[lvc-project] [PATCH v2] scsi/cxgbi/libcxgbi: make sure sg is present before calling sg_next()

[Daniil Tatianin]

On 11/15/22 7:59 PM, Mike Christie wrote:
> Cc'ing the cxgbi/t maintainer, Varun.
> 
> On 11/15/22 2:17 AM, Daniil Tatianin wrote:
>> On 11/15/22 1:23 AM, Mike Christie wrote:
>>> On 11/14/22 9:09 AM, Daniil Tatianin wrote:
>>>> sg_next() dereferences the passed sg, therefore we have to verify that
>>>> it's present before calling it.
>>>>
>>>> Found by Linux Verification Center (linuxtesting.org) with the SVACE
>>>> static analysis tool.
>>>>
>>>> Signed-off-by: Daniil Tatianin <d-tatianin at yandex-team.ru>
>>>> ---
>>>>    drivers/scsi/cxgbi/libcxgbi.c | 3 +--
>>>>    1 file changed, 1 insertion(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/scsi/cxgbi/libcxgbi.c b/drivers/scsi/cxgbi/libcxgbi.c
>>>> index af281e271f88..2ff9810f42a9 100644
>>>> --- a/drivers/scsi/cxgbi/libcxgbi.c
>>>> +++ b/drivers/scsi/cxgbi/libcxgbi.c
>>>> @@ -1196,8 +1196,7 @@ void cxgbi_ddp_set_one_ppod(struct cxgbi_pagepod *ppod,
>>>>          if (offset == len) {
>>>>            offset = 0;
>>>> -        sg = sg_next(sg);
>>>> -        if (sg) {
>>>> +        if (sg && (sg = sg_next(sg))) {
>>>>                addr = sg_dma_address(sg);
>>>>                len = sg_dma_len(sg);
>>>>            }
>>>
>>> Is cxgbit_set_one_ppod the same function but it already has the extra
>>> sg check?
>>
>> Good catch! Certainly looks that way, albeit with messier indentation.
>>
>>> Should it be a libcxgb function in libcxgb_ppm.c?
>>
>> That makes sense to me. Should I just move both there?
> 
> I think you can move one function with a fix to libcxgb and kill the second one.
> Name the new function to cxgb_ddp_set_one_ppod then have cxgbi and cxgbt use it.

Yeah, thah's pretty much what I meant. Thank you!