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Re: [PATCH] qla2xxx: avoid maybe_uninitialized warning

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On Tue, 2016-03-15 at 22:40 +0100, Arnd Bergmann wrote:
> The qlt_check_reserve_free_req() function produces an incorrect 
> warning when CONFIG_PROFILE_ANNOTATED_BRANCHES is set:
> 
> drivers/scsi/qla2xxx/qla_target.c: In function
> 'qlt_check_reserve_free_req':
> drivers/scsi/qla2xxx/qla_target.c:1887:3: error: 'cnt_in' may be used
> uninitialized in this function [-Werror=maybe-uninitialized]
>    ql_dbg(ql_dbg_io, vha, 0x305a,
>    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>        "qla_target(%d): There is no room in the request ring: vha
> ->req->ring_index=%d, vha->req->cnt=%d, req_cnt=%d Req-out=%d Req
> -in=%d Req-Length=%d\n",
>       
>  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~
>        vha->vp_idx, vha->req->ring_index,
>        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>        vha->req->cnt, req_cnt, cnt, cnt_in, vha->req->length);
>        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/qla2xxx/qla_target.c:1887:3: error: 'cnt' may be used
> uninitialized in this function [-Werror=maybe-uninitialized]
> 
> The problem is that gcc fails to track the state of the condition 
> across an annotated branch.
> 
> This slightly rearranges the code to move the second if() block
> into the first one, to avoid the warning while retaining the
> behavior of the code.

I thought our usual policy was to ask someone to fix the compiler when
it emitted a spurious warning.

James

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[PATCH] qla2xxx: avoid maybe_uninitialized warning Arnd Bergmann <arnd@arndb.de> - 2016-03-15 22:50 +0100
  Re: [PATCH] qla2xxx: avoid maybe_uninitialized warning James Bottomley <jejb@linux.vnet.ibm.com> - 2016-03-15 22:50 +0100
    Re: [PATCH] qla2xxx: avoid maybe_uninitialized warning Arnd Bergmann <arnd@arndb.de> - 2016-03-16 14:10 +0100
      Re: [PATCH] qla2xxx: avoid maybe_uninitialized warning Himanshu Madhani <himanshu.madhani@qlogic.com> - 2016-03-16 15:10 +0100
        Re: [PATCH] qla2xxx: avoid maybe_uninitialized warning James Bottomley <jejb@linux.vnet.ibm.com> - 2016-03-16 15:30 +0100
  Re: [PATCH] qla2xxx: avoid maybe_uninitialized warning Tomas Henzl <thenzl@redhat.com> - 2016-03-16 16:10 +0100
    Re: [PATCH] qla2xxx: avoid maybe_uninitialized warning Tomas Henzl <thenzl@redhat.com> - 2016-03-16 16:20 +0100
    Re: [PATCH] qla2xxx: avoid maybe_uninitialized warning "Ewan D. Milne" <emilne@redhat.com> - 2016-03-16 16:50 +0100

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