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From: Anuj Gupta <[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 v12 10/12] block: extend functionality to map bvec iterator
Date: Fri, 30 Sep 2022 11:57:47 +0530	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

From: Kanchan Joshi <[email protected]>

Extend blk_rq_map_user_iov so that it can handle bvec iterator, using
the new blk_rq_map_user_bvec function. It maps the pages from bvec
iterator into a bio and place the bio into request.

This helper will be used by nvme for uring-passthrough path when IO is
done using pre-mapped buffers.

Signed-off-by: Kanchan Joshi <[email protected]>
Signed-off-by: Anuj Gupta <[email protected]>
Suggested-by: Christoph Hellwig <[email protected]>
---
 block/blk-map.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 71 insertions(+), 4 deletions(-)

diff --git a/block/blk-map.c b/block/blk-map.c
index d6ea377394a9..34735626b00f 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -548,6 +548,62 @@ int blk_rq_append_bio(struct request *rq, struct bio *bio)
 }
 EXPORT_SYMBOL(blk_rq_append_bio);
 
+/* Prepare bio for passthrough IO given ITER_BVEC iter */
+static int blk_rq_map_user_bvec(struct request *rq, const struct iov_iter *iter)
+{
+	struct request_queue *q = rq->q;
+	size_t nr_iter = iov_iter_count(iter);
+	size_t nr_segs = iter->nr_segs;
+	struct bio_vec *bvecs, *bvprvp = NULL;
+	struct queue_limits *lim = &q->limits;
+	unsigned int nsegs = 0, bytes = 0;
+	struct bio *bio;
+	size_t i;
+
+	if (!nr_iter || (nr_iter >> SECTOR_SHIFT) > queue_max_hw_sectors(q))
+		return -EINVAL;
+	if (nr_segs > queue_max_segments(q))
+		return -EINVAL;
+
+	/* no iovecs to alloc, as we already have a BVEC iterator */
+	bio = blk_rq_map_bio_alloc(rq, 0, GFP_KERNEL);
+	if (bio == NULL)
+		return -ENOMEM;
+
+	bio_iov_bvec_set(bio, (struct iov_iter *)iter);
+	blk_rq_bio_prep(rq, bio, nr_segs);
+
+	/* loop to perform a bunch of sanity checks */
+	bvecs = (struct bio_vec *)iter->bvec;
+	for (i = 0; i < nr_segs; i++) {
+		struct bio_vec *bv = &bvecs[i];
+
+		/*
+		 * If the queue doesn't support SG gaps and adding this
+		 * offset would create a gap, fallback to copy.
+		 */
+		if (bvprvp && bvec_gap_to_prev(lim, bvprvp, bv->bv_offset)) {
+			blk_mq_map_bio_put(bio);
+			return -EREMOTEIO;
+		}
+		/* check full condition */
+		if (nsegs >= nr_segs || bytes > UINT_MAX - bv->bv_len)
+			goto put_bio;
+		if (bytes + bv->bv_len > nr_iter)
+			goto put_bio;
+		if (bv->bv_offset + bv->bv_len > PAGE_SIZE)
+			goto put_bio;
+
+		nsegs++;
+		bytes += bv->bv_len;
+		bvprvp = bv;
+	}
+	return 0;
+put_bio:
+	blk_mq_map_bio_put(bio);
+	return -EINVAL;
+}
+
 /**
  * blk_rq_map_user_iov - map user data to a request, for passthrough requests
  * @q:		request queue where request should be inserted
@@ -567,24 +623,35 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
 			struct rq_map_data *map_data,
 			const struct iov_iter *iter, gfp_t gfp_mask)
 {
-	bool copy = false;
+	bool copy = false, map_bvec = false;
 	unsigned long align = q->dma_pad_mask | queue_dma_alignment(q);
 	struct bio *bio = NULL;
 	struct iov_iter i;
 	int ret = -EINVAL;
 
-	if (!iter_is_iovec(iter))
-		goto fail;
-
 	if (map_data)
 		copy = true;
 	else if (blk_queue_may_bounce(q))
 		copy = true;
 	else if (iov_iter_alignment(iter) & align)
 		copy = true;
+	else if (iov_iter_is_bvec(iter))
+		map_bvec = true;
+	else if (!iter_is_iovec(iter))
+		copy = true;
 	else if (queue_virt_boundary(q))
 		copy = queue_virt_boundary(q) & iov_iter_gap_alignment(iter);
 
