linux-toradex.git/drivers/nvme/target/fc.c, branch v5.0

nvmet-fc: remove the IN_ISR deferred scheduling options

2018-12-08T05:26:57+00:00

All target lldd's call the cmd receive and op completions in non-isr
thread contexts. As such the IN_ISR options are not necessary.
Remove the functionality and flags, which also removes cpu assignments
to queues.

Signed-off-by: James Smart 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

nvmet-fc: fix kernel-doc headers

2018-10-17T06:58:30+00:00

This patch avoids that the kernel-doc tool complains about two function
headers when building with W=1.

Signed-off-by: Bart Van Assche 
Reviewed-by: James Smart 
Signed-off-by: Christoph Hellwig

nvmet_fc: support target port removal with nvmet layer

2018-10-01T21:16:10+00:00

Currently, if a targetport has been connected to via the nvmet config
(in other words, the add_port() transport routine called, and the nvmet
port pointer stored for using in upcalls on new io), and if the
targetport is then removed (say the lldd driver decides to unload or
fully reset its hardware) and then re-added (the lldd driver reloads or
reinits its hardware), the port pointer has been lost so there's no way
to continue to post commands up to nvmet via the transport port.

Correct by allocating a small "port context" structure that will be
linked to by the targetport. The context will save the targetport WWN's
and the nvmet port pointer to use for it.  Initial allocation will occur
when the targetport is bound to via add_port.  The context will be
deallocated when remove_port() is called.  If a targetport is removed
while nvmet has the active port context, the targetport will be unlinked
from the port context before removal.  If a new targetport is registered,
the port contexts without a binding are looked through and if the WWN's
match (so it's the same as nvmet's port context) the port context is
linked to the new target port.  Thus new io can be received on the new
targetport and operation resumes with nvmet.

Additionally, this also resolves nvmet configuration changing out from
underneath of the nvme-fc target port (for example: a nvmetcli clear).

Signed-off-by: James Smart 
Signed-off-by: Christoph Hellwig

nvme-fc: fix for a minor typos

2018-10-01T21:16:09+00:00

Signed-off-by: Milan P. Gandhi 
Reviewed-by: James Smart 
Signed-off-by: Christoph Hellwig

nvmet-fc: fix target sgl list on large transfers

2018-07-24T11:44:09+00:00

The existing code to carve up the sg list expected an sg element-per-page
which can be very incorrect with iommu's remapping multiple memory pages
to fewer bus addresses. To hit this error required a large io payload
(greater than 256k) and a system that maps on a per-page basis. It's
possible that large ios could get by fine if the system condensed the
sgl list into the first 64 elements.

This patch corrects the sg list handling by specifically walking the
sg list element by element and attempting to divide the transfer up
on a per-sg element boundary. While doing so, it still tries to keep
sequences under 256k, but will exceed that rule if a single sg element
is larger than 256k.

Fixes: 48fa362b6c3f ("nvmet-fc: simplify sg list handling")
Cc:  # 4.14
Signed-off-by: James Smart 
Signed-off-by: Christoph Hellwig

nvmet-fc: increase LS buffer count per fc port

2018-05-25T14:50:12+00:00

Todays limit on concurrent LS's is very small - 4 buffers. With large
subsystem counts or large numbers of initiators connecting, the limit
may be exceeded.

Raise the LS buffer count to 256.

Signed-off-by: James Smart 
Signed-off-by: Christoph Hellwig

nvmet: constify struct nvmet_fabrics_ops

2018-03-26T14:53:43+00:00

Signed-off-by: Christoph Hellwig 
Signed-off-by: Keith Busch 
Signed-off-by: Jens Axboe

nvmet_fc: prevent new io rqsts in possible isr completions

2018-03-26T14:53:43+00:00

When a bio completion calls back into the transport for a
back-end io device, the request completion path can free
the transport io job structure allowing it to be reused for
other operations. The transport has a defer_rcv queue which
holds temporary cmd rcv ops while waitng for io job structures.
when the job frees, if there's a cmd waiting, it is picked up
and submitted for processing, which can call back out to the
bio path if it's a read.  Unfortunately, what is unknown is the
context of the original bio done call, and it may be in a state
(softirq) that is not compatible with submitting the new bio in
the same calling sequence. This is especially true when using
scsi back-end devices as scsi is in softirq when it makes the
done call.

Correct by scheduling the io to be started via workq rather
than calling the start new io path inline to the original bio
done path.

Signed-off-by: James Smart 
Signed-off-by: Keith Busch 
Signed-off-by: Jens Axboe

nvmet-fc: cleanup nvmet add_port/remove_port

2018-01-08T10:01:56+00:00

The current fc transport add_port routine validates that there is a
matching port to the target port config. It then takes a reference
on the targetport. The del_port removes the reference.

Unfortunately, if the LLDD undergoes a hw reset or driver unload and
wants to unreg the targetport, due to the reference, the targetport
effectively can't be removed. It requires the admin to remove the
port from the nvmet config first, which calls the del_port.
Note: it appears nvmetcli clear skips over the del_port call (I'm
not attempting to change that).

There's no real reason to take the reference. With FC, there is nothing
to enable or disable as the presence of the FC targetport implicitly
means its enabled, and removal of the targtport means its disabled.

Change add_port to simply validate and change remove_port to a noop.
No references are taken on the targetport.

Signed-off-by: James Smart 
Signed-off-by: Christoph Hellwig

nvmet/fc: Use sgl_alloc() and sgl_free()

2018-01-06T16:18:00+00:00

Use the sgl_alloc() and sgl_free() functions instead of open coding
these functions.

Signed-off-by: Bart Van Assche 
Reviewed-by: Johannes Thumshirn 
Reviewed-by: Hannes Reinecke 
Reviewed-by:  James Smart 
Cc: Keith Busch 
Cc: Christoph Hellwig 
Cc: Sagi Grimberg 
Signed-off-by: Jens Axboe