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From: Al Viro <[email protected]>
To: Keith Busch <[email protected]>
Cc: [email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected], Keith Busch <[email protected]>
Subject: Re: [PATCH 4/5] io_uring: add support for dma pre-mapping
Date: Wed, 27 Jul 2022 15:11:05 +0100	[thread overview]
Message-ID: <YuFHeT0UaQsYssin@ZenIV> (raw)
In-Reply-To: <[email protected]>

On Tue, Jul 26, 2022 at 10:38:13AM -0700, Keith Busch wrote:

> +	file = fget(map.fd);
> +	if (!file)
> +		return -EBADF;
> +
> +	if (S_ISBLK(file_inode(file)->i_mode))
> +		bdev = I_BDEV(file->f_mapping->host);
> +	else if (S_ISREG(file_inode(file)->i_mode))
> +		bdev = file->f_inode->i_sb->s_bdev;
> +	else
> +		return -EOPNOTSUPP;
> +
> +	for (i = map.buf_start; i < map.buf_end; i++) {
> +		struct io_mapped_ubuf *imu = ctx->user_bufs[i];
> +		void *tag;
> +
> +		if (imu->dma_tag) {
> +			ret = -EBUSY;
> +			goto err;
> +		}
> +
> +		tag = block_dma_map(bdev, imu->bvec, imu->nr_bvecs);
> +		if (IS_ERR(tag)) {
> +			ret = PTR_ERR(tag);
> +			goto err;
> +		}
> +
> +		imu->dma_tag = tag;
> +		imu->dma_file = file;
> +		imu->bdev = bdev;
> +	}
> +
> +	fput(file);

This, BTW, is completely insane - what happens if you follow that
with close(map.fd)?  A bunch of dangling struct file references?

I really don't understand what you are trying to do here.

  parent reply	other threads:[~2022-07-27 14:11 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-26 17:38 [PATCH 0/5] dma mapping optimisations Keith Busch
2022-07-26 17:38 ` [PATCH 1/5] blk-mq: add ops to dma map bvec Keith Busch
2022-07-26 17:38 ` [PATCH 2/5] iov_iter: introduce type for preregistered dma tags Keith Busch
2022-07-26 23:10   ` Al Viro
2022-07-27 13:52     ` Keith Busch
2022-07-26 17:38 ` [PATCH 3/5] block: add dma tag bio type Keith Busch
2022-07-26 17:38 ` [PATCH 4/5] io_uring: add support for dma pre-mapping Keith Busch
2022-07-26 23:12   ` Al Viro
2022-07-27 13:58     ` Keith Busch
2022-07-27 14:04       ` Al Viro
2022-07-27 15:04         ` Keith Busch
2022-07-27 22:32           ` Dave Chinner
2022-07-27 23:00             ` Keith Busch
2022-07-28  2:35               ` Dave Chinner
2022-07-28 13:25                 ` Keith Busch
2022-07-27 14:11   ` Al Viro [this message]
2022-07-27 14:48     ` Keith Busch
2022-07-27 15:26       ` Al Viro
2022-07-26 17:38 ` [PATCH 5/5] nvme-pci: implement dma_map support Keith Busch

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