->req_q_lock);
atomic_clear_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &qdio->adapter->status);
spin_unlock_bh(&qdio->req_q_lock);
wake_up(&qdio->req_q_wq);
qdio_shutdown(qdio->adapter->ccw_device,
QDIO_FLAG_CLEANUP_USING_CLEAR);
/* cleanup used outbound sbals */
count = atomic_read(&req_q->count);
if (count < QDIO_MAX_BUFFERS_PER_Q) {
first = (req_q->first + count) % QDIO_MAX_BUFFERS_PER_Q;
count = QDIO_MAX_BUFFERS_PER_Q - count;
zfcp_qdio_zero_sbals(req_q->sbal, first, count);
}
req_q->first = 0;
atomic_set(&req_q->count, 0);
qdio->resp_q.first = 0;
atomic_set(&qdio->resp_q.count, 0);
}
/**
* zfcp_qdio_open - prepare and initialize response queue
* @qdio: pointer to struct zfcp_qdio
* Returns: 0 on success, otherwise -EIO
*/
int zfcp_qdio_open(struct zfcp_qdio *qdio)
{
struct qdio_buffer_element *sbale;
struct qdio_initialize init_data;
struct ccw_device *cdev = qdio->adapter->ccw_device;
int cc;
if (atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP)
return -EIO;
zfcp_qdio_setup_init_data(&init_data, qdio);
if (qdio_establish(&init_data))
goto failed_establish;
if (qdio_activate(cdev))
goto failed_qdio;
for (cc = 0; cc < QDIO_MAX_BUFFERS_PER_Q; cc++) {
sbale = &(qdio->resp_q.sbal[cc]->element[0]);
sbale->length = 0;
sbale->flags = SBAL_FLAGS_LAST_ENTRY;
sbale->addr = NULL;
}
if (do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, 0,
QDIO_MAX_BUFFERS_PER_Q))
goto failed_qdio;
/* set index of first avalable SBALS / number of available SBALS */
qdio->req_q.first = 0;
atomic_set(&qdio->req_q.count, QDIO_MAX_BUFFERS_PER_Q);
return 0;
failed_qdio:
qdio_shutdown(cdev, QDIO_FLAG_CLEANUP_USING_CLEAR);
failed_establish:
dev_err(&cdev->dev,
"Setting up the QDIO connection to the FCP adapter failed\n");
return -EIO;
}
void zfcp_qdio_destroy(struct zfcp_qdio *qdio)
{
struct qdio_buffer **sbal_req, **sbal_resp;
int p;
if (!qdio)
return;
if (qdio->adapter->ccw_device)
qdio_free(qdio->adapter->ccw_device);
sbal_req = qdio->req_q.sbal;
sbal_resp = qdio->resp_q.sbal;
for (p = 0; p < QDIO_MAX_BUFFERS_PER_Q; p += QBUFF_PER_PAGE) {
free_page((unsigned long) sbal_req[p]);
free_page((unsigned long) sbal_resp[p]);
}
kfree(qdio);
}
int zfcp_qdio_setup(struct zfcp_adapter *adapter)
{
struct zfcp_qdio *qdio;
qdio = kzalloc(sizeof(struct zfcp_qdio), GFP_KERNEL);
if (!qdio)
return -ENOMEM;
qdio->adapter = adapter;
if (zfcp_qdio_allocate(qdio)) {
zfcp_qdio_destroy(qdio);
return -ENOMEM;
}
spin_lock_init(&qdio->req_q_lock);
spin_lock_init(&qdio->stat_lock);
adapter->qdio = qdio;
return 0;
}