Re: [GIT PULL] SG changes for 4.3

[Jens Axboe <axboe@fb.com>]

On 09/02/2015 04:41 PM, Jens Axboe wrote:
> On 09/02/2015 04:34 PM, Linus Torvalds wrote:
>> Jens,
>>
>> On Wed, Sep 2, 2015 at 9:58 AM, Jens Axboe <axboe@fb.com> wrote:
>>>
>>> This pull request contains a set of scatter-gather related changes/fixes
>>> for 4.3. It contains:
>>
>> This results in several new and annoying warnings. They may all be ok
>> code, but they are very distracting. Please stop introducing new
>> warnings to the build, because by now most of the warnings I see come
>> from the block layer.
>>
>>     block/blk-merge.c: In function ‘blk_queue_split’:
>>     include/linux/blkdev.h:1368:21: warning: ‘bvprv.bv_offset’ may be
>> used uninitialized in this function [-Wmaybe-uninitialized]
>>       ((bprv->bv_offset + bprv->bv_len) & queue_virt_boundary(q));
>>
>> (it gives this for bv_len too). The reason seems to be that disgusting
>> situation where "bvprv" is uninitiatlized unless "split" is true, and
>> the code looks like it is correct, but the compiler clearly has a hard
>> time seeing it. It took me a while too, so I can't really blame it.
>>
>> Either initialize bvprv to something explicit, or make the code clear
>> enough that the compiler can see that it is never used uninitialized.
>> Because those compiler warnings are sometimes real, and we can't just
>> ignore them.
>>
>> There was another type-based warning introduced by your core block
>> pull (size_t vs unsigned int).
>
> I think it's a repeat offender that got reintroduced. I'll fix it up.

This seems to make it happier. Will go out later in the merge window.

http://git.kernel.dk/cgit/linux-block/commit/?h=for-linus&id=5014c311baa2b21384321fa4a9f617a92e3e56f0

-- 
Jens Axboe