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[124.171.83.152]) by smtp.gmail.com with ESMTPSA id h4sm612040pjq.55.2020.06.22.18.12.25 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 22 Jun 2020 18:12:28 -0700 (PDT) Subject: Re: [PATCH 3/4] powerpc/pseries/iommu: Move window-removing part of remove_ddw into remove_dma_window To: Leonardo Bras , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Thiago Jung Bauermann , Ram Pai Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Oliver References: <20200619050619.266888-1-leobras.c@gmail.com> <20200619050619.266888-4-leobras.c@gmail.com> <51201582-efe5-85df-7e65-a998e91ab63f@ozlabs.ru> From: Alexey Kardashevskiy Autocrypt: addr=aik@ozlabs.ru; keydata= mQINBE+rT0sBEADFEI2UtPRsLLvnRf+tI9nA8T91+jDK3NLkqV+2DKHkTGPP5qzDZpRSH6mD EePO1JqpVuIow/wGud9xaPA5uvuVgRS1q7RU8otD+7VLDFzPRiRE4Jfr2CW89Ox6BF+q5ZPV /pS4v4G9eOrw1v09lEKHB9WtiBVhhxKK1LnUjPEH3ifkOkgW7jFfoYgTdtB3XaXVgYnNPDFo PTBYsJy+wr89XfyHr2Ev7BB3Xaf7qICXdBF8MEVY8t/UFsesg4wFWOuzCfqxFmKEaPDZlTuR 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c7E5M+/NpslPCmYnDjs5qg0/3ihh6XuOGggZQOqrYPC3PnsNs3NxirwOkVPQgO6mXxpuifvJ DG9EMkK8IBXnLulqVk54kf7fE0jT/d8RTtJIA92GzsgdK2rpT1MBKKVffjRFGwN7nQVOzi4T XrB5p+6ML7Bd84xOEGsj/vdaXmz1esuH7BOZAGEZfLRCHJ0GVCSssg== Message-ID: <887bf30e-ae9e-b0cb-0388-dc555692ff0a@ozlabs.ru> Date: Tue, 23 Jun 2020 11:12:22 +1000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23/06/2020 04:59, Leonardo Bras wrote: > Hello Alexey, thanks for the feedback! > > On Mon, 2020-06-22 at 20:02 +1000, Alexey Kardashevskiy wrote: >> >> On 19/06/2020 15:06, Leonardo Bras wrote: >>> Move the window-removing part of remove_ddw into a new function >>> (remove_dma_window), so it can be used to remove other DMA windows. >>> >>> It's useful for removing DMA windows that don't create DIRECT64_PROPNAME >>> property, like the default DMA window from the device, which uses >>> "ibm,dma-window". >>> >>> Signed-off-by: Leonardo Bras >>> --- >>> arch/powerpc/platforms/pseries/iommu.c | 53 +++++++++++++++----------- >>> 1 file changed, 31 insertions(+), 22 deletions(-) >>> >>> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c >>> index 5e1fbc176a37..de633f6ae093 100644 >>> --- a/arch/powerpc/platforms/pseries/iommu.c >>> +++ b/arch/powerpc/platforms/pseries/iommu.c >>> @@ -767,25 +767,14 @@ static int __init disable_ddw_setup(char *str) >>> >>> early_param("disable_ddw", disable_ddw_setup); >>> >>> -static void remove_ddw(struct device_node *np, bool remove_prop) >>> +static void remove_dma_window(struct device_node *pdn, u32 *ddw_avail, >> >> You do not need the entire ddw_avail here, pass just the token you need. > > Well, I just emulated the behavior of create_ddw() and query_ddw() as > both just pass the array instead of the token, even though they only > use a single token. True, there is a pattern. > I think it's to make the rest of the code independent of the design of > the "ibm,ddw-applicable" array, and if it changes, only local changes > on the functions will be needed. The helper removes a window, if you are going to call other operations in remove_dma_window(), then you'll have to change its name ;) >> Also, despite this particular file, the "pdn" name is usually used for >> struct pci_dn (not device_node), let's