Commit 9d34876f authored by Robert Love's avatar Robert Love

libfcoe: Make fcoe_sysfs optional / fix fnic NULL exception

fnic doesn't use any of the create/destroy/enable/disable interfaces
either from the (legacy) module paramaters or the (new) fcoe_sysfs
interfaces. When fcoe_sysfs was introduced fnic wasn't changed since
it wasn't using the interfaces. libfcoe incorrectly assumed that that
all of its users were using fcoe_sysfs and when adding and deleting
FCFs would assume the existance of a fcoe_ctlr_device. fnic was not
allocating this structure because it doesn't care about the standard
user interfaces (fnic starts on link only). If/When libfcoe tried to use
the fcoe_ctlr_device's lock for the first time a NULL pointer exception
would be triggered.

Since fnic doesn't care about sysfs or user interfaces, the solution
is to drop libfcoe's assumption that all drivers are using fcoe_sysfs.

This patch accomplishes this by changing some of the structure
relationships.

We need a way to determine when a LLD is using fcoe_sysfs or not and
we can do that by checking for the existance of the fcoe_ctlr_device.
Prior to this patch, it was assumed that the fcoe_ctlr structure was
allocated with the fcoe_ctlr_device and immediately followed it in
memory. To reach the fcoe_ctlr_device we would simply go back in memory
from the fcoe_ctlr to get the fcoe_ctlr_device.

Since fnic doesn't allocate the fcoe_ctlr_device, we cannot keep that
assumption. This patch adds a pointer from the fcoe_ctlr to the
fcoe_ctlr_device. For bnx2fc and fcoe we will continue to allocate the
two structures together, but then we'll set the ctlr->cdev pointer
to point at the fcoe_ctlr_device. fnic will not change and will continue
to allocate the fcoe_ctlr itself, and ctlr->cdev will remain NULL.

