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From: Ming Lei <tom.leiming@gmail.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	Ming Lei <ming.lei@redhat.com>,
	linux-block <linux-block@vger.kernel.org>
Subject: Re: [PATCH 1/5] block: rewrite blk_bvec_map_sg to avoid a nth_page call
Date: Fri, 19 Apr 2019 10:27:44 +0800	[thread overview]
Message-ID: <CACVXFVPvz0H_vN1tafNGyk2E+gkoM0q6ab8Gt=J0fuhW3MGj8A@mail.gmail.com> (raw)
In-Reply-To: <20190417215904.GA23015@roeck-us.net>

On Thu, Apr 18, 2019 at 5:59 AM Guenter Roeck <linux@roeck-us.net> wrote:
>
> On Wed, Apr 17, 2019 at 07:27:24AM +0200, Christoph Hellwig wrote:
> > Now that I've fixed the sparc32 iommu code in another thread:  can
> > you send me your rootfs and qemu arm command line for the failing
> > one?  I have a hard time parsing your buildbot output.
>
> FWIW: mmc_blk_data_prep() calls blk_rq_map_sg() with a large offset value.
> The old code translated this into:
>
> blk_bvec_map_sg(q=c77a0000 len=13824 offset=18944)
>   sg_set_page(sg=c6015000 p=c7efd180 l=13824 o=2560)
>
> The new code leaves offset unchanged:
>
> blk_bvec_map_sg(q=c76c0528 len=13824 offset=18944)
>   sg_set_page(sg=c6035000 p=c7f2af00 l=13824 o=18944)
>
> Traceback:
>
> [<c065e3d4>] (blk_rq_map_sg) from [<c0ca1444>] (mmc_blk_data_prep+0x1b0/0x2c8)
> [<c0ca1444>] (mmc_blk_data_prep) from [<c0ca15ac>] (mmc_blk_rw_rq_prep+0x50/0x178)
> [<c0ca15ac>] (mmc_blk_rw_rq_prep) from [<c0ca48bc>] (mmc_blk_mq_issue_rq+0x290/0x878)
> [<c0ca48bc>] (mmc_blk_mq_issue_rq) from [<c0ca52e4>] (mmc_mq_queue_rq+0x128/0x234)
> [<c0ca52e4>] (mmc_mq_queue_rq) from [<c066350c>] (blk_mq_dispatch_rq_list+0xc8/0x5e8)
> [<c066350c>] (blk_mq_dispatch_rq_list) from [<c06681a8>] (blk_mq_do_dispatch_sched+0x60/0xfc)
> [<c06681a8>] (blk_mq_do_dispatch_sched) from [<c06688b8>] (blk_mq_sched_dispatch_requests+0x134/0x1b0)
> [<c06688b8>] (blk_mq_sched_dispatch_requests) from [<c0661f08>] (__blk_mq_run_hw_queue+0xa4/0x138)
> [<c0661f08>] (__blk_mq_run_hw_queue) from [<c03622a0>] (process_one_work+0x218/0x510)
> [<c03622a0>] (process_one_work) from [<c0363230>] (worker_thread+0x44/0x5bc)
>
> This results in bad data transfers, which ultimately causes the crash.

There are several bugs related with kmap(sg_page(sg)), such as:

sdhci_kmap_atomic()
tmio_mmc_kmap_atomic()
wbsd_map_sg()

Thanks,
Ming Lei

  reply	other threads:[~2019-04-19  2:27 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-08 10:46 avoid calling nth_page in the block I/O path Christoph Hellwig
2019-04-08 10:46 ` [PATCH 1/5] block: rewrite blk_bvec_map_sg to avoid a nth_page call Christoph Hellwig
2019-04-08 14:03   ` Johannes Thumshirn
2019-04-08 22:04   ` Bart Van Assche
2019-04-08 22:51   ` Ming Lei
2019-04-15 19:44   ` Guenter Roeck
2019-04-15 20:52     ` Christoph Hellwig
2019-04-15 21:07       ` Guenter Roeck
2019-04-16  6:33         ` Christoph Hellwig
2019-04-16 14:09           ` Guenter Roeck
2019-04-16 17:08           ` Guenter Roeck
2019-04-16 17:10             ` Christoph Hellwig
2019-04-16 17:51               ` Guenter Roeck
2019-04-17  5:27                 ` Christoph Hellwig
2019-04-17 13:42                   ` Guenter Roeck
2019-04-17 21:59                   ` Guenter Roeck
2019-04-19  2:27                     ` Ming Lei [this message]
2019-04-19  2:36                       ` Ming Lei
2019-04-08 10:46 ` [PATCH 2/5] block: refactor __bio_iov_bvec_add_pages Christoph Hellwig
2019-04-08 11:07   ` Johannes Thumshirn
2019-04-08 22:06   ` Bart Van Assche
2019-04-08 10:46 ` [PATCH 3/5] block: don't allow multiple bio_iov_iter_get_pages calls per bio Christoph Hellwig
2019-04-08 11:13   ` Johannes Thumshirn
2019-04-08 22:17   ` Bart Van Assche
2019-04-09 10:05     ` Christoph Hellwig
2019-04-08 10:46 ` [PATCH 4/5] block: change how we get page references in bio_iov_iter_get_pages Christoph Hellwig
2019-04-08 10:46 ` [PATCH 5/5] block: only allow contiguous page structs in a bio_vec Christoph Hellwig
2019-04-09 16:15 ` avoid calling nth_page in the block I/O path Jens Axboe
2019-04-11  6:23 avoid calling nth_page in the block I/O path v2 Christoph Hellwig
2019-04-11  6:23 ` [PATCH 1/5] block: rewrite blk_bvec_map_sg to avoid a nth_page call Christoph Hellwig

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