2019-03-22 14:27:54

by Arnd Bergmann

[permalink] [raw]
Subject: [PATCH] scsi: lpfc: avoid uninitialized variable warning

clang -Wuninitialized incorrectly sees a variable being used without
initialization:

drivers/scsi/lpfc/lpfc_nvme.c:2102:37: error: variable 'localport' is uninitialized when used here
[-Werror,-Wuninitialized]
lport = (struct lpfc_nvme_lport *)localport->private;
^~~~~~~~~
drivers/scsi/lpfc/lpfc_nvme.c:2059:38: note: initialize the variable 'localport' to silence this warning
struct nvme_fc_local_port *localport;
^
= NULL
1 error generated.

This is clearly in dead code, as the condition leading up to it is
always false when CONFIG_NVME_FC is disabled, and the variable
is always initialized when nvme_fc_register_localport() got
called successfully.

Change the preprocessor conditional to the equivalent C construct,
which makes the code more readable and gets rid of the warning.

Signed-off-by: Arnd Bergmann <[email protected]>
---
drivers/scsi/lpfc/lpfc_nvme.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/lpfc/lpfc_nvme.c b/drivers/scsi/lpfc/lpfc_nvme.c
index 1aa00d2c3f74..9defff711884 100644
--- a/drivers/scsi/lpfc/lpfc_nvme.c
+++ b/drivers/scsi/lpfc/lpfc_nvme.c
@@ -2080,15 +2080,15 @@ lpfc_nvme_create_localport(struct lpfc_vport *vport)
lpfc_nvme_template.max_hw_queues =
phba->sli4_hba.num_present_cpu;

+ if (!IS_ENABLED(CONFIG_NVME_FC))
+ return ret;
+
/* localport is allocated from the stack, but the registration
* call allocates heap memory as well as the private area.
*/
-#if (IS_ENABLED(CONFIG_NVME_FC))
+
ret = nvme_fc_register_localport(&nfcp_info, &lpfc_nvme_template,
&vport->phba->pcidev->dev, &localport);
-#else
- ret = -ENOMEM;
-#endif
if (!ret) {
lpfc_printf_vlog(vport, KERN_INFO, LOG_NVME | LOG_NVME_DISC,
"6005 Successfully registered local "
--
2.20.0



2019-03-22 16:48:29

by James Smart

[permalink] [raw]
Subject: Re: [PATCH] scsi: lpfc: avoid uninitialized variable warning

On 3/22/2019 7:25 AM, Arnd Bergmann wrote:
> clang -Wuninitialized incorrectly sees a variable being used without
> initialization:
>
> drivers/scsi/lpfc/lpfc_nvme.c:2102:37: error: variable 'localport' is uninitialized when used here
> [-Werror,-Wuninitialized]
> lport = (struct lpfc_nvme_lport *)localport->private;
> ^~~~~~~~~
> drivers/scsi/lpfc/lpfc_nvme.c:2059:38: note: initialize the variable 'localport' to silence this warning
> struct nvme_fc_local_port *localport;
> ^
> = NULL
> 1 error generated.
>
> This is clearly in dead code, as the condition leading up to it is
> always false when CONFIG_NVME_FC is disabled, and the variable
> is always initialized when nvme_fc_register_localport() got
> called successfully.
>
> Change the preprocessor conditional to the equivalent C construct,
> which makes the code more readable and gets rid of the warning.
>
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> drivers/scsi/lpfc/lpfc_nvme.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/scsi/lpfc/lpfc_nvme.c b/drivers/scsi/lpfc/lpfc_nvme.c
> index 1aa00d2c3f74..9defff711884 100644
> --- a/drivers/scsi/lpfc/lpfc_nvme.c
> +++ b/drivers/scsi/lpfc/lpfc_nvme.c
> @@ -2080,15 +2080,15 @@ lpfc_nvme_create_localport(struct lpfc_vport *vport)
> lpfc_nvme_template.max_hw_queues =
> phba->sli4_hba.num_present_cpu;
>
> + if (!IS_ENABLED(CONFIG_NVME_FC))
> + return ret;
> +
> /* localport is allocated from the stack, but the registration
> * call allocates heap memory as well as the private area.
> */
> -#if (IS_ENABLED(CONFIG_NVME_FC))
> +
> ret = nvme_fc_register_localport(&nfcp_info, &lpfc_nvme_template,
> &vport->phba->pcidev->dev, &localport);
> -#else
> - ret = -ENOMEM;
> -#endif
> if (!ret) {
> lpfc_printf_vlog(vport, KERN_INFO, LOG_NVME | LOG_NVME_DISC,
> "6005 Successfully registered local "

Looks good

Reviewed-By: James Smart <[email protected]>

-- james


2019-03-26 02:19:15

by Martin K. Petersen

[permalink] [raw]
Subject: Re: [PATCH] scsi: lpfc: avoid uninitialized variable warning


Arnd,

> clang -Wuninitialized incorrectly sees a variable being used without
> initialization:
>
> drivers/scsi/lpfc/lpfc_nvme.c:2102:37: error: variable 'localport' is uninitialized when used here
> [-Werror,-Wuninitialized]
> lport = (struct lpfc_nvme_lport *)localport->private;
> ^~~~~~~~~
> drivers/scsi/lpfc/lpfc_nvme.c:2059:38: note: initialize the variable 'localport' to silence this warning
> struct nvme_fc_local_port *localport;
> ^
> = NULL
> 1 error generated.

Applied to 5.2/scsi-queue, thanks!

--
Martin K. Petersen Oracle Linux Engineering