On Mon, Apr 01, 2019 at 08:25:00AM -0600, Jens Axboe wrote:
> Hi Ming,
>
> I'm getting this one when building the new set with gcc 8.3.0:
>
>
> -- In file included from block/blk-merge.c:13:
> block/blk-merge.c: In function ‘blk_rq_map_sg’:
> block/blk.h:73:56: warning: ‘bvec.bv_offset’ may be used uninitialized in this function [-Wmaybe-uninitialized]
> phys_addr_t addr1 = page_to_phys(vec1->bv_page) + vec1->bv_offset;
> ~~~~^~~~~~~~~~~
> block/blk-merge.c:530:17: note: ‘bvec.bv_offset’ was declared here
> struct bio_vec bvec, bvprv = { NULL };
> ^~~~
> In file included from block/blk-merge.c:13:
> block/blk.h:76:18: warning: ‘bvec.bv_len’ may be used uninitialized in this function [-Wmaybe-uninitialized]
> if (addr1 + vec1->bv_len != addr2)
> ~~~~^~~~~~~~
> block/blk-merge.c:530:17: note: ‘bvec.bv_len’ was declared here
> struct bio_vec bvec, bvprv = { NULL };
> ^~~~
> In file included from ./arch/x86/include/asm/page.h:76,
> from ./arch/x86/include/asm/thread_info.h:12,
> from ./include/linux/thread_info.h:38,
> from ./arch/x86/include/asm/preempt.h:7,
> from ./include/linux/preempt.h:78,
> from ./include/linux/spinlock.h:51,
> from ./include/linux/seqlock.h:36,
> from ./include/linux/time.h:6,
> from ./include/linux/stat.h:19,
> from ./include/linux/module.h:10,
> from block/blk-merge.c:6:
> ./include/asm-generic/memory_model.h:55:52: warning: ‘bvec.bv_page’ may be used uninitialized in this function [-Wmaybe-uninitialized]
> #define __page_to_pfn(page) (unsigned long)((page) - vmemmap)
> ^
> block/blk-merge.c:530:17: note: ‘bvec.bv_page’ was declared here
> struct bio_vec bvec, bvprv = { NULL };
> ^~~~
It is one issue only if one bio doesn't include any bvec, I will post a
patch soon to fix it.
Thanks,
Ming
