linux/drivers/scsi/fcoe/fcoe_transport.c
Robert Love d85e607b34 [SCSI] libfcoe: Remove unnecessary module state checks
libfcoe's interface consists of create, destroy, enable,
disable and create_vn2vn. These are currently module
paramaters added durring the module initialization. A
concern arose that the module parameters were being added
with write permissions before the module had completed
initialization. The following code was added to each
sysfs store file.

* Make sure the module has been initialized, and is not about to be
* removed.  Module parameter sysfs files are writable before the
* module_init function is called and after module_exit.
*/
if (THIS_MODULE->state != MODULE_STATE_LIVE)
    goto out_nodev;

This check was called out as unhelpful as the module can
go dead at any time and therefore its state isn't a reliable
thing to look at as a sign of stability and initialization
completion. Also, that functional interfaces like these
should be added after module initialization.

This patch removes the unnecessary checks and hopes to
disprove the concern about initialization ordering.

Recent fcoe transport rework changes now require fcoe
transports to register with libfcoe before any operation
can take place. libfcoe may access some static variables
but nothing that could cause a problem. Once a fcoe transport
is registered, libfcoe is usable and any interface calls will
be functional.

Signed-off-by: Robert Love <robert.w.love@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: James Bottomley <jbottomley@parallels.com>
2011-05-24 12:37:35 -04:00

731 lines
18 KiB
C

/*
* Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
*
* Maintained at www.Open-FCoE.org
*/
#include <linux/types.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/errno.h>
#include <linux/crc32.h>
#include <scsi/libfcoe.h>
#include "libfcoe.h"
MODULE_AUTHOR("Open-FCoE.org");
MODULE_DESCRIPTION("FIP discovery protocol and FCoE transport for FCoE HBAs");
MODULE_LICENSE("GPL v2");
static int fcoe_transport_create(const char *, struct kernel_param *);
static int fcoe_transport_destroy(const char *, struct kernel_param *);
static int fcoe_transport_show(char *buffer, const struct kernel_param *kp);
static struct fcoe_transport *fcoe_transport_lookup(struct net_device *device);
static struct fcoe_transport *fcoe_netdev_map_lookup(struct net_device *device);
static int fcoe_transport_enable(const char *, struct kernel_param *);
static int fcoe_transport_disable(const char *, struct kernel_param *);
static int libfcoe_device_notification(struct notifier_block *notifier,
ulong event, void *ptr);
static LIST_HEAD(fcoe_transports);
static DEFINE_MUTEX(ft_mutex);
static LIST_HEAD(fcoe_netdevs);
static DEFINE_MUTEX(fn_mutex);
unsigned int libfcoe_debug_logging;
module_param_named(debug_logging, libfcoe_debug_logging, int, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(debug_logging, "a bit mask of logging levels");
module_param_call(show, NULL, fcoe_transport_show, NULL, S_IRUSR);
__MODULE_PARM_TYPE(show, "string");
MODULE_PARM_DESC(show, " Show attached FCoE transports");
module_param_call(create, fcoe_transport_create, NULL,
(void *)FIP_MODE_FABRIC, S_IWUSR);
__MODULE_PARM_TYPE(create, "string");
MODULE_PARM_DESC(create, " Creates fcoe instance on a ethernet interface");
