mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-25 21:54:06 +08:00
18f87a67e6
This patch improves the Fibre Channel port scan behaviour of the zfcp lldd. Without it the zfcp device driver may churn up the storage area network by excessive scanning and scan bursts, particularly in big virtual server environments, potentially resulting in interference of virtual servers and reduced availability of storage connectivity. The two main issues as to the zfcp device drivers automatic port scan in virtual server environments are frequency and simultaneity. On the one hand, there is no point in allowing lots of ports scans in a row. It makes sense, though, to make sure that a scan is conducted eventually if there has been any indication for potential SAN changes. On the other hand, lots of virtual servers receiving the same indication for a SAN change had better not attempt to conduct a scan instantly, that is, at the same time. Hence this patch has a two-fold approach for better port scanning: the introduction of a rate limit to amend frequency issues, and the introduction of a short random backoff to amend simultaneity issues. Both approaches boil down to deferred port scans, with delays comprising parts for both approaches. The new port scan behaviour is summarised best by: NEW: NEW: no_auto_port_rescan random rate flush backoff limit =wait adapter resume/thaw yes yes no yes* adapter online (user) no yes no yes* port rescan (user) no no no yes adapter recovery (user) yes yes yes no adapter recovery (other) yes yes yes no incoming ELS yes yes yes no incoming ELS lost yes yes yes no Implementation is straight-forward by converting an existing worker to a delayed worker. But care is needed whenever that worker is going to be flushed (in order to make sure work has been completed), since a flush operation cancels the timer set up for deferred execution (see * above). There is a small race window whenever a port scan work starts running up to the point in time of storing the time stamp for that port scan. The impact is negligible. Closing that gap isn't trivial, though, and would the destroy the beauty of a simple work-to-delayed-work conversion. Signed-off-by: Martin Peschke <mpeschke@linux.vnet.ibm.com> Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
582 lines
15 KiB
C
582 lines
15 KiB
C
/*
|
|
* zfcp device driver
|
|
*
|
|
* Module interface and handling of zfcp data structures.
|
|
*
|
|
* Copyright IBM Corp. 2002, 2013
|
|
*/
|
|
|
|
/*
|
|
* Driver authors:
|
|
* Martin Peschke (originator of the driver)
|
|
* Raimund Schroeder
|
|
* Aron Zeh
|
|
* Wolfgang Taphorn
|
|
* Stefan Bader
|
|
* Heiko Carstens (kernel 2.6 port of the driver)
|
|
* Andreas Herrmann
|
|
* Maxim Shchetynin
|
|
* Volker Sameske
|
|
* Ralph Wuerthner
|
|
* Michael Loehr
|
|
* Swen Schillig
|
|
* Christof Schmitt
|
|
* Martin Petermann
|
|
* Sven Schuetz
|
|
* Steffen Maier
|
|
*/
|
|
|
|
#define KMSG_COMPONENT "zfcp"
|
|
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
|
|
|
|
#include <linux/miscdevice.h>
|
|
#include <linux/seq_file.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/module.h>
|
|
#include "zfcp_ext.h"
|
|
#include "zfcp_fc.h"
|
|
#include "zfcp_reqlist.h"
