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authorJose Alonso <joalonsof@gmail.com>2014-01-28 19:09:46 +0400
committerJens Axboe <axboe@kernel.dk>2014-01-28 19:09:46 +0400
commit0d0b7d427987f6e98b6f32e84ee071f36f85c3d4 (patch)
tree49e20246644048c004f1b1d3c95440538465a12b /include/linux
parent17a05cca99d952f5b4766fa48a2703548966636a (diff)
downloadlinux-0d0b7d427987f6e98b6f32e84ee071f36f85c3d4.tar.xz
blk-mq: for_each_* macro correctness
I observed that there are for_each macros that do an extra memory access beyond the defined area. Normally this does not cause problems. But, this can cause exceptions. For example: if the area is allocated at the end of a page and the next page is not accessible. For correctness, I suggest changing the arguments of the 'for loop' like others 'for_each' do in the kernel. Signed-off-by: Jose Alonso <joalonsof@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/blk-mq.h12
1 files changed, 6 insertions, 6 deletions
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 851d34b7ac26..161b23105b1e 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -158,16 +158,16 @@ static inline struct request *blk_mq_tag_to_rq(struct blk_mq_hw_ctx *hctx,
}
#define queue_for_each_hw_ctx(q, hctx, i) \
- for ((i) = 0, hctx = (q)->queue_hw_ctx[0]; \
- (i) < (q)->nr_hw_queues; (i)++, hctx = (q)->queue_hw_ctx[i])
+ for ((i) = 0; (i) < (q)->nr_hw_queues && \
+ ({ hctx = (q)->queue_hw_ctx[i]; 1; }); (i)++)
#define queue_for_each_ctx(q, ctx, i) \
- for ((i) = 0, ctx = per_cpu_ptr((q)->queue_ctx, 0); \
- (i) < (q)->nr_queues; (i)++, ctx = per_cpu_ptr(q->queue_ctx, (i)))
+ for ((i) = 0; (i) < (q)->nr_queues && \
+ ({ ctx = per_cpu_ptr((q)->queue_ctx, (i)); 1; }); (i)++)
#define hctx_for_each_ctx(hctx, ctx, i) \
- for ((i) = 0, ctx = (hctx)->ctxs[0]; \
- (i) < (hctx)->nr_ctx; (i)++, ctx = (hctx)->ctxs[(i)])
+ for ((i) = 0; (i) < (hctx)->nr_ctx && \
+ ({ ctx = (hctx)->ctxs[(i)]; 1; }); (i)++)
#define blk_ctx_sum(q, sum) \
({ \