module_param_call(create_vn2vn, fcoe_transport_create, NULL,
(void *)FIP_MODE_VN2VN, S_IWUSR);
__MODULE_PARM_TYPE(create_vn2vn, "string");
MODULE_PARM_DESC(create_vn2vn, " Creates a VN_node to VN_node FCoE instance "
"on an Ethernet interface");
module_param_call(destroy, fcoe_transport_destroy, NULL, NULL, S_IWUSR);
__MODULE_PARM_TYPE(destroy, "string");
MODULE_PARM_DESC(destroy, " Destroys fcoe instance on a ethernet interface");
module_param_call(enable, fcoe_transport_enable, NULL, NULL, S_IWUSR);
__MODULE_PARM_TYPE(enable, "string");
MODULE_PARM_DESC(enable, " Enables fcoe on a ethernet interface.");
module_param_call(disable, fcoe_transport_disable, NULL, NULL, S_IWUSR);
__MODULE_PARM_TYPE(disable, "string");
MODULE_PARM_DESC(disable, " Disables fcoe on a ethernet interface.");
/* notification function for packets from net device */
static struct notifier_block libfcoe_notifier = {
.notifier_call = libfcoe_device_notification,
};
/**
* fcoe_fc_crc() - Calculates the CRC for a given frame
* @fp: The frame to be checksumed
*
* This uses crc32() routine to calculate the CRC for a frame
*
* Return: The 32 bit CRC value
*/
u32 fcoe_fc_crc(struct fc_frame *fp)
{
struct sk_buff *skb = fp_skb(fp);
struct skb_frag_struct *frag;
unsigned char *data;
unsigned long off, len, clen;
u32 crc;
unsigned i;
crc = crc32(~0, skb->data, skb_headlen(skb));
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
frag = &skb_shinfo(skb)->frags[i];
off = frag->page_offset;
len = frag->size;
while (len > 0) {
clen = min(len, PAGE_SIZE - (off & ~PAGE_MASK));
data = kmap_atomic(frag->page + (off >> PAGE_SHIFT),
KM_SKB_DATA_SOFTIRQ);
crc = crc32(crc, data + (off & ~PAGE_MASK), clen);
kunmap_atomic(data, KM_SKB_DATA_SOFTIRQ);
off += clen;
len -= clen;
}
}
return crc;
}
EXPORT_SYMBOL_GPL(fcoe_fc_crc);
/**
* fcoe_start_io() - Start FCoE I/O
* @skb: The packet to be transmitted
*
* This routine is called from the net device to start transmitting
* FCoE packets.
*
* Returns: 0 for success
*/
int fcoe_start_io(struct sk_buff *skb)
{
struct sk_buff *nskb;
int rc;
nskb = skb_clone(skb, GFP_ATOMIC);
if (!nskb)
return -ENOMEM;
rc = dev_queue_xmit(nskb);
if (rc != 0)
return rc;
kfree_skb(skb);
return 0;
}
EXPORT_SYMBOL_GPL(fcoe_start_io);
/**
* fcoe_clean_pending_queue() - Dequeue a skb and free it
* @lport: The local port to dequeue a skb on
*/
void fcoe_clean_pending_queue(struct fc_lport *lport)
{
struct fcoe_port *port = lport_priv(lport);
struct sk_buff *skb;
spin_lock_bh(&port->fcoe_pending_queue.lock);
while ((skb = __skb_dequeue(&port->fcoe_pending_queue)) != NULL) {
spin_unlock_bh(&port->fcoe_pending_queue.lock);
kfree_skb(skb);
spin_lock_bh(&port->fcoe_pending_queue.lock);
}
spin_unlock_bh(&port->fcoe_pending_queue.lock);
}
EXPORT_SYMBOL_GPL(fcoe_clean_pending_queue);
/**
* fcoe_check_wait_queue() - Attempt to clear the transmit backlog
* @lport: The local port whose backlog is to be cleared
*
* This empties the wait_queue, dequeues the head of the wait_queue queue
* and calls fcoe_start_io() for each packet. If all skb have been
* transmitted it returns the qlen. If an error occurs it restores
* wait_queue (to try again later) and returns -1.
*
* The wait_queue is used when the skb transmit fails. The failed skb
* will go in the wait_queue which will be emptied by the timer function or
* by the next skb transmit.
