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ibmvscsis: Fix the incorrect req_lim_delta

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The current code is not correctly calculating the req_lim_delta.

We want to make sure vscsi->credit is always incremented when
we do not send a response for the scsi op. Thus for the case where
there is a successfully aborted task we need to make sure the
vscsi->credit is incremented.

v2 - Moves the original location of the vscsi->credit increment
to a better spot. Since if we increment credit, the next command
we send back will have increased req_lim_delta. But we probably
shouldn't be doing that until the aborted cmd is actually released.
Otherwise the client will think that it can send a new command, and
we could find ourselves short of command elements. Not likely, but could
happen.

This patch depends on both:
commit 25e7853126 ("ibmvscsis: Do not send aborted task response")
commit 98883f1b54 ("ibmvscsis: Clear left-over abort_cmd pointers")

Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Reviewed-by: Michael Cyr <mikecyr@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org> # v4.8+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Bryant G. Ly 2017-05-10 14:35:47 -05:00 committed by Nicholas Bellinger
parent 98883f1b54
commit 75dbf2d36f
1 changed files with 20 additions and 4 deletions
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24
drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
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@ -1791,6 +1791,25 @@ static void ibmvscsis_send_messages(struct scsi_info *vscsi)
list_del(&cmd->list);
ibmvscsis_free_cmd_resources(vscsi,
cmd);
/*
* With a successfully aborted op
* through LIO we want to increment the
* the vscsi credit so that when we dont
* send a rsp to the original scsi abort
* op (h_send_crq), but the tm rsp to
* the abort is sent, the credit is
* correctly sent with the abort tm rsp.
* We would need 1 for the abort tm rsp
* and 1 credit for the aborted scsi op.
* Thus we need to increment here.
* Also we want to increment the credit
* here because we want to make sure
* cmd is actually released first
* otherwise the client will think it
* it can send a new cmd, and we could
* find ourselves short of cmd elements.
*/
vscsi->credit += 1;
} else {
iue = cmd->iue;
@ -2965,10 +2984,7 @@ static long srp_build_response(struct scsi_info *vscsi,
rsp->opcode = SRP_RSP;
if (vscsi->credit > 0 && vscsi->state == SRP_PROCESSING)
rsp->req_lim_delta = cpu_to_be32(vscsi->credit);
else
rsp->req_lim_delta = cpu_to_be32(1 + vscsi->credit);
rsp->req_lim_delta = cpu_to_be32(1 + vscsi->credit);
rsp->tag = cmd->rsp.tag;
rsp->flags = 0;