|
|
|
|
#define ZFCP_BUS_ID_SIZE 20
|
|
|
|
MODULE_AUTHOR("IBM Deutschland Entwicklung GmbH - linux390@de.ibm.com");
|
|
MODULE_DESCRIPTION("FCP HBA driver");
|
|
MODULE_LICENSE("GPL");
|
|
|
|
static char *init_device;
|
|
module_param_named(device, init_device, charp, 0400);
|
|
MODULE_PARM_DESC(device, "specify initial device");
|
|
|
|
static struct kmem_cache * __init zfcp_cache_hw_align(const char *name,
|
|
unsigned long size)
|
|
{
|
|
return kmem_cache_create(name, size, roundup_pow_of_two(size), 0, NULL);
|
|
}
|
|
|
|
static void __init zfcp_init_device_configure(char *busid, u64 wwpn, u64 lun)
|
|
{
|
|
struct ccw_device *cdev;
|
|
struct zfcp_adapter *adapter;
|
|
struct zfcp_port *port;
|
|
|
|
cdev = get_ccwdev_by_busid(&zfcp_ccw_driver, busid);
|
|
if (!cdev)
|
|
return;
|
|
|
|
if (ccw_device_set_online(cdev))
|
|
goto out_ccw_device;
|
|
|
|
adapter = zfcp_ccw_adapter_by_cdev(cdev);
|
|
if (!adapter)
|
|
goto out_ccw_device;
|
|
|
|
port = zfcp_get_port_by_wwpn(adapter, wwpn);
|
|
if (!port)
|
|
goto out_port;
|
|
flush_work(&port->rport_work);
|
|
|
|
zfcp_unit_add(port, lun);
|
|
put_device(&port->dev);
|
|
|
|
out_port:
|
|
zfcp_ccw_adapter_put(adapter);
|
|
out_ccw_device:
|
|
put_device(&cdev->dev);
|
|
return;
|
|
}
|
|
|
|
static void __init zfcp_init_device_setup(char *devstr)
|
|
{
|
|
char *token;
|
|
char *str, *str_saved;
|
|
char busid[ZFCP_BUS_ID_SIZE];
|
|
u64 wwpn, lun;
|
|
|
|
/* duplicate devstr and keep the original for sysfs presentation*/
|
|
str_saved = kstrdup(devstr, GFP_KERNEL);
|
|
str = str_saved;
|
|
if (!str)
|
|
return;
|
|
|
|
token = strsep(&str, ",");
|
|
if (!token || strlen(token) >= ZFCP_BUS_ID_SIZE)
|
|
goto err_out;
|
|
strncpy(busid, token, ZFCP_BUS_ID_SIZE);
|
|
|
|
token = strsep(&str, ",");
|
|
if (!token || kstrtoull(token, 0, (unsigned long long *) &wwpn))
|
|
goto err_out;
|
|
|
|
token = strsep(&str, ",");
|
|
if (!token || kstrtoull(token, 0, (unsigned long long *) &lun))
|
|
goto err_out;
|
|
|
|
kfree(str_saved);
|
|
zfcp_init_device_configure(busid, wwpn, lun);
|
|
return;
|
|
|
|
err_out:
|
|
kfree(str_saved);
|
|
pr_err("%s is not a valid SCSI device\n", devstr);
|
|
}
|
|
|
|
static int __init zfcp_module_init(void)
|
|
{
|
|
int retval = -ENOMEM;
|
|
|
|
zfcp_fsf_qtcb_cache = zfcp_cache_hw_align("zfcp_fsf_qtcb",
|
|
sizeof(struct fsf_qtcb));
|
|
if (!zfcp_fsf_qtcb_cache)
|
|
goto out_qtcb_cache;
|
|
|
|
zfcp_fc_req_cache = zfcp_cache_hw_align("zfcp_fc_req",
|
|
sizeof(struct zfcp_fc_req));
|
|
if (!zfcp_fc_req_cache)
|
|
goto out_fc_cache;
|
|
|
|
zfcp_scsi_transport_template =
|
|
fc_attach_transport(&zfcp_transport_functions);
|
|
if (!zfcp_scsi_transport_template)
|
|
goto out_transport;
|
|
scsi_transport_reserve_device(zfcp_scsi_transport_template,
|
|
sizeof(struct zfcp_scsi_dev));
|
|
|
|
retval = ccw_driver_register(&zfcp_ccw_driver);
|
|
if (retval) {
|
|
pr_err("The zfcp device driver could not register with "
|
|
"the common I/O layer\n");
|
|
goto out_ccw_register;
|
|
}
|
|
|
|
if (init_device)
|
|
zfcp_init_device_setup(init_device);
|
|
return 0;
|
|
|
|
out_ccw_register:
|
|
fc_release_transport(zfcp_scsi_transport_template);
|
|
out_transport:
|
|
