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blk-mq: for_each_* macro correctness

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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>
This commit is contained in:
Jose Alonso 2014-01-28 08:09:46 -07:00 committed by Jens Axboe
parent 17a05cca99
commit 0d0b7d4279
1 changed files with 6 additions and 6 deletions
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12
include/linux/blk-mq.h
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@ -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) \
({ \