Date: Tue, 16 Nov 2010 01:33:53 +0100 From: Ivan Voras <ivoras@freebsd.org> To: Luigi Rizzo <luigi@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r215178 - in head: lib/libc/sys sys/kern sys/sys Message-ID: <AANLkTimbF45rHrP9FXc0Fr7j%2Bq_NYa8haXpjYSWWiYc-@mail.gmail.com> In-Reply-To: <20101115171016.GB20524@onelab2.iet.unipi.it> References: <201011121302.oACD2Qjt009385@svn.freebsd.org> <AANLkTinpfy-V79k0mgezJV6QpuUWMG3uOZ0hTY2tN4Rf@mail.gmail.com> <20101115171016.GB20524@onelab2.iet.unipi.it>
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On 15 November 2010 18:10, Luigi Rizzo <rizzo@iet.unipi.it> wrote: > 2. [generic] passing pointers between userland and kernel > requires remapping the pointer when going up or down. > As the mapping would be application specific, i don't > see much use in allowing room for a pointer without kernel code > to map userland <-> kernel pointers. I'm not thinking of passing a *working* pointer into the kernel but used as a cookie, similar to how it's used in kqueue: the intention being the application can send and get a pointer which means something to the application, not something usable to the kernel. Without using intptr_t, if an application wants to hang a structure on the cookie, it needs to maintain its own translation table (index-to-pointer).
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