kmem_cache_destroy(zfcp_fc_req_cache);
|
|
out_fc_cache:
|
|
kmem_cache_destroy(zfcp_fsf_qtcb_cache);
|
|
out_qtcb_cache:
|
|
return retval;
|
|
}
|
|
|
|
module_init(zfcp_module_init);
|
|
|
|
static void __exit zfcp_module_exit(void)
|
|
{
|
|
ccw_driver_unregister(&zfcp_ccw_driver);
|
|
fc_release_transport(zfcp_scsi_transport_template);
|
|
kmem_cache_destroy(zfcp_fc_req_cache);
|
|
kmem_cache_destroy(zfcp_fsf_qtcb_cache);
|
|
}
|
|
|
|
module_exit(zfcp_module_exit);
|
|
|
|
/**
|
|
* zfcp_get_port_by_wwpn - find port in port list of adapter by wwpn
|
|
* @adapter: pointer to adapter to search for port
|
|
* @wwpn: wwpn to search for
|
|
*
|
|
* Returns: pointer to zfcp_port or NULL
|
|
*/
|
|
struct zfcp_port *zfcp_get_port_by_wwpn(struct zfcp_adapter *adapter,
|
|
u64 wwpn)
|
|
{
|
|
unsigned long flags;
|
|
struct zfcp_port *port;
|
|
|
|
read_lock_irqsave(&adapter->port_list_lock, flags);
|
|
list_for_each_entry(port, &adapter->port_list, list)
|
|
if (port->wwpn == wwpn) {
|
|
if (!get_device(&port->dev))
|
|
port = NULL;
|
|
read_unlock_irqrestore(&adapter->port_list_lock, flags);
|
|
return port;
|
|
}
|
|
read_unlock_irqrestore(&adapter->port_list_lock, flags);
|
|
return NULL;
|
|
}
|
|
|
|
static int zfcp_allocate_low_mem_buffers(struct zfcp_adapter *adapter)
|
|
{
|
|
adapter->pool.erp_req =
|
|
mempool_create_kmalloc_pool(1, sizeof(struct zfcp_fsf_req));
|
|
if (!adapter->pool.erp_req)
|
|
return -ENOMEM;
|
|
|
|
adapter->pool.gid_pn_req =
|
|
mempool_create_kmalloc_pool(1, sizeof(struct zfcp_fsf_req));
|
|
if (!adapter->pool.gid_pn_req)
|
|
return -ENOMEM;
|
|
|
|
adapter->pool.scsi_req =
|
|
mempool_create_kmalloc_pool(1, sizeof(struct zfcp_fsf_req));
|
|
if (!adapter->pool.scsi_req)
|
|
return -ENOMEM;
|
|
|
|
adapter->pool.scsi_abort =
|
|
mempool_create_kmalloc_pool(1, sizeof(struct zfcp_fsf_req));
|
|
if (!adapter->pool.scsi_abort)
|
|
return -ENOMEM;
|
|
|
|
adapter->pool.status_read_req =
|
|
mempool_create_kmalloc_pool(FSF_STATUS_READS_RECOM,
|
|
sizeof(struct zfcp_fsf_req));
|
|
if (!adapter->pool.status_read_req)
|
|
return -ENOMEM;
|
|
|
|
adapter->pool.qtcb_pool =
|
|
mempool_create_slab_pool(4, zfcp_fsf_qtcb_cache);
|
|
if (!adapter->pool.qtcb_pool)
|
|
return -ENOMEM;
|
|
|
|
BUILD_BUG_ON(sizeof(struct fsf_status_read_buffer) > PAGE_SIZE);
|
|
adapter->pool.sr_data =
|
|
mempool_create_page_pool(FSF_STATUS_READS_RECOM, 0);
|
|
if (!adapter->pool.sr_data)
|
|
return -ENOMEM;
|
|
|
|
adapter->pool.gid_pn =
|
|
mempool_create_slab_pool(1, zfcp_fc_req_cache);
|
|
if (!adapter->pool.gid_pn)
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void zfcp_free_low_mem_buffers(struct zfcp_adapter *adapter)
|
|
{
|
|
if (adapter->pool.erp_req)
|
|
mempool_destroy(adapter->pool.erp_req);
|
|
if (adapter->pool.scsi_req)
|
|
mempool_destroy(adapter->pool.scsi_req);
|
|
if (adapter->pool.scsi_abort)
|
|
mempool_destroy(adapter->pool.scsi_abort);
|
|
if (adapter->pool.qtcb_pool)
|
|
mempool_destroy(adapter->pool.qtcb_pool);
|
|
if (adapter->pool.status_read_req)
|
|
mempool_destroy(adapter->pool.status_read_req);
|
|
if (adapter->pool.sr_data)
|
|
mempool_destroy(adapter->pool.sr_data);
|
|
if (adapter->pool.gid_pn)
|
|
mempool_destroy(adapter->pool.gid_pn);
