On 9/5/13 5:45 AM, "Neil Horman" <[email protected]> wrote:

>On Wed, Sep 04, 2013 at 04:47:27PM -0700, Robert Love wrote:
>> 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.
>> 
>> Cc: Hiral Patel <[email protected]>
>> Signed-off-by: Robert Love <[email protected]>
>Acked-by: Neil Horman <[email protected]>
Tested-by: Hiral Patel <[email protected]>

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