On Wed, 27 Sep 2006 21:48:42 -0400 Jeff Garzik <jeff@xxxxxxxxxx> wrote: > The usage model should not be _forced_ upon the caller, since it might > not be needed. IMO: tough titty. This isn't some random crappy perl script. Nor is it even some random crappy sound card driver. This is our scsi stack. The heart of our MissionCriticalEnterpriseReadyCoreOfAThirtyBillionDollarIndustry operating system. Picture yourself telling a Fortune 100 CTO why his kernel is cheerily discarding errors (and hence his reliability and possibly data) all over the place. Take a peek at spi_dv_device() and its callees... I was astonished at the number of ignored errors all over the sysfs/driver-model code. And that's only there to detect programming errors. That's nothing compared to these bugs. Discarding already-detected hardware or software errors in the storage stack is toe-curlingly lame, and completely trumps the inconvenience of developers seeing a few warnings, or having to put artificial warning shutter-uppers in a few places. Now I'm sure I'm about to be flooded with long-winded explanations about why all of this can never happen. But y'know what? I don't care. Hardware errors can sometimes happen. As can programming errors, as can memory-corruption and dropped-bit errors and all the other things we regularly see. The kernel should be robust in the presence of unexpected events. *Particularly* those parts which are handling storage. Any void-returning function in a driver or a mid-layer is a huge red flag. And it's not sufficient to say "gee, I can't think of any reason why this handler would return an error, so I'll design its callers to assume that". It is _much_ better to design the callers to assume that callees _can_ fail, and to stick the `return 0;' into the terminal callee. Because things can change. There, I feel better now. If you want to see the other warnings, set CONFIG_ENABLE_MUST_CHECK=n. - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