*/
void fcoe_check_wait_queue(struct fc_lport *lport, struct sk_buff *skb)
{
struct fcoe_port *port = lport_priv(lport);
int rc;
spin_lock_bh(&port->fcoe_pending_queue.lock);
if (skb)
__skb_queue_tail(&port->fcoe_pending_queue, skb);
if (port->fcoe_pending_queue_active)
goto out;
port->fcoe_pending_queue_active = 1;
while (port->fcoe_pending_queue.qlen) {
/* keep qlen > 0 until fcoe_start_io succeeds */
port->fcoe_pending_queue.qlen++;
skb = __skb_dequeue(&port->fcoe_pending_queue);
spin_unlock_bh(&port->fcoe_pending_queue.lock);
rc = fcoe_start_io(skb);
spin_lock_bh(&port->fcoe_pending_queue.lock);
if (rc) {
__skb_queue_head(&port->fcoe_pending_queue, skb);
/* undo temporary increment above */
port->fcoe_pending_queue.qlen--;
break;
}
/* undo temporary increment above */
port->fcoe_pending_queue.qlen--;
}
if (port->fcoe_pending_queue.qlen < port->min_queue_depth)
lport->qfull = 0;
if (port->fcoe_pending_queue.qlen && !timer_pending(&port->timer))
mod_timer(&port->timer, jiffies + 2);
port->fcoe_pending_queue_active = 0;
out:
if (port->fcoe_pending_queue.qlen > port->max_queue_depth)
lport->qfull = 1;
spin_unlock_bh(&port->fcoe_pending_queue.lock);
}
EXPORT_SYMBOL_GPL(fcoe_check_wait_queue);
/**
* fcoe_queue_timer() - The fcoe queue timer
* @lport: The local port
*
* Calls fcoe_check_wait_queue on timeout
*/
void fcoe_queue_timer(ulong lport)
{
fcoe_check_wait_queue((struct fc_lport *)lport, NULL);
}
EXPORT_SYMBOL_GPL(fcoe_queue_timer);
/**
* fcoe_get_paged_crc_eof() - Allocate a page to be used for the trailer CRC
* @skb: The packet to be transmitted
* @tlen: The total length of the trailer
* @fps: The fcoe context
*
* This routine allocates a page for frame trailers. The page is re-used if
* there is enough room left on it for the current trailer. If there isn't
* enough buffer left a new page is allocated for the trailer. Reference to
* the page from this function as well as the skbs using the page fragments
* ensure that the page is freed at the appropriate time.
*
* Returns: 0 for success
*/
int fcoe_get_paged_crc_eof(struct sk_buff *skb, int tlen,
struct fcoe_percpu_s *fps)
{
struct page *page;
page = fps->crc_eof_page;
if (!page) {
page = alloc_page(GFP_ATOMIC);
if (!page)
return -ENOMEM;
fps->crc_eof_page = page;
fps->crc_eof_offset = 0;
}
get_page(page);
skb_fill_page_desc(skb, skb_shinfo(skb)->nr_frags, page,
fps->crc_eof_offset, tlen);
skb->len += tlen;
skb->data_len += tlen;
skb->truesize += tlen;
fps->crc_eof_offset += sizeof(struct fcoe_crc_eof);
if (fps->crc_eof_offset >= PAGE_SIZE) {
fps->crc_eof_page = NULL;
fps->crc_eof_offset = 0;
put_page(page);
}
return 0;
}
EXPORT_SYMBOL_GPL(fcoe_get_paged_crc_eof);
/**
* fcoe_transport_lookup - find an fcoe transport that matches a netdev
* @netdev: The netdev to look for from all attached transports
*
* Returns : ptr to the fcoe transport that supports this netdev or NULL
* if not found.
