On Tue, 2006-05-16 at 11:05 -0700, Luben Tuikov wrote: > Let me now explain, after your twice objecting in the same way to the > patch: > > You CANNOT call the done() function on a command (and return DID_FAILED) > because this terminates the nexus established when queuecommand() got called, > and then later try to "recover" the command as you're suggesting here and > in the thread I included the link to above. > > That is, when queuecommand() got called, the nexus is now with the driver, > and/or the FW and/or the transport and/or the device, _depending_ on how > far the driver/fw/transport/device got to executing the command. > > The only way to _terminate_ the command nexus with the driver is by > calling done(), which means, > > "I (the driver) am completely done with this command, I'm not referencing it, > nor will you hear about it any more, and I'm giving it back to you, SCSI Core." > > This is _basic_ SCSI knowledge. > > For this reason, "scsi_req_abort_cmd()" needs to exist. It causes recovery > of the command to begin, in a universal way, independent of if the timeout > and/or the eh had been differently defined. As well as, scsi_req_abort_cmd(), > can be called by either SCSI Core or a driver, from any context, without worrying > where the command is. The only current proposed user of this is libata-eh. If you look, you'll see the caller is from ata_qc_complete() which is only called *after* the nexus is terminated. James - : 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
