On 6/24/19 2:28 PM, Hook, Gary wrote:
> Provide the ability to constrain the total number of enabled devices in
> the system. Once maxdev devices have been configured, additional
> devices are ignored.
>
> Signed-off-by: Gary R Hook <gary.hook@xxxxxxx>
> ---
> drivers/crypto/ccp/sp-pci.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/drivers/crypto/ccp/sp-pci.c b/drivers/crypto/ccp/sp-pci.c
> index c167c4671f45..b81493810689 100644
> --- a/drivers/crypto/ccp/sp-pci.c
> +++ b/drivers/crypto/ccp/sp-pci.c
> @@ -36,6 +36,13 @@
> /*
> * Limit CCP use to a specifed number of queues per device.
> */
> +
> +static struct mutex devcount_mutex ____cacheline_aligned;
I don't think I'd worry about the cache alignment since this is only
used at module load.
> +static unsigned int devcount = 0;
> +static unsigned int maxdev = 0;
> +module_param(maxdev, uint, 0444);
> +MODULE_PARM_DESC(maxdev, "Total number of devices to register");
> +
> static unsigned int nqueues = MAX_HW_QUEUES;
> module_param(nqueues, uint, 0444);
> MODULE_PARM_DESC(nqueues, "Number of queues per CCP (default: 5)");
> @@ -193,6 +200,9 @@ static int sp_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> int bar_mask;
> int ret;
>
> + if (maxdev && (devcount >= maxdev)) /* Too many devices? */
> + return 0;
> +
You need the mutex to protect the use of devcount. You could use an
atomic instead of the int/mutex combination.
And this will mess with the PSP support. It should be in the CCP
specific files, not here.
> ret = -ENOMEM;
> sp = sp_alloc_struct(dev);
> if (!sp)
> @@ -261,6 +271,11 @@ static int sp_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> if (ret)
> goto e_err;
>
> + /* Increase count of devices */
> + mutex_lock(&devcount_mutex);
> + devcount++;
> + mutex_unlock(&devcount_mutex);
> +
> return 0;
>
> e_err:
> @@ -374,6 +389,7 @@ static struct pci_driver sp_pci_driver = {
>
> int sp_pci_init(void)
> {
> + mutex_init(&devcount_mutex);
Tab instead of spaces.
Thanks,
Tom
> return pci_register_driver(&sp_pci_driver);
> }
>
>
