From: Kanchan Joshi <[email protected]>
To: Chaitanya Kulkarni <[email protected]>
Cc: "[email protected]" <[email protected]>,
"[email protected]" <[email protected]>,
"[email protected]" <[email protected]>,
"[email protected]" <[email protected]>,
"[email protected]" <[email protected]>,
"[email protected]" <[email protected]>,
"[email protected]" <[email protected]>,
"[email protected]" <[email protected]>,
Anuj Gupta <[email protected]>
Subject: Re: [PATCH for-next v5 3/4] block: add helper to map bvec iterator for passthrough
Date: Thu, 8 Sep 2022 16:22:00 +0530 [thread overview]
Message-ID: <20220908105200.GB15034@test-zns> (raw)
In-Reply-To: <[email protected]>
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On Wed, Sep 07, 2022 at 03:32:26PM +0000, Chaitanya Kulkarni wrote:
>On 9/5/22 23:27, Kanchan Joshi wrote:
>> Add blk_rq_map_user_bvec which maps the bvec iterator into a bio and
>> places that into the request. This helper will be used in nvme for
>> uring-passthrough with fixed-buffer.
>> While at it, create another helper bio_map_get to reduce the code
>> duplication.
>>
>> Signed-off-by: Kanchan Joshi <[email protected]>
>> Signed-off-by: Anuj Gupta <[email protected]>
>> ---
>> block/blk-map.c | 94 +++++++++++++++++++++++++++++++++++++-----
>> include/linux/blk-mq.h | 1 +
>> 2 files changed, 85 insertions(+), 10 deletions(-)
>>
>> diff --git a/block/blk-map.c b/block/blk-map.c
>> index f3768876d618..e2f268167342 100644
>> --- a/block/blk-map.c
>> +++ b/block/blk-map.c
>> @@ -241,17 +241,10 @@ static void bio_map_put(struct bio *bio)
>> }
>> }
>>
>> -static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
>> +static struct bio *bio_map_get(struct request *rq, unsigned int nr_vecs,
>> gfp_t gfp_mask)
>> {
>> - unsigned int max_sectors = queue_max_hw_sectors(rq->q);
>> - unsigned int nr_vecs = iov_iter_npages(iter, BIO_MAX_VECS);
>> struct bio *bio;
>> - int ret;
>> - int j;
>> -
>> - if (!iov_iter_count(iter))
>> - return -EINVAL;
>>
>> if (rq->cmd_flags & REQ_POLLED) {
>> blk_opf_t opf = rq->cmd_flags | REQ_ALLOC_CACHE;
>> @@ -259,13 +252,31 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
>> bio = bio_alloc_bioset(NULL, nr_vecs, opf, gfp_mask,
>> &fs_bio_set);
>> if (!bio)
>> - return -ENOMEM;
>> + return NULL;
>> } else {
>> bio = bio_kmalloc(nr_vecs, gfp_mask);
>> if (!bio)
>> - return -ENOMEM;
>> + return NULL;
>> bio_init(bio, NULL, bio->bi_inline_vecs, nr_vecs, req_op(rq));
>> }
>> + return bio;
>> +}
>> +
>> +static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
>> + gfp_t gfp_mask)
>> +{
>> + unsigned int max_sectors = queue_max_hw_sectors(rq->q);
>> + unsigned int nr_vecs = iov_iter_npages(iter, BIO_MAX_VECS);
>> + struct bio *bio;
>> + int ret;
>> + int j;
>> +
>> + if (!iov_iter_count(iter))
>> + return -EINVAL;
>> +
>> + bio = bio_map_get(rq, nr_vecs, gfp_mask);
>> + if (bio == NULL)
>> + return -ENOMEM;
>>
>> while (iov_iter_count(iter)) {
>> struct page **pages, *stack_pages[UIO_FASTIOV];
>> @@ -612,6 +623,69 @@ 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;
>> +
>
>consider this (untested), it also sets the variable i data type same
>as it comparison variable in nr_segs the loop i.e. size_t :-
>
>+ struct bio_vec *bv, *bvec_arr, *bvprvp = NULL;
>+ struct request_queue *q = rq->q;
>+ struct queue_limits *lim = &q->limits;
>+ unsigned int nsegs = 0, bytes = 0;
>+ size_t iter_count, nr_segs, i;
>+ struct bio *bio;
>+ int ret;
>
>
>> + iter_count = iov_iter_count(iter);
>> + nr_segs = iter->nr_segs;
>> +
>> + if (!iter_count || (iter_count >> 9) > queue_max_hw_sectors(q))
>> + return -EINVAL;
>
>can we remove braces for iter_count >> 9 without impacting the intended
>functionality?
I think removing that make it hard to read.
I will fold all other changes you mentioned in v6.
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next prev parent reply other threads:[~2022-09-08 11:02 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20220906063719epcas5p3157e79583a5412a3be81f3d96f8aaadd@epcas5p3.samsung.com>
2022-09-06 6:27 ` [PATCH for-next v5 0/4] fixed-buffer for uring-cmd/passthru Kanchan Joshi
[not found] ` <CGME20220906063723epcas5p23946fd33031aee591210af1c3cd2d574@epcas5p2.samsung.com>
2022-09-06 6:27 ` [PATCH for-next v5 1/4] io_uring: introduce io_uring_cmd_import_fixed Kanchan Joshi
[not found] ` <CGME20220906063726epcas5p42f764b4c01b841dd1fc34abebcab02e6@epcas5p4.samsung.com>
2022-09-06 6:27 ` [PATCH for-next v5 2/4] io_uring: introduce fixed buffer support for io_uring_cmd Kanchan Joshi
[not found] ` <CGME20220906063729epcas5p1bf05e6873de0f7246234380d66c21fb9@epcas5p1.samsung.com>
2022-09-06 6:27 ` [PATCH for-next v5 3/4] block: add helper to map bvec iterator for passthrough Kanchan Joshi
2022-09-07 15:32 ` Chaitanya Kulkarni
2022-09-08 10:52 ` Kanchan Joshi [this message]
2022-09-08 14:46 ` Jens Axboe
2022-09-08 15:11 ` Pankaj Raghav
[not found] ` <CGME20220906063733epcas5p22984174bd6dbb2571152fea18af90924@epcas5p2.samsung.com>
2022-09-06 6:27 ` [PATCH for-next v5 4/4] nvme: wire up fixed buffer support for nvme passthrough Kanchan Joshi
2022-09-07 14:51 ` Chaitanya Kulkarni
2022-09-08 10:47 ` Kanchan Joshi
2022-09-08 14:50 ` Jens Axboe
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