From: Logan Gunthorpe <logang@deltatee.com>
To: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org,
linux-rdma@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
Bjorn Helgaas <bhelgaas@google.com>,
Dan Williams <dan.j.williams@intel.com>,
Sagi Grimberg <sagi@grimberg.me>, Keith Busch <kbusch@kernel.org>,
Jason Gunthorpe <jgg@ziepe.ca>,
Stephen Bates <sbates@raithlin.com>,
Logan Gunthorpe <logang@deltatee.com>
Subject: [RFC PATCH 16/28] block: Implement mapping dma-direct requests to SGs in blk_rq_map_sg()
Date: Thu, 20 Jun 2019 10:12:28 -0600 [thread overview]
Message-ID: <20190620161240.22738-17-logang@deltatee.com> (raw)
In-Reply-To: <20190620161240.22738-1-logang@deltatee.com>
blk_rq_map_sg() just needs to move the dma_vec into the dma_address
of the sgl. Callers will need to ensure not to call dma_map_sg()
for dma-direct requests.
This will likely get less ugly with Christoph's proposed cleanup
to the DMA API. It will be much simpler if devices are just
calling a dma_map_bio() and don't have to worry about dma-direct
requests.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
block/blk-merge.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index a7a5453987f9..ccd6c44b9f6e 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -545,6 +545,69 @@ static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio,
return nsegs;
}
+static unsigned blk_dvec_map_sg(struct request_queue *q,
+ struct dma_vec *dvec, struct scatterlist *sglist,
+ struct scatterlist **sg)
+{
+ unsigned nbytes = dvec->dv_len;
+ unsigned nsegs = 0, total = 0;
+
+ while (nbytes > 0) {
+ unsigned seg_size;
+
+ *sg = blk_next_sg(sg, sglist);
+
+ seg_size = get_max_segment_size(q, total);
+ seg_size = min(nbytes, seg_size);
+
+ (*sg)->dma_address = dvec->dv_addr + total;
+ sg_dma_len(*sg) = seg_size;
+
+ total += seg_size;
+ nbytes -= seg_size;
+ nsegs++;
+ }
+
+ return nsegs;
+}
+
+static inline void
+__blk_segment_dma_map_sg(struct request_queue *q, struct dma_vec *dvec,
+ struct scatterlist *sglist, struct dma_vec *dvprv,
+ struct scatterlist **sg, int *nsegs)
+{
+ int nbytes = dvec->dv_len;
+
+ if (*sg) {
+ if ((*sg)->length + nbytes > queue_max_segment_size(q))
+ goto new_segment;
+ if (!dmavec_phys_mergeable(q, dvprv, dvec))
+ goto new_segment;
+
+ (*sg)->length += nbytes;
+ } else {
+new_segment:
+ (*nsegs) += blk_dvec_map_sg(q, dvec, sglist, sg);
+ }
+ *dvprv = *dvec;
+}
+
+static int __blk_dma_bios_map_sg(struct request_queue *q, struct bio *bio,
+ struct scatterlist *sglist,
+ struct scatterlist **sg)
+{
+ struct dma_vec dvec, dvprv = {};
+ struct bvec_iter iter;
+ int nsegs = 0;
+
+ for_each_bio(bio)
+ bio_for_each_dvec(dvec, bio, iter)
+ __blk_segment_dma_map_sg(q, &dvec, sglist, &dvprv,
+ sg, &nsegs);
+
+ return nsegs;
+}
+
/*
* map a request to scatterlist, return number of sg entries setup. Caller
* must make sure sg can hold rq->nr_phys_segments entries
@@ -559,6 +622,8 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
nsegs = __blk_bvec_map_sg(rq->special_vec, sglist, &sg);
else if (rq->bio && bio_op(rq->bio) == REQ_OP_WRITE_SAME)
nsegs = __blk_bvec_map_sg(bio_iovec(rq->bio), sglist, &sg);
+ else if (blk_rq_is_dma_direct(rq))
+ nsegs = __blk_dma_bios_map_sg(q, rq->bio, sglist, &sg);
else if (rq->bio)
nsegs = __blk_bios_map_sg(q, rq->bio, sglist, &sg);
--
2.20.1
next prev parent reply other threads:[~2019-06-20 16:14 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-20 16:12 [RFC PATCH 00/28] Removing struct page from P2PDMA Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 01/28] block: Introduce DMA direct request type Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 02/28] block: Add dma_vec structure Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 03/28] block: Warn on mis-use of dma-direct bios Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 04/28] block: Never bounce " Logan Gunthorpe
2019-06-20 17:23 ` Jason Gunthorpe
