On Tue, May 27, 2014 at 09:49:48AM +0200, Bart Van Assche wrote: > > I don't see the value of patches 2,3 they're checking for an impossible > > condition ... why might it be possible? > > When reading the source code in scsi_error.c it's easy to overlook that > scmd_eh_abort_handler(), scsi_abort_command() and scsi_eh_scmd_add() are > all invoked for requests in which the REQ_ATOM_COMPLETE bit has been > set. Although it is possible to mention this as a comment above these > functions, such comments are not checked at runtime. It would require > additional work from the reader to verify whether or not such source > code comments are up to date. However, the condition inside a > WARN_ON_ONCE() statement is checked every time the code is executed. > Hence my preference for a WARN_ON_ONCE() statement instead of writing > down somewhere that these three functions operate on requests in which > the REQ_ATOM_COMPLETE bit has been set.
I really do like the REQ_ATOM_COMPLETE asserts - as experience tells these kinds of assumptions are best checked, otherwise they will unintentionally be violated. I'm less excited about the list walk I have to say, as the overhead is getting fairly large for a simple assertation. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
