From: Leon Romanovsky <leon@kernel.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: Keith Busch <kbusch@kernel.org>, Christoph Hellwig <hch@lst.de>,
Sagi Grimberg <sagi@grimberg.me>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-nvme@lists.infradead.org
Subject: Re: [PATCH v4 0/2] block: Enable proper MMIO memory handling for P2P DMA
Date: Fri, 14 Nov 2025 10:16:23 +0200 [thread overview]
Message-ID: <20251114081623.GB147495@unreal> (raw)
In-Reply-To: <d1641814-5ef8-4ccd-8a41-42bf99a61d0d@kernel.dk>
On Thu, Nov 13, 2025 at 01:40:50PM -0700, Jens Axboe wrote:
> On 11/13/25 12:52 PM, Keith Busch wrote:
> > On Thu, Nov 13, 2025 at 10:45:53AM -0700, Jens Axboe wrote:
> >> I took a look, and what happens here is that iter.p2pdma.map is 0 as it
> >> never got set to anything. That is the same as PCI_P2PDMA_MAP_UNKNOWN,
> >> and hence we just end up in a BLK_STS_RESOURCE. First of all, returning
> >> BLK_STS_RESOURCE for that seems... highly suspicious. That should surely
> >> be a fatal error. And secondly, this just further backs up that there's
> >> ZERO testing done on this patchset at all. WTF?
> >>
> >> FWIW, the below makes it boot just fine, as expected, as a default zero
> >> filled iter then matches the UNKNOWN case.
> >
> > I think this must mean you don't have CONFIG_PCI_P2PDMA enabled. The
>
> Right, like most normal people :-)
It depends how you are declaring normal people :).
In my Fedora OS, installed on my laptop, CONFIG_PCI_P2PDMA is enabled by default.
https://src.fedoraproject.org/rpms/kernel/blob/rawhide/f/kernel-x86_64-fedora.config#_5567
and in RHEL too
https://src.fedoraproject.org/rpms/kernel/blob/rawhide/f/kernel-x86_64-rhel.config#_4964
Thanks
next prev parent reply other threads:[~2025-11-14 8:16 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-12 19:48 [PATCH v4 0/2] block: Enable proper MMIO memory handling for P2P DMA Leon Romanovsky
2025-11-12 19:48 ` [PATCH v4 1/2] nvme-pci: migrate to dma_map_phys instead of map_page Leon Romanovsky
2025-11-12 23:57 ` Chaitanya Kulkarni
2025-11-12 19:48 ` [PATCH v4 2/2] block-dma: properly take MMIO path Leon Romanovsky
2025-11-12 20:00 ` Keith Busch
2025-11-12 23:57 ` Chaitanya Kulkarni
2025-11-13 16:39 ` [PATCH v4 0/2] block: Enable proper MMIO memory handling for P2P DMA Jens Axboe
2025-11-13 17:12 ` Jens Axboe
2025-11-13 17:45 ` Jens Axboe
2025-11-13 19:50 ` Leon Romanovsky
2025-11-13 20:03 ` Keith Busch
2025-11-13 20:13 ` Leon Romanovsky
2025-11-13 20:40 ` Leon Romanovsky
2025-11-13 20:43 ` Jens Axboe
2025-11-14 8:13 ` Leon Romanovsky
2025-11-13 19:52 ` Keith Busch
2025-11-13 20:40 ` Jens Axboe
2025-11-14 8:16 ` Leon Romanovsky [this message]
2025-11-14 12:08 ` Jens Axboe
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