*
* The ft_mutex should be held when this is called
*/
static struct fcoe_transport *fcoe_transport_lookup(struct net_device *netdev)
{
struct fcoe_transport *ft = NULL;
list_for_each_entry(ft, &fcoe_transports, list)
if (ft->match && ft->match(netdev))
return ft;
return NULL;
}
/**
* fcoe_transport_attach - Attaches an FCoE transport
* @ft: The fcoe transport to be attached
*
* Returns : 0 for success
*/
int fcoe_transport_attach(struct fcoe_transport *ft)
{
int rc = 0;
mutex_lock(&ft_mutex);
if (ft->attached) {
LIBFCOE_TRANSPORT_DBG("transport %s already attached\n",
ft->name);
rc = -EEXIST;
goto out_attach;
}
/* Add default transport to the tail */
if (strcmp(ft->name, FCOE_TRANSPORT_DEFAULT))
list_add(&ft->list, &fcoe_transports);
else
list_add_tail(&ft->list, &fcoe_transports);
ft->attached = true;
LIBFCOE_TRANSPORT_DBG("attaching transport %s\n", ft->name);
out_attach:
mutex_unlock(&ft_mutex);
return rc;
}
EXPORT_SYMBOL(fcoe_transport_attach);
/**
* fcoe_transport_detach - Detaches an FCoE transport
* @ft: The fcoe transport to be attached
*
* Returns : 0 for success
*/
int fcoe_transport_detach(struct fcoe_transport *ft)
{
int rc = 0;
struct fcoe_netdev_mapping *nm = NULL, *tmp;
mutex_lock(&ft_mutex);
if (!ft->attached) {
LIBFCOE_TRANSPORT_DBG("transport %s already detached\n",
ft->name);
rc = -ENODEV;
goto out_attach;
}
/* remove netdev mapping for this transport as it is going away */
mutex_lock(&fn_mutex);
list_for_each_entry_safe(nm, tmp, &fcoe_netdevs, list) {
if (nm->ft == ft) {
LIBFCOE_TRANSPORT_DBG("transport %s going away, "
"remove its netdev mapping for %s\n",
ft->name, nm->netdev->name);
list_del(&nm->list);
kfree(nm);
}
}
mutex_unlock(&fn_mutex);
list_del(&ft->list);
ft->attached = false;
LIBFCOE_TRANSPORT_DBG("detaching transport %s\n", ft->name);
out_attach:
mutex_unlock(&ft_mutex);
return rc;
}
EXPORT_SYMBOL(fcoe_transport_detach);
static int fcoe_transport_show(char *buffer, const struct kernel_param *kp)
{
int i, j;
struct fcoe_transport *ft = NULL;
i = j = sprintf(buffer, "Attached FCoE transports:");
mutex_lock(&ft_mutex);
list_for_each_entry(ft, &fcoe_transports, list) {
if (i >= PAGE_SIZE - IFNAMSIZ)
break;
i += snprintf(&buffer[i], IFNAMSIZ, "%s ", ft->name);
}
mutex_unlock(&ft_mutex);
if (i == j)
i += snprintf(&buffer[i], IFNAMSIZ, "none");
return i;
}
static int __init fcoe_transport_init(void)
{
register_netdevice_notifier(&libfcoe_notifier);
return 0;
}
static int __exit fcoe_transport_exit(void)
{
struct fcoe_transport *ft;
unregister_netdevice_notifier(&libfcoe_notifier);
mutex_lock(&ft_mutex);
list_for_each_entry(ft, &fcoe_transports, list)
printk(KERN_ERR "FCoE transport %s is still attached!\n",
ft->name);
mutex_unlock(&ft_mutex);
return 0;
}
static int fcoe_add_netdev_mapping(struct net_device *netdev,
struct fcoe_transport *ft)
{
struct fcoe_netdev_mapping *nm;
nm = kmalloc(sizeof(*nm), GFP_KERNEL);
if (!nm) {
printk(KERN_ERR "Unable to allocate netdev_mapping");
return -ENOMEM;
}
nm->netdev = netdev;
nm->ft = ft;
mutex_lock(&fn_mutex);
list_add(&nm->list, &fcoe_netdevs);
mutex_unlock(&fn_mutex);
return 0;
}
static void fcoe_del_netdev_mapping(struct net_device *netdev)
{
struct fcoe_netdev_mapping *nm = NULL, *tmp;
mutex_lock(&fn_mutex);
list_for_each_entry_safe(nm, tmp, &fcoe_netdevs, list) {
if (nm->netdev == netdev) {
list_del(&nm->list);
kfree(nm);
mutex_unlock(&fn_mutex);
return;
}
}
mutex_unlock(&fn_mutex);
}
/**
* fcoe_netdev_map_lookup - find the fcoe transport that matches the netdev on which
* it was created
*
* Returns : ptr to the fcoe transport that supports this netdev or NULL
* if not found.
