From: Joerg Roedel <joro@8bytes.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Robin Murphy <robin.murphy@arm.com>,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 3/4] dma-mapping: add a dma_ops_bypass flag to struct device
Date: Sat, 18 Apr 2020 14:42:05 +0200 [thread overview]
Message-ID: <20200418124205.GD6113@8bytes.org> (raw)
In-Reply-To: <20200414122506.438134-4-hch@lst.de>
Hi Christoph,
On Tue, Apr 14, 2020 at 02:25:05PM +0200, Christoph Hellwig wrote:
> +static inline bool dma_map_direct(struct device *dev,
> + const struct dma_map_ops *ops)
> +{
> + if (likely(!ops))
> + return true;
> + if (!dev->dma_ops_bypass)
> + return false;
> +
> + return min_not_zero(*dev->dma_mask, dev->bus_dma_limit) >=
> + dma_direct_get_required_mask(dev);
Why is the dma-mask check done here? The dma-direct code handles memory
outside of the devices dma-mask with swiotlb, no?
I also don't quite get what the difference between setting the
dma_ops_bypass flag non-zero and setting ops to NULL is.
Joerg
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <joro@8bytes.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Robin Murphy <robin.murphy@arm.com>,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
linuxppc-dev@lists.ozlabs.org,
Lu Baolu <baolu.lu@linux.intel.com>
Subject: Re: [PATCH 3/4] dma-mapping: add a dma_ops_bypass flag to struct device
Date: Sat, 18 Apr 2020 14:42:05 +0200 [thread overview]
Message-ID: <20200418124205.GD6113@8bytes.org> (raw)
In-Reply-To: <20200414122506.438134-4-hch@lst.de>
Hi Christoph,
On Tue, Apr 14, 2020 at 02:25:05PM +0200, Christoph Hellwig wrote:
> +static inline bool dma_map_direct(struct device *dev,
> + const struct dma_map_ops *ops)
> +{
> + if (likely(!ops))
> + return true;
> + if (!dev->dma_ops_bypass)
> + return false;
> +
> + return min_not_zero(*dev->dma_mask, dev->bus_dma_limit) >=
> + dma_direct_get_required_mask(dev);
Why is the dma-mask check done here? The dma-direct code handles memory
outside of the devices dma-mask with swiotlb, no?
I also don't quite get what the difference between setting the
dma_ops_bypass flag non-zero and setting ops to NULL is.
Joerg
WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <joro@8bytes.org>
To: Christoph Hellwig <hch@lst.de>
Cc: iommu@lists.linux-foundation.org,
Alexey Kardashevskiy <aik@ozlabs.ru>,
linuxppc-dev@lists.ozlabs.org,
Lu Baolu <baolu.lu@linux.intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Robin Murphy <robin.murphy@arm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/4] dma-mapping: add a dma_ops_bypass flag to struct device
Date: Sat, 18 Apr 2020 14:42:05 +0200 [thread overview]
Message-ID: <20200418124205.GD6113@8bytes.org> (raw)
In-Reply-To: <20200414122506.438134-4-hch@lst.de>
Hi Christoph,
On Tue, Apr 14, 2020 at 02:25:05PM +0200, Christoph Hellwig wrote:
> +static inline bool dma_map_direct(struct device *dev,
> + const struct dma_map_ops *ops)
> +{
> + if (likely(!ops))
> + return true;
> + if (!dev->dma_ops_bypass)
> + return false;
> +
> + return min_not_zero(*dev->dma_mask, dev->bus_dma_limit) >=
> + dma_direct_get_required_mask(dev);
Why is the dma-mask check done here? The dma-direct code handles memory
outside of the devices dma-mask with swiotlb, no?
I also don't quite get what the difference between setting the
dma_ops_bypass flag non-zero and setting ops to NULL is.
