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From: Kanchan Joshi <[email protected]>
To: [email protected], [email protected], [email protected]
Cc: [email protected], [email protected],
	[email protected], [email protected],
	[email protected], Kanchan Joshi <[email protected]>,
	Anuj Gupta <[email protected]>
Subject: [PATCH for-next 3/4] block: add helper to map bvec iterator for passthrough
Date: Fri, 19 Aug 2022 16:00:20 +0530	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

Add blk_rq_map_user_fixedb which maps the bvec iterator into a bio and
places that into the request.
This helper is to be used in nvme for uring-passthrough with
fixed-buffer.

Signed-off-by: Kanchan Joshi <[email protected]>
Signed-off-by: Anuj Gupta <[email protected]>
---
 block/blk-map.c        | 71 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/blk-mq.h |  1 +
 2 files changed, 72 insertions(+)

diff --git a/block/blk-map.c b/block/blk-map.c
index d0ff80a9902e..ee17cc78bf00 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -611,6 +611,77 @@ int blk_rq_map_user(struct request_queue *q, struct request *rq,
 }
 EXPORT_SYMBOL(blk_rq_map_user);
 
+/* Prepare bio for passthrough IO given an existing bvec iter */
+int blk_rq_map_user_bvec(struct request *rq, struct iov_iter *iter)
+{
+	struct request_queue *q = rq->q;
+	size_t iter_count, nr_segs;
+	struct bio *bio;
+	struct bio_vec *bv, *bvec_arr, *bvprvp = NULL;
+	struct queue_limits *lim = &q->limits;
+	unsigned int nsegs = 0, bytes = 0;
+	int ret, i;
+
+	iter_count = iov_iter_count(iter);
+	nr_segs = iter->nr_segs;
+
+	if (!iter_count || (iter_count >> 9) > queue_max_hw_sectors(q))
+		return -EINVAL;
+	if (nr_segs > queue_max_segments(q))
+		return -EINVAL;
+	if (rq->cmd_flags & REQ_POLLED) {
+		blk_opf_t opf = rq->cmd_flags | REQ_ALLOC_CACHE;
+
+		/* no iovecs to alloc, as we already have a BVEC iterator */
+		bio = bio_alloc_bioset(NULL, 0, opf, GFP_KERNEL,
+					&fs_bio_set);
+		if (!bio)
+			return -ENOMEM;
+	} else {
+		bio = bio_kmalloc(0, GFP_KERNEL);
+		if (!bio)
+			return -ENOMEM;
+		bio_init(bio, NULL, bio->bi_inline_vecs, 0, req_op(rq));
+	}
+	bio_iov_bvec_set(bio, iter);
+	blk_rq_bio_prep(rq, bio, nr_segs);
+
+	/* loop to perform a bunch of sanity checks */
+	bvec_arr = (struct bio_vec *)iter->bvec;
+	for (i = 0; i < nr_segs; i++) {
+		bv = &bvec_arr[i];
+		/*
+		 * If the queue doesn't support SG gaps and adding this
+		 * offset would create a gap, disallow it.
+		 */
+		if (bvprvp && bvec_gap_to_prev(lim, bvprvp, bv->bv_offset)) {
+			ret = -EINVAL;
+			goto out_free;
+		}
+
+		/* check full condition */
+		if (nsegs >= nr_segs || bytes > UINT_MAX - bv->bv_len) {
+			ret = -EINVAL;
+			goto out_free;
+		}
+
+		if (bytes + bv->bv_len <= iter_count &&
+				bv->bv_offset + bv->bv_len <= PAGE_SIZE) {
+			nsegs++;
+			bytes += bv->bv_len;
+		} else {
+			ret = -EINVAL;
+			goto out_free;
+		}
+		bvprvp = bv;
+	}
+	return 0;
+out_free:
+	bio_map_put(bio);
+	return ret;
+}
+EXPORT_SYMBOL(blk_rq_map_user_bvec);
+
 /**
  * blk_rq_unmap_user - unmap a request with user data
  * @bio:	       start of bio list
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 9d1af7a0a401..a7c9c836d2f3 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -971,6 +971,7 @@ struct rq_map_data {
 	bool from_user;
 };
 
+int blk_rq_map_user_fixedb(struct request *rq, struct iov_iter *iter);
 int blk_rq_map_user(struct request_queue *, struct request *,
 		struct rq_map_data *, void __user *, unsigned long, gfp_t);
 int blk_rq_map_user_iov(struct request_queue *, struct request *,
-- 
2.25.1


  parent reply	other threads:[~2022-08-19 10:40 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20220819104031epcas5p3d485526e1b2b42078ccce7e40a74b7f5@epcas5p3.samsung.com>
2022-08-19 10:30 ` [PATCH for-next 0/4] fixed-buffer for uring-cmd/passthrough Kanchan Joshi
     [not found]   ` <CGME20220819104036epcas5p2bb4d9b2cccbdfcdb460e085abe7fd1a8@epcas5p2.samsung.com>
2022-08-19 10:30     ` [PATCH for-next 1/4] io_uring: introduce io_uring_cmd_import_fixed Kanchan Joshi
     [not found]   ` <CGME20220819104038epcas5p265c9385cfd9189d20ebfffeaa4d5efae@epcas5p2.samsung.com>
2022-08-19 10:30     ` [PATCH for-next 2/4] io_uring: introduce fixed buffer support for io_uring_cmd Kanchan Joshi
2022-08-22 10:58       ` Pavel Begunkov
2022-08-22 11:33         ` Kanchan Joshi
2022-08-25  9:34           ` Pavel Begunkov
2022-08-25 16:02             ` Kanchan Joshi
     [not found]   ` <CGME20220819104042epcas5p177f384cd4c15918f666c7eacc4dfab4c@epcas5p1.samsung.com>
2022-08-19 10:30     ` Kanchan Joshi [this message]
     [not found]   ` <CGME20220819104045epcas5p117a9fcb0c3143e877e75e24ceba4f381@epcas5p1.samsung.com>
2022-08-19 10:30     ` [PATCH for-next 4/4] nvme: wire up fixed buffer support for nvme passthrough Kanchan Joshi

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