Date: Wed, 27 Jun 2018 12:22:42 +0530 From: Pratyush Yadav <pratyush@freebsd.org> To: freebsd-hackers@freebsd.org Cc: freebsd-arch@freebsd.org, =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= <royger@freebsd.org>, Edward Napierala <trasz@freebsd.org>, Akshay Jaggi <jaggi@freebsd.org> Subject: Can bus_dmamap_unload() be called before the load completes? Message-ID: <CA%2BX=3TJHD3Xo-ZtoL=s5sKCAWrFXeF1ocrJttn6ypcYLZJDqMA@mail.gmail.com>
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Hi everyone, I am currently working on an alternate bus_dma(9) implementation for use with the Xen drivers [0]. I have a question regarding how the bus_dma(9) interface is expected to be used: If the load is deferred because of a shortage of resources, is it "legal" to call unload before the load completes? In my implementation, if unload is called while the load is waiting for resources, it would result in a segmentation fault and leak memory. Do I need to handle that possibility, or is it ok to assume that unload won't be called before the load completes? Regards, Pratyush Yadav [0] https://wiki.freebsd.org/SummerOfCode2018Projects/ImportXenbus_dmaFromOpenBSD
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