+	if (map_bvec) {
+		ret = blk_rq_map_user_bvec(rq, iter);
+		if (!ret)
+			return 0;
+		if (ret != -EREMOTEIO)
+			goto fail;
+		/* fall back to copying the data on limits mismatches */
+		copy = true;
+	}
+
 	i = *iter;
 	do {
 		if (copy)
-- 
2.25.1


  parent reply	other threads:[~2022-09-30  6:45 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20220930063754epcas5p2aff33c952032713a39604388eacda910@epcas5p2.samsung.com>
2022-09-30  6:27 ` [PATCH for-next v12 00/12] Fixed-buffer for uring-cmd/passthru Anuj Gupta
     [not found]   ` <CGME20220930063805epcas5p2c8eb80f32507f011baedc6d6b4d3f38d@epcas5p2.samsung.com>
2022-09-30  6:27     ` [PATCH for-next v12 01/12] io_uring: add io_uring_cmd_import_fixed Anuj Gupta
     [not found]   ` <CGME20220930063809epcas5p328b9e14ead49e9612b905e6f5b6682f7@epcas5p3.samsung.com>
2022-09-30  6:27     ` [PATCH for-next v12 02/12] io_uring: introduce fixed buffer support for io_uring_cmd Anuj Gupta
2022-09-30 13:42       ` Jens Axboe
2022-09-30 14:04         ` Anuj gupta
     [not found]   ` <CGME20220930063811epcas5p43cce58f5e1589c3e3780ce0cfd563986@epcas5p4.samsung.com>
2022-09-30  6:27     ` [PATCH for-next v12 03/12] block: add blk_rq_map_user_io Anuj Gupta
     [not found]   ` <CGME20220930063815epcas5p1e056d6a2a53949296a7657de804fd2ec@epcas5p1.samsung.com>
2022-09-30  6:27     ` [PATCH for-next v12 04/12] scsi: Use blk_rq_map_user_io helper Anuj Gupta
     [not found]   ` <CGME20220930063818epcas5p4e321f0efa5a53759ea19eb8f1c63deef@epcas5p4.samsung.com>
2022-09-30  6:27     ` [PATCH for-next v12 05/12] nvme: " Anuj Gupta
     [not found]   ` <CGME20220930063821epcas5p48d4ec5136d487ea779ac74e2c0b740ac@epcas5p4.samsung.com>
2022-09-30  6:27     ` [PATCH for-next v12 06/12] nvme: refactor nvme_add_user_metadata Anuj Gupta
     [not found]   ` <CGME20220930063824epcas5p4f829f3b8673e2603cdc9a799ca44ea6e@epcas5p4.samsung.com>
2022-09-30  6:27     ` [PATCH for-next v12 07/12] nvme: refactor nvme_alloc_request Anuj Gupta
     [not found]   ` <CGME20220930063826epcas5p491d9bc62214c1d7c8c24c883299edfb7@epcas5p4.samsung.com>
2022-09-30  6:27     ` [PATCH for-next v12 08/12] block: rename bio_map_put to blk_mq_map_bio_put Anuj Gupta
     [not found]   ` <CGME20220930063828epcas5p2bfddb254b0dffde77e99c2acc4440bde@epcas5p2.samsung.com>
2022-09-30  6:27     ` [PATCH for-next v12 09/12] block: factor out blk_rq_map_bio_alloc helper Anuj Gupta
     [not found]   ` <CGME20220930063831epcas5p4b6a8559dedd39ef423a0b9a317163969@epcas5p4.samsung.com>
2022-09-30  6:27     ` Anuj Gupta [this message]
     [not found]   ` <CGME20220930063833epcas5p40fbff95f9d132f5a42dda80d307426e9@epcas5p4.samsung.com>
2022-09-30  6:27     ` [PATCH for-next v12 11/12] nvme: pass ubuffer as an integer Anuj Gupta
     [not found]   ` <CGME20220930063835epcas5p2812f8e3d0758b19c01198034fcddc019@epcas5p2.samsung.com>
2022-09-30  6:27     ` [PATCH for-next v12 12/12] nvme: wire up fixed buffer support for nvme passthrough Anuj Gupta
2022-09-30 14:04   ` [PATCH for-next v12 00/12] Fixed-buffer for uring-cmd/passthru Jens Axboe

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