When libfcoe adds fcoe_fcf's to the fcoe_ctlr it will check if ctlr->cdev
is set and only if so will it continue to interact with fcoe_sysfs.
Signed-off-by: default avatarRobert Love <robert.w.love@intel.com>
Acked-by: default avatarNeil Horman <nhorman@tuxdriver.com>
Tested-by: default avatarHiral Patel <hiralpat@cisco.com>
parent 1c2c1b4f
......@@ -1381,6 +1381,7 @@ struct bnx2fc_interface *bnx2fc_interface_create(struct bnx2fc_hba *hba,
return NULL;
}
ctlr = fcoe_ctlr_device_priv(ctlr_dev);
ctlr->cdev = ctlr_dev;
interface = fcoe_ctlr_priv(ctlr);
dev_hold(netdev);
kref_init(&interface->kref);
......
......@@ -408,6 +408,7 @@ static struct fcoe_interface *fcoe_interface_create(struct net_device *netdev,
}
ctlr = fcoe_ctlr_device_priv(ctlr_dev);
ctlr->cdev = ctlr_dev;
fcoe = fcoe_ctlr_priv(ctlr);
dev_hold(netdev);
......
......@@ -160,10 +160,16 @@ void fcoe_ctlr_init(struct fcoe_ctlr *fip, enum fip_state mode)
}
EXPORT_SYMBOL(fcoe_ctlr_init);
/**
* fcoe_sysfs_fcf_add() - Add a fcoe_fcf{,_device} to a fcoe_ctlr{,_device}
* @new: The newly discovered FCF
*
* Called with fip->ctlr_mutex held
*/
static int fcoe_sysfs_fcf_add(struct fcoe_fcf *new)
{
struct fcoe_ctlr *fip = new->fip;
struct fcoe_ctlr_device *ctlr_dev = fcoe_ctlr_to_ctlr_dev(fip);
struct fcoe_ctlr_device *ctlr_dev;
struct fcoe_fcf_device *temp, *fcf_dev;
int rc = -ENOMEM;
......@@ -174,8 +180,6 @@ static int fcoe_sysfs_fcf_add(struct fcoe_fcf *new)
if (!temp)
goto out;
mutex_lock(&ctlr_dev->lock);
temp->fabric_name = new->fabric_name;
temp->switch_name = new->switch_name;
temp->fc_map = new->fc_map;
......@@ -185,55 +189,83 @@ static int fcoe_sysfs_fcf_add(struct fcoe_fcf *new)
temp->fka_period = new->fka_period;
temp->selected = 0; /* default to unselected */
fcf_dev = fcoe_fcf_device_add(ctlr_dev, temp);
if (unlikely(!fcf_dev))
goto unlock;
/*
* The fcoe_sysfs layer can return a CONNECTED fcf that
* has a priv (fcf was never deleted) or a CONNECTED fcf
* that doesn't have a priv (fcf was deleted). However,
* libfcoe will always delete FCFs before trying to add
* them. This is ensured because both recv_adv and
* age_fcfs are protected by the the fcoe_ctlr's mutex.
* This means that we should never get a FCF with a
* non-NULL priv pointer.
* If ctlr_dev doesn't exist then it means we're a libfcoe user
* who doesn't use fcoe_syfs and didn't allocate a fcoe_ctlr_device.
* fnic would be an example of a driver with this behavior. In this
* case we want to add the fcoe_fcf to the fcoe_ctlr list, but we
* don't want to make sysfs changes.
*/
BUG_ON(fcf_dev->priv);
fcf_dev->priv = new;
new->fcf_dev = fcf_dev;
ctlr_dev = fcoe_ctlr_to_ctlr_dev(fip);
if (ctlr_dev) {
mutex_lock(&ctlr_dev->lock);
fcf_dev = fcoe_fcf_device_add(ctlr_dev, temp);
if (unlikely(!fcf_dev)) {
rc = -ENOMEM;
goto out;
}
/*
* The fcoe_sysfs layer can return a CONNECTED fcf that
* has a priv (fcf was never deleted) or a CONNECTED fcf
* that doesn't have a priv (fcf was deleted). However,
* libfcoe will always delete FCFs before trying to add
* them. This is ensured because both recv_adv and
* age_fcfs are protected by the the fcoe_ctlr's mutex.
* This means that we should never get a FCF with a
* non-NULL priv pointer.
*/
BUG_ON(fcf_dev->priv);
fcf_dev->priv = new;
new->fcf_dev = fcf_dev;
mutex_unlock(&ctlr_dev->lock);
}
list_add(&new->list, &fip->fcfs);
fip->fcf_count++;
rc = 0;
unlock:
mutex_unlock(&ctlr_dev->lock);
out:
kfree(temp);
return rc;
}
/**
* fcoe_sysfs_fcf_del() - Remove a fcoe_fcf{,_device} to a fcoe_ctlr{,_device}
* @new: The FCF to be removed
*
* Called with fip->ctlr_mutex held
*/
static void fcoe_sysfs_fcf_del(struct fcoe_fcf *new)
{
struct fcoe_ctlr *fip = new->fip;
struct fcoe_ctlr_device *ctlr_dev = fcoe_ctlr_to_ctlr_dev(fip);
struct fcoe_ctlr_device *cdev;
struct fcoe_fcf_device *fcf_dev;
list_del(&new->list);
fip->fcf_count--;
mutex_lock(&ctlr_dev->lock);
fcf_dev = fcoe_fcf_to_fcf_dev(new);
WARN_ON(!fcf_dev);
new->fcf_dev = NULL;
fcoe_fcf_device_delete(fcf_dev);
kfree(new);
mutex_unlock(&ctlr_dev->lock);
/*
* If ctlr_dev doesn't exist then it means we're a libfcoe user
* who doesn't use fcoe_syfs and didn't allocate a fcoe_ctlr_device
* or a fcoe_fcf_device.
*
* fnic would be an example of a driver with this behavior. In this
* case we want to remove the fcoe_fcf from the fcoe_ctlr list (above),
* but we don't want to make sysfs changes.
*/
cdev = fcoe_ctlr_to_ctlr_dev(fip);
if (cdev) {
mutex_lock(&cdev->lock);
fcf_dev = fcoe_fcf_to_fcf_dev(new);
WARN_ON(!fcf_dev);
new->fcf_dev = NULL;
fcoe_fcf_device_delete(fcf_dev);
kfree(new);
mutex_unlock(&cdev->lock);
}
}
/**
......
......@@ -90,6 +90,7 @@ enum fip_state {
* @lp: &fc_lport: libfc local port.
* @sel_fcf: currently selected FCF, or NULL.
* @fcfs: list of discovered FCFs.
* @cdev: (Optional) pointer to sysfs fcoe_ctlr_device.
* @fcf_count: number of discovered FCF entries.
* @sol_time: time when a multicast solicitation was last sent.
* @sel_time: time after which to select an FCF.
......@@ -127,6 +128,7 @@ struct fcoe_ctlr {
struct fc_lport *lp;
struct fcoe_fcf *sel_fcf;
struct list_head fcfs;
struct fcoe_ctlr_device *cdev;
u16 fcf_count;
unsigned long sol_time;
unsigned long sel_time;
......@@ -168,8 +170,11 @@ static inline void *fcoe_ctlr_priv(const struct fcoe_ctlr *ctlr)
return (void *)(ctlr + 1);
}
/*
* This assumes that the fcoe_ctlr (x) is allocated with the fcoe_ctlr_device.
*/
#define fcoe_ctlr_to_ctlr_dev(x) \
(struct fcoe_ctlr_device *)(((struct fcoe_ctlr_device *)(x)) - 1)
(x)->cdev
/**
* struct fcoe_fcf - Fibre-Channel Forwarder
......
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