Joerg
next prev parent reply other threads:[~2020-04-18 12:42 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-14 12:25 generic DMA bypass flag v3 Christoph Hellwig
2020-04-14 12:25 ` Christoph Hellwig
2020-04-14 12:25 ` Christoph Hellwig
2020-04-14 12:25 ` [PATCH 1/4] dma-mapping: move the remaining DMA API calls out of line Christoph Hellwig
2020-04-14 12:25 ` Christoph Hellwig
2020-04-14 12:25 ` Christoph Hellwig
2020-04-15 2:26 ` Alexey Kardashevskiy
2020-04-15 2:26 ` Alexey Kardashevskiy
2020-04-15 2:26 ` Alexey Kardashevskiy
2020-04-15 6:18 ` Christoph Hellwig
2020-04-15 6:18 ` Christoph Hellwig
2020-04-15 6:18 ` Christoph Hellwig
2020-04-15 11:21 ` Alexey Kardashevskiy
2020-04-15 11:21 ` Alexey Kardashevskiy
2020-04-15 11:21 ` Alexey Kardashevskiy
2020-04-17 7:58 ` Christoph Hellwig
2020-04-17 7:58 ` Christoph Hellwig
2020-04-17 7:58 ` Christoph Hellwig
2020-05-05 4:18 ` Alexey Kardashevskiy
2020-05-05 4:18 ` Alexey Kardashevskiy
2020-05-05 4:18 ` Alexey Kardashevskiy
2020-05-09 8:19 ` Christoph Hellwig
2020-05-09 8:19 ` Christoph Hellwig
2020-05-09 8:19 ` Christoph Hellwig
2020-05-09 14:07 ` Alexey Kardashevskiy
2020-05-09 14:07 ` Alexey Kardashevskiy
2020-05-09 14:07 ` Alexey Kardashevskiy
2020-06-03 4:13 ` Alexey Kardashevskiy
2020-06-03 4:13 ` Alexey Kardashevskiy
2020-06-03 4:13 ` Alexey Kardashevskiy
2020-07-07 0:43 ` Alexey Kardashevskiy
2020-07-07 0:43 ` Alexey Kardashevskiy
2020-07-07 0:43 ` Alexey Kardashevskiy
2020-07-07 14:51 ` Christoph Hellwig
2020-07-07 14:51 ` Christoph Hellwig
2020-07-07 14:51 ` Christoph Hellwig
2020-04-14 12:25 ` [PATCH 2/4] dma-mapping: inline the fast path dma-direct calls Christoph Hellwig
2020-04-14 12:25 ` Christoph Hellwig
2020-04-14 12:25 ` Christoph Hellwig
2020-04-14 12:25 ` [PATCH 3/4] dma-mapping: add a dma_ops_bypass flag to struct device Christoph Hellwig
2020-04-14 12:25 ` Christoph Hellwig
2020-04-14 12:25 ` Christoph Hellwig
2020-04-14 12:47 ` Greg Kroah-Hartman
2020-04-14 12:47 ` Greg Kroah-Hartman
2020-04-14 12:47 ` Greg Kroah-Hartman
2020-04-18 12:42 ` Joerg Roedel [this message]
2020-04-18 12:42 ` Joerg Roedel
2020-04-18 12:42 ` Joerg Roedel
2020-04-19 8:00 ` Christoph Hellwig
2020-04-19 8:00 ` Christoph Hellwig
2020-04-19 8:00 ` Christoph Hellwig
2020-04-19 12:25 ` Joerg Roedel
2020-04-19 12:25 ` Joerg Roedel
2020-04-19 12:25 ` Joerg Roedel
2020-04-19 14:46 ` Alexey Kardashevskiy
2020-04-19 14:46 ` Alexey Kardashevskiy
2020-04-19 14:46 ` Alexey Kardashevskiy
2020-04-14 12:25 ` [PATCH 4/4] powerpc: use the generic dma_ops_bypass mode Christoph Hellwig
2020-04-14 12:25 ` Christoph Hellwig
2020-04-14 12:25 ` Christoph Hellwig
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200418124205.GD6113@8bytes.org \
--to=joro@8bytes.org \
--cc=gregkh@linuxfoundation.org \
--cc=hch@lst.de \
--cc=iommu@lists.linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=robin.murphy@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.