2019-06-20 18:38 ` Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 05/28] block: Skip dma-direct bios in bio_integrity_prep() Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 06/28] block: Support dma-direct bios in bio_advance_iter() Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 07/28] block: Use dma_vec length in bio_cur_bytes() for dma-direct bios Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 08/28] block: Introduce dmavec_phys_mergeable() Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 09/28] block: Introduce vec_gap_to_prev() Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 10/28] block: Create generic vec_split_segs() from bvec_split_segs() Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 11/28] block: Create blk_segment_split_ctx Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 12/28] block: Create helper for bvec_should_split() Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 13/28] block: Generalize bvec_should_split() Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 14/28] block: Support splitting dma-direct bios Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 15/28] block: Support counting dma-direct bio segments Logan Gunthorpe
2019-06-20 16:12 ` Logan Gunthorpe [this message]
2019-06-20 16:12 ` [RFC PATCH 17/28] block: Introduce queue flag to indicate support for dma-direct bios Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 18/28] block: Introduce bio_add_dma_addr() Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 19/28] nvme-pci: Support dma-direct bios Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 20/28] IB/core: Introduce API for initializing a RW ctx from a DMA address Logan Gunthorpe
2019-06-20 16:49 ` Jason Gunthorpe
2019-06-20 16:59 ` Logan Gunthorpe
2019-06-20 17:11 ` Jason Gunthorpe
2019-06-20 18:24 ` Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 21/28] nvmet: Split nvmet_bdev_execute_rw() into a helper function Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 22/28] nvmet: Use DMA addresses instead of struct pages for P2P Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 23/28] nvme-pci: Remove support for PCI_P2PDMA requests Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 24/28] block: Remove PCI_P2PDMA queue flag Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 25/28] IB/core: Remove P2PDMA mapping support in rdma_rw_ctx Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 26/28] PCI/P2PDMA: Remove SGL helpers Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 27/28] PCI/P2PDMA: Remove struct pages that back P2PDMA memory Logan Gunthorpe
2019-06-20 16:12 ` [RFC PATCH 28/28] memremap: Remove PCI P2PDMA page memory type Logan Gunthorpe
2019-06-20 18:45 ` [RFC PATCH 00/28] Removing struct page from P2PDMA Dan Williams
2019-06-20 19:33 ` Jason Gunthorpe
2019-06-20 20:18 ` Dan Williams
2019-06-20 20:51 ` Logan Gunthorpe
2019-06-21 17:47 ` Jason Gunthorpe
2019-06-21 17:54 ` Dan Williams
2019-06-24 7:31 ` Christoph Hellwig
2019-06-24 13:46 ` Jason Gunthorpe
2019-06-24 13:50 ` Christoph Hellwig
2019-06-24 13:55 ` Jason Gunthorpe
2019-06-24 16:53 ` Logan Gunthorpe
2019-06-24 18:16 ` Jason Gunthorpe
2019-06-24 18:28 ` Logan Gunthorpe
2019-06-24 18:54 ` Jason Gunthorpe
2019-06-24 19:37 ` Logan Gunthorpe
2019-06-24 16:10 ` Logan Gunthorpe
2019-06-25 7:18 ` Christoph Hellwig
2019-06-20 19:34 ` Logan Gunthorpe
2019-06-20 23:40 ` Dan Williams
2019-06-20 23:42 ` Logan Gunthorpe
2019-06-24 7:27 ` Christoph Hellwig
2019-06-24 16:07 ` Logan Gunthorpe
2019-06-25 7:20 ` Christoph Hellwig
2019-06-25 15:57 ` Logan Gunthorpe
2019-06-25 17:01 ` Christoph Hellwig
2019-06-25 19:54 ` Logan Gunthorpe
2019-06-26 6:57 ` Christoph Hellwig
2019-06-26 18:31 ` Logan Gunthorpe
2019-06-26 20:21 ` Jason Gunthorpe
2019-06-26 20:39 ` Dan Williams
2019-06-26 20:54 ` Jason Gunthorpe
2019-06-26 20:55 ` Logan Gunthorpe
2019-06-26 20:45 ` Logan Gunthorpe
2019-06-26 21:00 ` Jason Gunthorpe
2019-06-26 21:18 ` Logan Gunthorpe
2019-06-27 6:32 ` Jason Gunthorpe
2019-06-27 16:09 ` Logan Gunthorpe
2019-06-27 16:35 ` Jason Gunthorpe
2019-06-27 16:49 ` Logan Gunthorpe
2019-06-28 4:57 ` Jason Gunthorpe
2019-06-28 16:22 ` Logan Gunthorpe
2019-06-28 17:29 ` Jason Gunthorpe
2019-06-28 18:29 ` Logan Gunthorpe
2019-06-28 19:09 ` Jason Gunthorpe
2019-06-28 19:35 ` Logan Gunthorpe
2019-07-02 22:45 ` Jason Gunthorpe
2019-07-02 22:52 ` Logan Gunthorpe
2019-06-27 9:08 ` Christoph Hellwig
2019-06-27 16:30 ` Logan Gunthorpe
2019-06-27 17:00 ` Christoph Hellwig
2019-06-27 18:00 ` Logan Gunthorpe
2019-06-28 13:38 ` Christoph Hellwig
2019-06-28 15:54 ` Logan Gunthorpe
2019-06-27 9:01 ` Christoph Hellwig
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