Messages in this thread | | | Date | Fri, 29 Sep 2006 01:03:39 +0200 | From | Pavel Machek <> | Subject | Re: [PATCH -mm 1/3] swsusp: Add ioctl for swap files support |
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Hi!
> On Fri, 29 Sep 2006 00:13:38 +0200 > "Rafael J. Wysocki" <rjw@sisk.pl> wrote: > > > To be able to use swap files as suspend storage from the userland suspend > > tools we need an additional ioctl() that will allow us to provide the kernel > > with both the swap header's offset and the identification of the resume > > partition. > > > > The new ioctl() should be regarded as a replacement for the > > SNAPSHOT_SET_SWAP_FILE ioctl() that from now on will be considered as > > obsolete, but has to stay for backwards compatibility of the interface. > > > > + > > +/* > > + * This structure is used to pass the values needed for the identification > > + * of the resume swap area from a user space to the kernel via the > > + * SNAPSHOT_SET_SWAP_AREA ioctl > > + */ > > +struct resume_swap_area { > > + u_int16_t dev; > > + loff_t offset; > > +} __attribute__((packed));
> > hmm. Asking the compiler to pack 16-bit and 64-bit quantities in this > manner is a bit risky. I guess it'll do the right thing, consistently, > across all compiler versions and vendors and 32-bit-on-64-bit-kernel, etc. > > But from a defensiveness/paranoia POV it'd be better to use a u32 here, I > suspect. (Will access to that loff_t cause an alignment trap on ia64? Any > other CPUs? Dunno).
Perhaps just loff_t offset; u32 dev; ? If 64-bit variable is first, we should avoid most problems, no? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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