|
|
}
|
|
|
|
/**
|
|
* zfcp_status_read_refill - refill the long running status_read_requests
|
|
* @adapter: ptr to struct zfcp_adapter for which the buffers should be refilled
|
|
*
|
|
* Returns: 0 on success, 1 otherwise
|
|
*
|
|
* if there are 16 or more status_read requests missing an adapter_reopen
|
|
* is triggered
|
|
*/
|
|
int zfcp_status_read_refill(struct zfcp_adapter *adapter)
|
|
{
|
|
while (atomic_read(&adapter->stat_miss) > 0)
|
|
if (zfcp_fsf_status_read(adapter->qdio)) {
|
|
if (atomic_read(&adapter->stat_miss) >=
|
|
adapter->stat_read_buf_num) {
|
|
zfcp_erp_adapter_reopen(adapter, 0, "axsref1");
|
|
return 1;
|
|
}
|
|
break;
|
|
} else
|
|
atomic_dec(&adapter->stat_miss);
|
|
return 0;
|
|
}
|
|
|
|
static void _zfcp_status_read_scheduler(struct work_struct *work)
|
|
{
|
|
zfcp_status_read_refill(container_of(work, struct zfcp_adapter,
|
|
stat_work));
|
|
}
|
|
|
|
static void zfcp_print_sl(struct seq_file *m, struct service_level *sl)
|
|
{
|
|
struct zfcp_adapter *adapter =
|
|
container_of(sl, struct zfcp_adapter, service_level);
|
|
|
|
seq_printf(m, "zfcp: %s microcode level %x\n",
|
|
dev_name(&adapter->ccw_device->dev),
|
|
adapter->fsf_lic_version);
|
|
}
|
|
|
|
static int zfcp_setup_adapter_work_queue(struct zfcp_adapter *adapter)
|
|
{
|
|
char name[TASK_COMM_LEN];
|
|
|
|
snprintf(name, sizeof(name), "zfcp_q_%s",
|
|
dev_name(&adapter->ccw_device->dev));
|
|
adapter->work_queue = create_singlethread_workqueue(name);
|
|
|
|
if (adapter->work_queue)
|
|
return 0;
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static void zfcp_destroy_adapter_work_queue(struct zfcp_adapter *adapter)
|
|
{
|
|
if (adapter->work_queue)
|
|
destroy_workqueue(adapter->work_queue);
|
|
adapter->work_queue = NULL;
|
|
|
|
}
|
|
|
|
/**
|
|
* zfcp_adapter_enqueue - enqueue a new adapter to the list
|
|
* @ccw_device: pointer to the struct cc_device
|
|
*
|
|
* Returns: struct zfcp_adapter*
|
|
* Enqueues an adapter at the end of the adapter list in the driver data.
|
|
* All adapter internal structures are set up.
|
|
* Proc-fs entries are also created.
|
|
*/
|
|
struct zfcp_adapter *zfcp_adapter_enqueue(struct ccw_device *ccw_device)
|
|
{
|
|
struct zfcp_adapter *adapter;
|
|
|
|
if (!get_device(&ccw_device->dev))
|
|
return ERR_PTR(-ENODEV);
|
|
|
|
adapter = kzalloc(sizeof(struct zfcp_adapter), GFP_KERNEL);
|
|
if (!adapter) {
|
|
put_device(&ccw_device->dev);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
kref_init(&adapter->ref);
|
|
|
|
ccw_device->handler = NULL;
|
|
adapter->ccw_device = ccw_device;
|
|
|
|
INIT_WORK(&adapter->stat_work, _zfcp_status_read_scheduler);
|
|
INIT_DELAYED_WORK(&adapter->scan_work, zfcp_fc_scan_ports);
|
|
INIT_WORK(&adapter->ns_up_work, zfcp_fc_sym_name_update);
|
|
|
|
adapter->next_port_scan = jiffies;
|
|
|
|
if (zfcp_qdio_setup(adapter))
|
|
goto failed;
|
|
|
|
if (zfcp_allocate_low_mem_buffers(adapter))
|
|
goto failed;
|
|
|
|
adapter->req_list = zfcp_reqlist_alloc();
|
|
if (!adapter->req_list)
|
|
goto failed;
|
|
|
|
if (zfcp_dbf_adapter_register(adapter))
|
|
goto failed;
|
|
|
|
if (zfcp_setup_adapter_work_queue(adapter))
|
|
goto failed;
|
|
|
|
if (zfcp_fc_gs_setup(adapter))
