From: Christoph Hellwig <hch@infradead.org>
To: Nilesh Javali <njavali@marvell.com>
Cc: martin.petersen@oracle.com, lduncan@suse.com, cleech@redhat.com,
linux-scsi@vger.kernel.org,
GR-QLogic-Storage-Upstream@marvell.com, jmeneghi@redhat.com
Subject: Re: [PATCH] cnic: change __GFP_COMP allocation method
Date: Mon, 18 Dec 2023 21:58:31 -0800 [thread overview]
Message-ID: <ZYExB52f/iDzD8xL@infradead.org> (raw)
In-Reply-To: <20231219055514.12324-1-njavali@marvell.com>
On Tue, Dec 19, 2023 at 11:25:14AM +0530, Nilesh Javali wrote:
> The dma_alloc_coherent no more provide __GFP_COMP allocation as per commit,
> dma-mapping: reject __GFP_COMP in dma_alloc_attrs, and hence
> instead use __get_free_pages for __GFP_COMP allocation along with
> dma_map_single to get dma address in order to fix page reference counting
> issue caused in iscsiuio mmap.
You can't just do a single map for things mapped to userspace, as that
breaks setups that are not DMA coherent. There was a patch floating
around to explicitly support dma coherent allocations in uio, which is
the right thing to do.
next prev parent reply other threads:[~2023-12-19 5:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-19 5:55 [PATCH] cnic: change __GFP_COMP allocation method Nilesh Javali
2023-12-19 5:58 ` Christoph Hellwig [this message]
2023-12-19 6:16 ` [EXT] " Nilesh Javali
2023-12-21 6:48 ` Christoph Hellwig
2023-12-21 14:33 ` John Meneghini
2023-12-21 17:02 ` Greg KH
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