On Wed, 29 Nov 2006 16:47:47 -0800, Zach Brown <[EMAIL PROTECTED]> wrote:
> On Nov 29, 2006, at 2:32 AM, Sébastien Dugué wrote: > > > compat_sys_io_submit() cleanup > > > > > > Cleanup compat_sys_io_submit by duplicating some of the native > > syscall > > logic in the compat layer and directly calling io_submit_one() instead > > of fooling the syscall into thinking it is called from a native 64-bit > > caller. > > > > This is needed for the completion notification patch to avoid having > > to rewrite each iocb on the caller stack for sys_io_submit() to > > find the > > sigevents. > > You could explicitly mention that this eliminates: > > - the overhead of copying nr pointers on the userspace caller's stack > > - the arbitrary PAGE_SIZE/(sizeof(void *)) limit on the number of > iocbs that can be submitted > > Those alone make this worth merging. Right, will add. > > > + if (unlikely(!access_ok(VERIFY_READ, iocb, (nr * sizeof(u32))))) > > + return -EFAULT; > > I'm glad you got that right :) I no doubt would have initially > hoisted these little checks into a shared helper function and missed > that detail of getting the size of the access_ok() right in the > compat case. Thanks. > > > + put_ioctx(ctx); > > + > > + return i? i: ret; > > sys_io_getevents() reads: uh! ^^^^^^^^^ you must be meaning sys_io_submit()? > > put_ioctx(ctx); > return i ? i : ret; > > So while this compat_sys_io_submit() logic seems fine and I would be > comfortable with it landing as-is, I'd also appreciate it if we > didn't introduce differences between the two functions when it seems > just as easy to make them the same. (That chunk is just one > example. There's whitespace, missing unlikely()s, etc). > OK, will fix. Thanks, Sébastien. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
