| Message ID | 20200513110419.2362556-4-hch@lst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/4] block: move the call to blk_queue_enter_live out of blk_mq_get_request | expand |
On 13/05/2020 13:04, Christoph Hellwig wrote: > rq = blk_mq_get_request(q, NULL, &alloc_data); > - blk_queue_exit(q); > - > - if (!rq) { > - blk_queue_exit(q); > - return ERR_PTR(-EWOULDBLOCK); > - } > + if (!rq) > + goto out_queue_exit; > > return rq; > +out_queue_exit: > + blk_queue_exit(q); > + return ERR_PTR(ret); I know success handling is discouraged in the kernel, but I think rq = blk_mq_get_request(q, NULL, &alloc_data); if (rq) return rq; out_queue_exit: blk_queue_exit(q); return ERR_PTR(ret); looks nicer, doesn't it?
On Wed, May 13, 2020 at 12:02:10PM +0000, Johannes Thumshirn wrote: > I know success handling is discouraged in the kernel, but I think > > rq = blk_mq_get_request(q, NULL, &alloc_data); > if (rq) > return rq; > > out_queue_exit: > blk_queue_exit(q); > return ERR_PTR(ret); > > looks nicer, doesn't it? Not at all. A flow of most common case stays in line, everything else jumps out really helps with reading.
diff --git a/block/blk-mq.c b/block/blk-mq.c index a3491c1397501..81b7af7be70b5 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -445,24 +445,22 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q, * Check if the hardware context is actually mapped to anything. * If not tell the caller that it should skip this queue. */ + ret = -EXDEV; alloc_data.hctx = q->queue_hw_ctx[hctx_idx]; - if (!blk_mq_hw_queue_mapped(alloc_data.hctx)) { - blk_queue_exit(q); - return ERR_PTR(-EXDEV); - } + if (!blk_mq_hw_queue_mapped(alloc_data.hctx)) + goto out_queue_exit; cpu = cpumask_first_and(alloc_data.hctx->cpumask, cpu_online_mask); alloc_data.ctx = __blk_mq_get_ctx(q, cpu); - blk_queue_enter_live(q); + ret = -EWOULDBLOCK; rq = blk_mq_get_request(q, NULL, &alloc_data); - blk_queue_exit(q); - - if (!rq) { - blk_queue_exit(q); - return ERR_PTR(-EWOULDBLOCK); - } + if (!rq) + goto out_queue_exit; return rq; +out_queue_exit: + blk_queue_exit(q); + return ERR_PTR(ret); } EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
No need for two queue references. Signed-off-by: Christoph Hellwig <hch@lst.de> --- block/blk-mq.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-)