Messages in this thread | | | Date | Thu, 12 Oct 2023 09:55:14 -0700 | From | Saeed Mahameed <> | Subject | Re: [PATCH net v3] net/mlx5: fix calling mlx5_cmd_init() before DMA mask is set |
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On 12 Oct 13:39, Niklas Schnelle wrote: >On Thu, 2023-10-12 at 12:53 +0200, Niklas Schnelle wrote: >> On Wed, 2023-10-11 at 11:56 -0700, Saeed Mahameed wrote: >> > On 11 Oct 11:20, Saeed Mahameed wrote: >> > > On 11 Oct 09:57, Niklas Schnelle wrote: >> > > > Since commit 06cd555f73ca ("net/mlx5: split mlx5_cmd_init() to probe and >> > > > reload routines") mlx5_cmd_init() is called in mlx5_mdev_init() which is >> > > > called in probe_one() before mlx5_pci_init(). This is a problem because >> > > > mlx5_pci_init() is where the DMA and coherent mask is set but >> > > > mlx5_cmd_init() already does a dma_alloc_coherent(). Thus a DMA >> > > > allocation is done during probe before the correct mask is set. This >> > > > causes probe to fail initialization of the cmdif SW structs on s390x >> > > > after that is converted to the common dma-iommu code. This is because on >> > > > s390x DMA addresses below 4 GiB are reserved on current machines and >> > > > unlike the old s390x specific DMA API implementation common code >> > > > enforces DMA masks. >> > > > >> > > > Fix this by moving set_dma_caps() out of mlx5_pci_init() and into >> > > > probe_one() before mlx5_mdev_init(). To match the overall naming scheme >> > > > rename it to mlx5_dma_init(). >> > > >> > > How about we just call mlx5_pci_init() before mlx5_mdev_init(), instead of >> > > breaking it apart ? >> > >> > I just posted this RFC patch [1]: >> >> This patch works to solve the problem as well. >> >> > >> > I am working in very limited conditions these days, and I don't have strong >> > opinion on which approach to take, Leon, Niklas, please advise. >> > >> > The three possible solutions: >> > >> > 1) mlx5_pci_init() before mlx5_mdev_init(), I don't think enabling pci >> > before initializing cmd dma would be a problem. >> > >> > 2) This patch. >> > >> > 3) Shay's patch from the link below: >> > [1] https://patchwork.kernel.org/project/netdevbpf/patch/20231011184511.19818-1-saeed@kernel.org/ >> > >> > Thanks, >> > Saeed. >> >> My first gut feeling was option 1) but I'm just as happy with 2) or 3). >> For me option 2 is the least invasive but not by much. >> >> For me the important thing is what Jason also said yesterday. We need >> to merge something now to unbreak linux-next on s390x and to make sure >> we don't end up with a broken v6.7-rc1. This is already hampering our >> CI tests with linux-next. So let's do whatever can be merged the >> quickest and then feel free to do any refactoring ideas that this >> discussion might have spawned on top of that. My guess for this >> criteria would be 2). >> >> Thanks, >> Niklas >> > >Looking closer at the patch from Shay I do like that it changes the >order in the disable/tear down path too. So since that also fixes a PPC >issue I guess that may indeed be the best solution if we can get it >merged quickly. I'll comment with my Tested-by there too. >
Ack, will take Shay's patch then, Will add your Test-by and Reviewed-by.
>Thanks, >Niklas
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