*
* The ft_mutex should be held when this is called
*/
static struct fcoe_transport *fcoe_netdev_map_lookup(struct net_device *netdev)
{
struct fcoe_transport *ft = NULL;
struct fcoe_netdev_mapping *nm;
mutex_lock(&fn_mutex);
list_for_each_entry(nm, &fcoe_netdevs, list) {
if (netdev == nm->netdev) {
ft = nm->ft;
mutex_unlock(&fn_mutex);
return ft;
}
}
mutex_unlock(&fn_mutex);
return NULL;
}
/**
* fcoe_if_to_netdev() - Parse a name buffer to get a net device
* @buffer: The name of the net device
*
* Returns: NULL or a ptr to net_device
*/
static struct net_device *fcoe_if_to_netdev(const char *buffer)
{
char *cp;
char ifname[IFNAMSIZ + 2];
if (buffer) {
strlcpy(ifname, buffer, IFNAMSIZ);
cp = ifname + strlen(ifname);
while (--cp >= ifname && *cp == '\n')
*cp = '\0';
return dev_get_by_name(&init_net, ifname);
}
return NULL;
}
/**
* libfcoe_device_notification() - Handler for net device events
* @notifier: The context of the notification
* @event: The type of event
* @ptr: The net device that the event was on
*
* This function is called by the Ethernet driver in case of link change event.
*
* Returns: 0 for success
*/
static int libfcoe_device_notification(struct notifier_block *notifier,
ulong event, void *ptr)
{
struct net_device *netdev = ptr;
switch (event) {
case NETDEV_UNREGISTER:
printk(KERN_ERR "libfcoe_device_notification: NETDEV_UNREGISTER %s\n",
netdev->name);
fcoe_del_netdev_mapping(netdev);
break;
}
return NOTIFY_OK;
}
/**
* fcoe_transport_create() - Create a fcoe interface
* @buffer: The name of the Ethernet interface to create on
* @kp: The associated kernel param
*
* Called from sysfs. This holds the ft_mutex while calling the
* registered fcoe transport's create function.
*
* Returns: 0 for success
*/
static int fcoe_transport_create(const char *buffer, struct kernel_param *kp)
{
int rc = -ENODEV;
struct net_device *netdev = NULL;
struct fcoe_transport *ft = NULL;
enum fip_state fip_mode = (enum fip_state)(long)kp->arg;
mutex_lock(&ft_mutex);
netdev = fcoe_if_to_netdev(buffer);
if (!netdev) {
LIBFCOE_TRANSPORT_DBG("Invalid device %s.\n", buffer);
goto out_nodev;
}
ft = fcoe_netdev_map_lookup(netdev);
if (ft) {
LIBFCOE_TRANSPORT_DBG("transport %s already has existing "
"FCoE instance on %s.\n",
ft->name, netdev->name);
rc = -EEXIST;
goto out_putdev;
}
ft = fcoe_transport_lookup(netdev);
if (!ft) {
LIBFCOE_TRANSPORT_DBG("no FCoE transport found for %s.\n",
netdev->name);
goto out_putdev;
}
rc = fcoe_add_netdev_mapping(netdev, ft);
if (rc) {
LIBFCOE_TRANSPORT_DBG("failed to add new netdev mapping "
"for FCoE transport %s for %s.\n",
ft->name, netdev->name);
goto out_putdev;
}
/* pass to transport create */
rc = ft->create ? ft->create(netdev, fip_mode) : -ENODEV;
if (rc)
fcoe_del_netdev_mapping(netdev);
LIBFCOE_TRANSPORT_DBG("transport %s %s to create fcoe on %s.\n",
ft->name, (rc) ? "failed" : "succeeded",
netdev->name);
out_putdev:
dev_put(netdev);
out_nodev:
mutex_unlock(&ft_mutex);
return rc;
}
/**
* fcoe_transport_destroy() - Destroy a FCoE interface
* @buffer: The name of the Ethernet interface to be destroyed
* @kp: The associated kernel parameter
*
* Called from sysfs. This holds the ft_mutex while calling the
* registered fcoe transport's destroy function.
