Hi Jens,

After merging the block tree, today's linux-next build (arm
multi_v7_defconfig) produced these warnings:

block/blk-merge.c: In function 'blk_rq_map_sg':
block/blk-merge.c:133:8: warning: 'bvprv.bv_len' may be used uninitialized in this function [-Wuninitialized]
block/blk-merge.c:171:23: note: 'bvprv.bv_len' was declared here
block/blk-merge.c:133:8: warning: 'bvprv.bv_page' may be used uninitialized in this function [-Wuninitialized]
block/blk-merge.c:171:23: note: 'bvprv.bv_page' was declared here
block/blk-merge.c:133:8: warning: 'bvprv.bv_offset' may be used uninitialized in this function [-Wuninitialized]
block/blk-merge.c:171:23: note: 'bvprv.bv_offset' was declared here
block/blk-merge.c: In function 'blk_bio_map_sg':
block/blk-merge.c:133:8: warning: 'bvprv.bv_len' may be used uninitialized in this function [-Wuninitialized]
block/blk-merge.c:233:23: note: 'bvprv.bv_len' was declared here
block/blk-merge.c:133:8: warning: 'bvprv.bv_offset' may be used uninitialized in this function [-Wuninitialized]
block/blk-merge.c:233:23: note: 'bvprv.bv_offset' was declared here
block/blk-merge.c:133:8: warning: 'bvprv.bv_page' may be used uninitialized in this function [-Wuninitialized]
block/blk-merge.c:233:23: note: 'bvprv.bv_page' was declared here
block/blk-merge.c: In function 'attempt_merge':
block/blk-merge.c:108:7: warning: 'end_bv.bv_offset' may be used uninitialized in this function [-Wuninitialized]
block/blk-merge.c:89:17: note: 'end_bv.bv_offset' was declared here
block/blk-merge.c:108:7: warning: 'end_bv.bv_page' may be used uninitialized in this function [-Wuninitialized]
block/blk-merge.c:89:17: note: 'end_bv.bv_page' was declared here
block/blk-merge.c:108:7: warning: 'end_bv.bv_len' may be used uninitialized in this function [-Wuninitialized]
block/blk-merge.c:89:17: note: 'end_bv.bv_len' was declared here

arm has its own definition of BIOVEC_PHYS_MERGEABLE() if that is relevant.
-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au