On 2023/3/24 0:25, John Garry wrote:
On 23/03/2023 13:13, haowenchao (C) wrote:
On 2023/3/23 20:40, John Garry wrote:
On 23/03/2023 11:55, Wenchao Hao wrote:
The original error injection mechanism was based on scsi_host which
could not inject fault for a single SCSI device.
This patchset provides the ability to inject errors for a single
SCSI device. Now we supports inject timeout errors, queuecommand
errors, and hostbyte, driverbyte, statusbyte, and sense data for
specific SCSI Command.
There is already a basic mechanism to generate errors - like timeouts - on "nth" command. Can you say why you want this new interface? What special scenarios are you trying to test/validate (which could not be achieved based on the current mechanism)?
I am testing a new error handle policy which is based on single scsi_device
without set host to RECOVERY. So I need a method to generate errors for
single SCSI devices.
While we can not generate errors for single device with current mechanism
because it is designed for host-wide error generation.
With this series we would have 2x methods to inject errors, which is less than ideal, and they seem to possibly conflict as well, e.g. I set timeout for nth command via current interface and then use the new interface to set timeout for some other cadence. What behavior to expect ...?
I did not take this issue in consideration. I now assume the users would
not use these 2 methods at same time.
What's more, I don not know where to write the usage of this newly added
interface, maybe we can explain these in doc?
sysfs entries are described in Documentation/ABI, but please don't add elaborate programming interfaces in sysfs files (like in these patches) - a sysfs file should be just for reading or writing a single value
If sysfs is not recommended, what about proc?
I'm not saying that I am a huge fan of the current inject mechanism, but at the very least you need to provide more justification for this series.
The first patch add an sysfs interface to add and inquiry single
device's error injection info; the second patch defined how to remove
an injection which has been added. The following 3 patches use the
injection info and generate the related error type.
Wenchao Hao (5):
scsi:scsi_debug: Add sysfs interface to manage scsi devices' error
injection
scsi:scsi_debug: Define grammar to remove added error injection
scsi:scsi_debug: timeout command if the error is injected
scsi:scsi_debug: Return failed value if the error is injected
scsi:scsi_debug: set command's result and sense data if the error is
injected
drivers/scsi/scsi_debug.c | 296 ++++++++++++++++++++++++++++++++++++++
1 file changed, 296 insertions(+)