*
* Returns: 0 for success
*/
static int fcoe_transport_destroy(const char *buffer, struct kernel_param *kp)
{
int rc = -ENODEV;
struct net_device *netdev = NULL;
struct fcoe_transport *ft = NULL;
mutex_lock(&ft_mutex);
netdev = fcoe_if_to_netdev(buffer);
if (!netdev) {
LIBFCOE_TRANSPORT_DBG("invalid device %s.\n", buffer);
goto out_nodev;
}
ft = fcoe_netdev_map_lookup(netdev);
if (!ft) {
LIBFCOE_TRANSPORT_DBG("no FCoE transport found for %s.\n",
netdev->name);
goto out_putdev;
}
/* pass to transport destroy */
rc = ft->destroy ? ft->destroy(netdev) : -ENODEV;
fcoe_del_netdev_mapping(netdev);
LIBFCOE_TRANSPORT_DBG("transport %s %s to destroy fcoe on %s.\n",
ft->name, (rc) ? "failed" : "succeeded",
netdev->name);
out_putdev:
dev_put(netdev);
out_nodev:
mutex_unlock(&ft_mutex);
return rc;
}
/**
* fcoe_transport_disable() - Disables a FCoE interface
* @buffer: The name of the Ethernet interface to be disabled
* @kp: The associated kernel parameter
*
* Called from sysfs.
*
* Returns: 0 for success
*/
static int fcoe_transport_disable(const char *buffer, struct kernel_param *kp)
{
int rc = -ENODEV;
struct net_device *netdev = NULL;
struct fcoe_transport *ft = NULL;
mutex_lock(&ft_mutex);
netdev = fcoe_if_to_netdev(buffer);
if (!netdev)
goto out_nodev;
ft = fcoe_netdev_map_lookup(netdev);
if (!ft)
goto out_putdev;
rc = ft->disable ? ft->disable(netdev) : -ENODEV;
out_putdev:
dev_put(netdev);
out_nodev:
mutex_unlock(&ft_mutex);
if (rc == -ERESTARTSYS)
return restart_syscall();
else
return rc;
}
/**
* fcoe_transport_enable() - Enables a FCoE interface
* @buffer: The name of the Ethernet interface to be enabled
* @kp: The associated kernel parameter
*
* Called from sysfs.
*
* Returns: 0 for success
*/
static int fcoe_transport_enable(const char *buffer, struct kernel_param *kp)
{
int rc = -ENODEV;
struct net_device *netdev = NULL;
struct fcoe_transport *ft = NULL;
mutex_lock(&ft_mutex);
netdev = fcoe_if_to_netdev(buffer);
if (!netdev)
goto out_nodev;
ft = fcoe_netdev_map_lookup(netdev);
if (!ft)
goto out_putdev;
rc = ft->enable ? ft->enable(netdev) : -ENODEV;
out_putdev:
dev_put(netdev);
out_nodev:
mutex_unlock(&ft_mutex);
return rc;
}
/**
* libfcoe_init() - Initialization routine for libfcoe.ko
*/
static int __init libfcoe_init(void)
{
fcoe_transport_init();
return 0;
}
module_init(libfcoe_init);
/**
* libfcoe_exit() - Tear down libfcoe.ko
*/
static void __exit libfcoe_exit(void)
{
fcoe_transport_exit();
}
module_exit(libfcoe_exit);