linux-toradex.git/include/scsi/libiscsi.h, branch v6.1

scsi: libiscsi: Improve conn_send_pdu API

2022-06-22T01:19:23+00:00

The conn_send_pdu API is evil in that it returns a pointer to an
iscsi_task, but that task might have been freed already so you can't touch
it. This patch splits the task allocation and transmission, so functions
like iscsi_send_nopout() can access the task before its sent and do
whatever bookkeeping is needed before it is sent.

Link: https://lore.kernel.org/r/20220616224557.115234-10-michael.christie@oracle.com
Reviewed-by: Lee Duncan 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: iscsi: Remove iscsi_get_task back_lock requirement

2022-06-22T01:19:23+00:00

We currently require that the back_lock is held when calling the functions
that manipulate the iscsi_task refcount. The only reason for this is to
handle races where we are handling SCSI-ml EH callbacks and the cmd is
completing at the same time the normal completion path is running, and we
can't return from the EH callback until the driver has stopped accessing
the cmd. Holding the back_lock while also accessing the task->state made it
simple to check that a cmd is completing and also get/put a refcount at the
same time, and at the time we were not as concerned about performance.

The problem is that we don't want to take the back_lock from the xmit path
for normal I/O since it causes contention with the completion path if the
user has chosen to try and split those paths on different CPUs (in this
case abusing the CPUs and ignoring caching improves perf for some uses).

Begins to remove the back_lock requirement for iscsi_get/put_task by
removing the requirement for the get path. Instead of always holding the
back_lock we detect if something has done the last put and is about to call
iscsi_free_task(). A subsequent commit will then allow iSCSI code to do the
last put on a task and only grab the back_lock if the refcount is now zero
and it's going to call iscsi_free_task().

Link: https://lore.kernel.org/r/20220616224557.115234-8-michael.christie@oracle.com
Reviewed-by: Lee Duncan 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: iscsi: Add recv workqueue helpers

2022-06-22T01:19:22+00:00

Add helpers to allow the drivers to run their recv paths from libiscsi's
workqueue.

Link: https://lore.kernel.org/r/20220616224557.115234-3-michael.christie@oracle.com
Reviewed-by: Lee Duncan 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: iscsi: Rename iscsi_conn_queue_work()

2022-06-22T01:19:22+00:00

Rename iscsi_conn_queue_work() to iscsi_conn_queue_xmit() to reflect that
it handles queueing of xmits only.

Link: https://lore.kernel.org/r/20220616224557.115234-2-michael.christie@oracle.com
Reviewed-by: Lee Duncan 
Reviewed-by: Wu Bo 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: iscsi: Fix session removal on shutdown

2022-06-22T01:14:54+00:00

When the system is shutting down, iscsid is not running so we will not get
a response to the ISCSI_ERR_INVALID_HOST error event. The system shutdown
will then hang waiting on userspace to remove the session.

This has libiscsi force the destruction of the session from the kernel when
iscsi_host_remove() is called from a driver's shutdown callout.

This fixes a regression added in qedi boot with commit d1f2ce77638d ("scsi:
qedi: Fix host removal with running sessions") which made qedi use the
common session removal function that waits on userspace instead of rolling
its own kernel based removal.

Link: https://lore.kernel.org/r/20220616222738.5722-7-michael.christie@oracle.com
Fixes: d1f2ce77638d ("scsi: qedi: Fix host removal with running sessions")
Tested-by: Nilesh Javali 
Reviewed-by: Lee Duncan 
Reviewed-by: Nilesh Javali 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: iscsi: Fix harmless double shift bug

2022-04-26T03:23:01+00:00

These flags are supposed to be bit numbers.  Right now they cause a double
shift bug where we use BIT(BIT(2)) instead of BIT(2).  Fortunately, the bit
numbers are small and it's done consistently so it does not cause an issue
at run time.

Link: https://lore.kernel.org/r/YmFyWHf8nrrx+SHa@kili
Fixes: 5bd856256f8c ("scsi: iscsi: Merge suspend fields")
Reviewed-by: Mike Christie 
Reviewed-by: Lee Duncan 
Signed-off-by: Dan Carpenter 
Signed-off-by: Martin K. Petersen

scsi: iscsi: Fix NOP handling during conn recovery

2022-04-12T02:09:35+00:00

If a offload driver doesn't use the xmit workqueue, then when we are doing
ep_disconnect libiscsi can still inject PDUs to the driver. This adds a
check for if the connection is bound before trying to inject PDUs.

Link: https://lore.kernel.org/r/20220408001314.5014-9-michael.christie@oracle.com
Tested-by: Manish Rangankar 
Reviewed-by: Lee Duncan 
Reviewed-by: Chris Leech 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: iscsi: Merge suspend fields

2022-04-12T02:09:35+00:00

Move the tx and rx suspend fields into one flags field.

Link: https://lore.kernel.org/r/20220408001314.5014-8-michael.christie@oracle.com
Tested-by: Manish Rangankar 
Reviewed-by: Lee Duncan 
Reviewed-by: Chris Leech 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: iscsi: Drop temp workq_name

2022-03-02T04:56:28+00:00

When the workqueue code was created it didn't allow variable args so we
have been using a temp buffer. Drop that.

Link: https://lore.kernel.org/r/20220226230435.38733-7-michael.christie@oracle.com
Reviewed-by: Chris Leech 
Reviewed-by: Lee Duncan 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: iscsi: Stop using the SCSI pointer

2022-02-23T02:11:04+00:00

Instead of storing the iSCSI task pointer and the session age in the SCSI
pointer, use command-private variables. This patch prepares for removal of
the SCSI pointer from struct scsi_cmnd.

The list of iSCSI drivers has been obtained as follows:
$ git grep -lw iscsi_host_alloc
drivers/infiniband/ulp/iser/iscsi_iser.c
drivers/scsi/be2iscsi/be_main.c
drivers/scsi/bnx2i/bnx2i_iscsi.c
drivers/scsi/cxgbi/libcxgbi.c
drivers/scsi/iscsi_tcp.c
drivers/scsi/libiscsi.c
drivers/scsi/qedi/qedi_main.c
drivers/scsi/qla4xxx/ql4_os.c
include/scsi/libiscsi.h

Note: it is not clear to me how the qla4xxx driver can work without this
patch since it uses the scsi_cmnd::SCp.ptr member for two different
purposes:
- The qla4xxx driver uses this member to store a struct srb pointer.
- libiscsi uses this member to store a struct iscsi_task pointer.

Reviewed-by: Lee Duncan 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Himanshu Madhani 
Cc: Chris Leech 
Cc: Sagi Grimberg 
Cc: Nilesh Javali 
Cc: Manish Rangankar 
Cc: Karen Xie 
Cc: Ketan Mukadam 
Signed-off-by: Bart Van Assche 

iscsi

Link: https://lore.kernel.org/r/20220218195117.25689-26-bvanassche@acm.org
Signed-off-by: Martin K. Petersen