[PATCH V2 1/1] nvme: Add verbose error logging

[Alan Adamson]

> On Dec 27, 2021, at 8:07 AM, Keith Busch <kbusch at kernel.org> wrote:
> 
> On Thu, Dec 23, 2021 at 01:57:26PM -0800, Alan Adamson wrote:
>> +
>> +static const char * const nvme_errors[] = {
>> +	"Success",
>> +	"Invalid Command Opcode",
>> +	"Invalid Field in Command",
>> +	"Command ID Conflict",
>> +	"Data Transfer Error",
>> +	"Commands Aborted due to Power Loss Notification",
>> +	"Internal Error",
>> +	"Command Abort Requested",
>> +	"Command Aborted due to SQ Deletion",
>> +	"Command Aborted due to Failed Fused Command",
>> +	"Command Aborted due to Missing Fused Command",
>> +	"Invalid Namespace or Format",
>> +	"Command Sequence Error",
>> +	"Invalid SGL Segment Descriptor",
>> +	"Invalid Number of SGL Descriptors",
>> +	"Data SGL Length Invalid",
>> +	"Metadata SGL Length Invalid",
>> +	"SGL Descriptor Type Invalid",
>> +	"Invalid Use of Controller Memory Buffer",
>> +	"PRP Offset Invalid",
>> +	"Atomic Write Unit Exceeded",
>> +	"Operation Denied",
>> +	"SGL Offset Invalid",
>> +	"Reserved",
>> +	"Host Identifier Inconsistent Format",
>> +	"Keep Alive Timeout Expired",
>> +	"Keep Alive Timeout Invalid",
>> +	"Command Aborted due to Preempt and Abort",
>> +	"Sanitize Failed",
>> +	"Sanitize In Progress",
>> +	"SGL Data Block Granularity Invalid",
>> +	"Command Not Supported for Queue in CMB",
>> +	"Namespace is Write Protected",
>> +	"Command Interrupted",
>> +	"Transient Transport Error",
>> +	NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
> 
> Tracking these NULL's is going to be problematic and error prone.

I don’t disagree, definitely wasn’t fun putting them in there:)

If we don’t define the NULLs, what happens if the hardware responds with a undefined error status? 
We will attempt to log a undefined/non-string.

Alan

> 
> I recommend indexing the strings as you define them. For example:
> 
> static const char * const nvme_errors[] = {
> 	[NVME_SC_SUCCESS] = "Success",
> 	[NVME_SC_INVALID_OPCODE] = "Invalid Command Opcode",
> 
> etc...
> 
> Then you don't need to bother tracking the undefined indexes or making
> sure everything is in order.