keep it that way. > > Sure, I got confused for some time about this, as we have: > static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn). > but on *_ddw() we have "struct pci_dn *pdn". True again, not the cleanest style here. > I will also add a patch that renames those 'struct device_node *pdn' to > something like 'struct device_node *parent_dn'. I would not go that far, we (well, Oliver) are getting rid of many occurrences of pci_dn and Oliver may have a stronger opinion here. > >>> + struct property *win) >>> { >>> struct dynamic_dma_window_prop *dwp; >>> - struct property *win64; >>> - u32 ddw_avail[3]; >>> u64 liobn; >>> - int ret = 0; >>> - >>> - ret = of_property_read_u32_array(np, "ibm,ddw-applicable", >>> - &ddw_avail[0], 3); >>> - >>> - win64 = of_find_property(np, DIRECT64_PROPNAME, NULL); >>> - if (!win64) >>> - return; >>> - >>> - if (ret || win64->length < sizeof(*dwp)) >>> - goto delprop; >>> + int ret; >>> >>> - dwp = win64->value; >>> + dwp = win->value; >>> liobn = (u64)be32_to_cpu(dwp->liobn); >>> >>> /* clear the whole window, note the arg is in kernel pages */ >>> @@ -793,24 +782,44 @@ static void remove_ddw(struct device_node *np, bool remove_prop) >>> 1ULL << (be32_to_cpu(dwp->window_shift) - PAGE_SHIFT), dwp); >>> if (ret) >>> pr_warn("%pOF failed to clear tces in window.\n", >>> - np); >>> + pdn); >>> else >>> pr_debug("%pOF successfully cleared tces in window.\n", >>> - np); >>> + pdn); >>> >>> ret = rtas_call(ddw_avail[2], 1, 1, NULL, liobn); >>> if (ret) >>> pr_warn("%pOF: failed to remove direct window: rtas returned " >>> "%d to ibm,remove-pe-dma-window(%x) %llx\n", >>> - np, ret, ddw_avail[2], liobn); >>> + pdn, ret, ddw_avail[2], liobn); >>> else >>> pr_debug("%pOF: successfully removed direct window: rtas returned " >>> "%d to ibm,remove-pe-dma-window(%x) %llx\n", >>> - np, ret, ddw_avail[2], liobn); >>> + pdn, ret, ddw_avail[2], liobn); >>> +} >>> + >>> +static void remove_ddw(struct device_node *np, bool remove_prop) >>> +{ >>> + struct property *win; >>> + u32 ddw_avail[3]; >>> + int ret = 0; >>> + >>> + ret = of_property_read_u32_array(np, "ibm,ddw-applicable", >>> + &ddw_avail[0], 3); >>> + if (ret) >>> + return; >>> + >>> + win = of_find_property(np, DIRECT64_PROPNAME, NULL); >>> + if (!win) >>> + return; >>> + >>> + if (win->length >= sizeof(struct dynamic_dma_window_prop)) >> >> Any good reason not to make it "=="? Is there something optional or we >> expect extension (which may not grow from the end but may add cells in >> between). Thanks, > > Well, it comes from the old behavior of remove_ddw(): > - if (ret || win64->length < sizeof(*dwp)) > - goto delprop; > As I reversed the logic from 'if (test) go out' to 'if (!test) do > stuff', I also reversed (a < b) to !(a < b) => (a >= b). > > I have no problem changing that to '==', but it will produce a > different behavior than before. I missed than, never mind then. > >> >> >>> + remove_dma_window(np, ddw_avail, win); >>> + >>> + if (!remove_prop) >>> + return; >>> >>> -delprop: >>> - if (remove_prop) >>> - ret = of_remove_property(np, win64); >>> + ret = of_remove_property(np, win); >>> if (ret) >>> pr_warn("%pOF: failed to remove direct window property: %d\n", >>> np, ret); >>> > > Best regards, > Leonardo > -- Alexey