From: Christoph Hellwig <hch@infradead.org>
To: Sherry Sun <sherry.sun@nxp.com>
Cc: hch@infradead.org, sudeep.dutt@intel.com,
ashutosh.dixit@intel.com, arnd@arndb.de,
gregkh@linuxfoundation.org, kishon@ti.com,
lorenzo.pieralisi@arm.com, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, linux-imx@nxp.com
Subject: Re: [PATCH V2 3/4] misc: vop: simply return the saved dma address instead of virt_to_phys
Date: Tue, 29 Sep 2020 11:26:43 +0100 [thread overview]
Message-ID: <20200929102643.GC7784@infradead.org> (raw)
In-Reply-To: <20200929084425.24052-4-sherry.sun@nxp.com>
On Tue, Sep 29, 2020 at 04:44:24PM +0800, Sherry Sun wrote:
> The device page and vring should use consistent memory which are
> allocated by dma_alloc_coherent api, when user space wants to get its
> physical address, virt_to_phys cannot be used, should simply return the
> saved device page dma address by get_dp_dma callback and the vring dma
> address saved in mic_vqconfig.
More importantly you can't just all virt_to_phys on a return value
from dma_alloc_coherent, so this needs to be folded into patch 1.
> if (!offset) {
> - *pa = virt_to_phys(vpdev->hw_ops->get_dp(vpdev));
> + if (vpdev->hw_ops->get_dp_dma)
> + *pa = vpdev->hw_ops->get_dp_dma(vpdev);
> + else {
> + dev_err(vop_dev(vdev), "can't get device page physical address\n");
> + return -EINVAL;
> + }
I don't think we need the NULL check here. Wouldn't it also make sense
to return the virtual and DMA address from ->get_dp instead of adding
another method?
next prev parent reply other threads:[~2020-09-29 10:26 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-29 8:44 [PATCH V2 0/4] Change vring space from nomal memory to dma coherent memory Sherry Sun
2020-09-29 8:44 ` [PATCH V2 1/4] misc: vop: change the way of allocating vring Sherry Sun
2020-09-29 10:23 ` Christoph Hellwig
2020-09-29 13:02 ` Sherry Sun
2020-09-29 8:44 ` [PATCH V2 2/4] misc: vop: do not allocate and reassign the used ring Sherry Sun
2020-09-29 10:24 ` Christoph Hellwig
2020-09-29 13:02 ` Sherry Sun
2020-09-29 14:28 ` David Laight
2020-09-29 8:44 ` [PATCH V2 3/4] misc: vop: simply return the saved dma address instead of virt_to_phys Sherry Sun
2020-09-29 10:26 ` Christoph Hellwig [this message]
2020-09-29 13:10 ` Sherry Sun
2020-09-29 18:11 ` Christoph Hellwig
2020-09-30 7:30 ` Sherry Sun
2020-10-05 13:42 ` Christoph Hellwig
2020-09-29 8:44 ` [PATCH V2 4/4] misc: vop: mapping kernel memory to user space as noncached Sherry Sun
2020-09-29 10:28 ` Christoph Hellwig
2020-09-29 13:12 ` Sherry Sun
2020-09-29 15:39 ` David Laight
2020-10-13 2:02 ` Sherry Sun
2020-10-20 1:33 ` Sherry Sun
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