| Message ID | 1494444947-77322-1-git-send-email-bryantly@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Wed, 2017-05-10 at 14:35 -0500, Bryant G. Ly wrote: > 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 25e78531268e ("ibmvscsis: Do not send aborted task response") > commit 38b2788edbd6 ("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+ > --- > drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c | 24 ++++++++++++++++++++---- > 1 file changed, 20 insertions(+), 4 deletions(-) > > diff --git a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c > index ee64241..abf6026 100644 > --- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c > +++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c > @@ -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; > Thanks Bryant. Will apply post -rc1.
diff --git a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c index ee64241..abf6026 100644 --- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c +++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c @@ -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;
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 25e78531268e ("ibmvscsis: Do not send aborted task response") commit 38b2788edbd6 ("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+ --- drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-)