|
|
goto failed;
|
|
|
|
rwlock_init(&adapter->port_list_lock);
|
|
INIT_LIST_HEAD(&adapter->port_list);
|
|
|
|
INIT_LIST_HEAD(&adapter->events.list);
|
|
INIT_WORK(&adapter->events.work, zfcp_fc_post_event);
|
|
spin_lock_init(&adapter->events.list_lock);
|
|
|
|
init_waitqueue_head(&adapter->erp_ready_wq);
|
|
init_waitqueue_head(&adapter->erp_done_wqh);
|
|
|
|
INIT_LIST_HEAD(&adapter->erp_ready_head);
|
|
INIT_LIST_HEAD(&adapter->erp_running_head);
|
|
|
|
rwlock_init(&adapter->erp_lock);
|
|
rwlock_init(&adapter->abort_lock);
|
|
|
|
if (zfcp_erp_thread_setup(adapter))
|
|
goto failed;
|
|
|
|
adapter->service_level.seq_print = zfcp_print_sl;
|
|
|
|
dev_set_drvdata(&ccw_device->dev, adapter);
|
|
|
|
if (sysfs_create_group(&ccw_device->dev.kobj,
|
|
&zfcp_sysfs_adapter_attrs))
|
|
goto failed;
|
|
|
|
/* report size limit per scatter-gather segment */
|
|
adapter->dma_parms.max_segment_size = ZFCP_QDIO_SBALE_LEN;
|
|
adapter->ccw_device->dev.dma_parms = &adapter->dma_parms;
|
|
|
|
adapter->stat_read_buf_num = FSF_STATUS_READS_RECOM;
|
|
|
|
if (!zfcp_scsi_adapter_register(adapter))
|
|
return adapter;
|
|
|
|
failed:
|
|
zfcp_adapter_unregister(adapter);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
void zfcp_adapter_unregister(struct zfcp_adapter *adapter)
|
|
{
|
|
struct ccw_device *cdev = adapter->ccw_device;
|
|
|
|
cancel_delayed_work_sync(&adapter->scan_work);
|
|
cancel_work_sync(&adapter->stat_work);
|
|
cancel_work_sync(&adapter->ns_up_work);
|
|
zfcp_destroy_adapter_work_queue(adapter);
|
|
|
|
zfcp_fc_wka_ports_force_offline(adapter->gs);
|
|
zfcp_scsi_adapter_unregister(adapter);
|
|
sysfs_remove_group(&cdev->dev.kobj, &zfcp_sysfs_adapter_attrs);
|
|
|
|
zfcp_erp_thread_kill(adapter);
|
|
zfcp_dbf_adapter_unregister(adapter);
|
|
zfcp_qdio_destroy(adapter->qdio);
|
|
|
|
zfcp_ccw_adapter_put(adapter); /* final put to release */
|
|
}
|
|
|
|
/**
|
|
* zfcp_adapter_release - remove the adapter from the resource list
|
|
* @ref: pointer to struct kref
|
|
* locks: adapter list write lock is assumed to be held by caller
|
|
*/
|
|
void zfcp_adapter_release(struct kref *ref)
|
|
{
|
|
struct zfcp_adapter *adapter = container_of(ref, struct zfcp_adapter,
|
|
ref);
|
|
struct ccw_device *cdev = adapter->ccw_device;
|
|
|
|
dev_set_drvdata(&adapter->ccw_device->dev, NULL);
|
|
zfcp_fc_gs_destroy(adapter);
|
|
zfcp_free_low_mem_buffers(adapter);
|
|
kfree(adapter->req_list);
|
|
kfree(adapter->fc_stats);
|
|
kfree(adapter->stats_reset_data);
|
|
kfree(adapter);
|
|
put_device(&cdev->dev);
|
|
}
|
|
|
|
static void zfcp_port_release(struct device *dev)
|
|
{
|
|
struct zfcp_port *port = container_of(dev, struct zfcp_port, dev);
|
|
|
|
zfcp_ccw_adapter_put(port->adapter);
|
|
kfree(port);
|
|
}
|
|
|
|
/**
|
|
* zfcp_port_enqueue - enqueue port to port list of adapter
|
|
* @adapter: adapter where remote port is added
|
|
* @wwpn: WWPN of the remote port to be enqueued
|
|
* @status: initial status for the port
|
|
* @d_id: destination id of the remote port to be enqueued
|
|
* Returns: pointer to enqueued port on success, ERR_PTR on error
|
|
*
|
|
* All port internal structures are set up and the sysfs entry is generated.
