Date: Fri, 17 Aug 2018 13:21:45 +0530 From: Pratyush Yadav <pratyush@freebsd.org> To: freebsd-hackers@freebsd.org Cc: =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= <royger@freebsd.org> Subject: bus_dma(9): Is it allowed to load an already-loaded map? Message-ID: <CA%2BX=3T%2B%2BDxHtBNZFMp9eFQhCLAPzBbTGr-JDnC4j4C47Mn683Q@mail.gmail.com>
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Hi, I am writing an implementation of the bus_dma(9) interface for use with the Xen drivers, and I have a question: Is it allowed to load a dma map with an active mapping? The bus_dma(9) man page says: map A DMA map without a currently active mapping But, looking at the busdma_bounce (sys/x86/x86/busdma_bounce.c) code, it has no checks against this. On the contrary, it seems to support loading already-loaded maps. Maybe the interface allowed it earlier but removed support later. Or maybe it did not allow this earlier, and now it does, but the man page is just not updated. Can someone familiar with the details of the busdma system confirm? -- Regards, Pratyush Yadav
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