[PATCH linux dev-4.13 11/16] hwmon (p9_sbe): Add static key to satisfy lockdep

[Eddie James]

On 02/19/2018 10:18 PM, Andrew Jeffery wrote:
> Previously we received the following warning:

Acked-by: Eddie James <eajames at linux.vnet.ibm.com>

>
> [    7.221161] INFO: trying to register non-static key.
> [    7.226163] the code is fine but needs lockdep annotation.
> [    7.231650] turning off the locking correctness validator.
> [    7.237152] CPU: 0 PID: 1 Comm: swapper Tainted: G        W       4.13.16-00190-g78a200cb21ab #2393
> [    7.246194] Hardware name: Generic DT based system
> [    7.251040] [<8001141c>] (unwind_backtrace) from [<8000e87c>] (show_stack+0x20/0x24)
> [    7.258827] [<8000e87c>] (show_stack) from [<804a65ec>] (dump_stack+0x20/0x28)
> [    7.266098] [<804a65ec>] (dump_stack) from [<80054b08>] (register_lock_class+0x270/0x614)
> [    7.274308] [<80054b08>] (register_lock_class) from [<800589f0>] (__lock_acquire+0x7c/0x17f4)
> [    7.282857] [<800589f0>] (__lock_acquire) from [<8005ac18>] (lock_acquire+0xd8/0x204)
> [    7.290719] [<8005ac18>] (lock_acquire) from [<804c0dcc>] (_raw_spin_lock_irqsave+0x60/0x74)
> [    7.299200] [<804c0dcc>] (_raw_spin_lock_irqsave) from [<8035ecc0>] (p9_sbe_occ_send_cmd+0x30/0x100)
> [    7.308363] [<8035ecc0>] (p9_sbe_occ_send_cmd) from [<8035c9ac>] (occ_poll+0x60/0x210)
> [    7.316309] [<8035c9ac>] (occ_poll) from [<8035d9c8>] (occ_setup+0x50/0x1260)
> [    7.323475] [<8035d9c8>] (occ_setup) from [<8035edf0>] (p9_sbe_occ_probe+0x60/0x7c)
> [    7.331167] [<8035edf0>] (p9_sbe_occ_probe) from [<802b97c8>] (platform_drv_probe+0x60/0xbc)
> [    7.339629] [<802b97c8>] (platform_drv_probe) from [<802b78f0>] (driver_probe_device+0x2e4/0x450)
> [    7.348516] [<802b78f0>] (driver_probe_device) from [<802b7c0c>] (__device_attach_driver+0xa4/0x10c)
> [    7.357668] [<802b7c0c>] (__device_attach_driver) from [<802b5de0>] (bus_for_each_drv+0x54/0xa4)
> [    7.366477] [<802b5de0>] (bus_for_each_drv) from [<802b7454>] (__device_attach+0xc0/0x148)
> [    7.374758] [<802b7454>] (__device_attach) from [<802b7cd8>] (device_initial_probe+0x1c/0x20)
> [    7.383301] [<802b7cd8>] (device_initial_probe) from [<802b5ff8>] (bus_probe_device+0x98/0xa0)
> [    7.391943] [<802b5ff8>] (bus_probe_device) from [<802b426c>] (device_add+0x398/0x5c4)
> [    7.399895] [<802b426c>] (device_add) from [<8037ab10>] (of_device_add+0x40/0x48)
> [    7.407405] [<8037ab10>] (of_device_add) from [<8037b618>] (of_platform_device_create_pdata+0x88/0xc8)
> [    7.416735] [<8037b618>] (of_platform_device_create_pdata) from [<8037b94c>] (of_platform_device_create+0x20/0x24)
> [    7.427109] [<8037b94c>] (of_platform_device_create) from [<80394894>] (occ_probe+0x19c/0x238)
> [    7.435746] [<80394894>] (occ_probe) from [<802b97c8>] (platform_drv_probe+0x60/0xbc)
> [    7.443604] [<802b97c8>] (platform_drv_probe) from [<802b78f0>] (driver_probe_device+0x2e4/0x450)
> [    7.452497] [<802b78f0>] (driver_probe_device) from [<802b7b28>] (__driver_attach+0xcc/0x10c)
> [    7.461044] [<802b7b28>] (__driver_attach) from [<802b58a4>] (bus_for_each_dev+0x5c/0xac)
> [    7.469240] [<802b58a4>] (bus_for_each_dev) from [<802b7d04>] (driver_attach+0x28/0x30)
> [    7.477258] [<802b7d04>] (driver_attach) from [<802b62dc>] (bus_add_driver+0x194/0x254)
> [    7.485284] [<802b62dc>] (bus_add_driver) from [<802b8b54>] (driver_register+0x88/0x104)
> [    7.493398] [<802b8b54>] (driver_register) from [<802ba42c>] (__platform_driver_register+0x3c/0x50)
> [    7.502469] [<802ba42c>] (__platform_driver_register) from [<803943f0>] (occ_init+0x58/0x80)
> [    7.510945] [<803943f0>] (occ_init) from [<80669f1c>] (do_one_initcall+0xb0/0x170)
> [    7.518545] [<80669f1c>] (do_one_initcall) from [<8066a0f4>] (kernel_init_freeable+0x118/0x1d0)
> [    7.527280] [<8066a0f4>] (kernel_init_freeable) from [<804b9b94>] (kernel_init+0x18/0x104)
> [    7.535579] [<804b9b94>] (kernel_init) from [<8000a868>] (ret_from_fork+0x14/0x2c)
>
> Provide a static key to lockdep to help with this dynamically allocated mutex.
>
> Signed-off-by: Andrew Jeffery <andrew at aj.id.au>
> ---
>   drivers/hwmon/occ/p9_sbe.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/hwmon/occ/p9_sbe.c b/drivers/hwmon/occ/p9_sbe.c
> index 38cf57ad1bb8..b84cb1733fdf 100644
> --- a/drivers/hwmon/occ/p9_sbe.c
> +++ b/drivers/hwmon/occ/p9_sbe.c
> @@ -16,6 +16,9 @@
>
>   #include "common.h"
>
> +/* Satisfy lockdep's need for static keys */
> +static struct lock_class_key p9_sbe_occ_client_lock_key;
> +
>   struct p9_sbe_occ {
>   	struct occ occ;
>   	struct device *sbe;
> @@ -114,6 +117,7 @@ static int p9_sbe_occ_probe(struct platform_device *pdev)
>   		return -ENOMEM;
>
>   	mutex_init(&ctx->client_lock);
> +	lockdep_set_class(&ctx->client_lock, &p9_sbe_occ_client_lock_key);
>   	ctx->sbe = pdev->dev.parent;
>   	occ = &ctx->occ;
>   	occ->bus_dev = &pdev->dev;