|
|
* d_id is used to enqueue ports with a well known address like the Directory
|
|
* Service for nameserver lookup.
|
|
*/
|
|
struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn,
|
|
u32 status, u32 d_id)
|
|
{
|
|
struct zfcp_port *port;
|
|
int retval = -ENOMEM;
|
|
|
|
kref_get(&adapter->ref);
|
|
|
|
port = zfcp_get_port_by_wwpn(adapter, wwpn);
|
|
if (port) {
|
|
put_device(&port->dev);
|
|
retval = -EEXIST;
|
|
goto err_out;
|
|
}
|
|
|
|
port = kzalloc(sizeof(struct zfcp_port), GFP_KERNEL);
|
|
if (!port)
|
|
goto err_out;
|
|
|
|
rwlock_init(&port->unit_list_lock);
|
|
INIT_LIST_HEAD(&port->unit_list);
|
|
atomic_set(&port->units, 0);
|
|
|
|
INIT_WORK(&port->gid_pn_work, zfcp_fc_port_did_lookup);
|
|
INIT_WORK(&port->test_link_work, zfcp_fc_link_test_work);
|
|
INIT_WORK(&port->rport_work, zfcp_scsi_rport_work);
|
|
|
|
port->adapter = adapter;
|
|
port->d_id = d_id;
|
|
port->wwpn = wwpn;
|
|
port->rport_task = RPORT_NONE;
|
|
port->dev.parent = &adapter->ccw_device->dev;
|
|
port->dev.groups = zfcp_port_attr_groups;
|
|
port->dev.release = zfcp_port_release;
|
|
|
|
if (dev_set_name(&port->dev, "0x%016llx", (unsigned long long)wwpn)) {
|
|
kfree(port);
|
|
goto err_out;
|
|
}
|
|
retval = -EINVAL;
|
|
|
|
if (device_register(&port->dev)) {
|
|
put_device(&port->dev);
|
|
goto err_out;
|
|
}
|
|
|
|
write_lock_irq(&adapter->port_list_lock);
|
|
list_add_tail(&port->list, &adapter->port_list);
|
|
write_unlock_irq(&adapter->port_list_lock);
|
|
|
|
atomic_set_mask(status | ZFCP_STATUS_COMMON_RUNNING, &port->status);
|
|
|
|
return port;
|
|
|
|
err_out:
|
|
zfcp_ccw_adapter_put(adapter);
|
|
return ERR_PTR(retval);
|
|
}
|
|
|
|
/**
|
|
* zfcp_sg_free_table - free memory used by scatterlists
|
|
* @sg: pointer to scatterlist
|
|
* @count: number of scatterlist which are to be free'ed
|
|
* the scatterlist are expected to reference pages always
|
|
*/
|
|
void zfcp_sg_free_table(struct scatterlist *sg, int count)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < count; i++, sg++)
|
|
if (sg)
|
|
free_page((unsigned long) sg_virt(sg));
|
|
else
|
|
break;
|
|
}
|
|
|
|
/**
|
|
* zfcp_sg_setup_table - init scatterlist and allocate, assign buffers
|
|
* @sg: pointer to struct scatterlist
|
|
* @count: number of scatterlists which should be assigned with buffers
|
|
* of size page
|
|
*
|
|
* Returns: 0 on success, -ENOMEM otherwise
|
|
*/
|
|
int zfcp_sg_setup_table(struct scatterlist *sg, int count)
|
|
{
|
|
void *addr;
|
|
int i;
|
|
|
|
sg_init_table(sg, count);
|
|
for (i = 0; i < count; i++, sg++) {
|
|
addr = (void *) get_zeroed_page(GFP_KERNEL);
|
|
if (!addr) {
|
|
zfcp_sg_free_table(sg, i);
|
|
return -ENOMEM;
|
|
}
|
|
sg_set_buf(sg, addr, PAGE_SIZE);
|
|
}
|
|
return 0;
|
|
}
|