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authorBart Van Assche <bvanassche@acm.org>2010-11-26 14:50:09 -0500
committerDavid Dillow <dillowda@ornl.gov>2011-01-10 15:44:50 -0500
commit94a9174c630c8465ed9e97ecd242993429930c05 (patch)
tree73ddbe0024d54bad543c90144576148b70922eea /drivers/infiniband
parent76c75b258f1fe6abac6af2356989ad4d6518886e (diff)
downloadop-kernel-dev-94a9174c630c8465ed9e97ecd242993429930c05.zip
op-kernel-dev-94a9174c630c8465ed9e97ecd242993429930c05.tar.gz
IB/srp: reduce lock coverage of command completion
We only need the lock to cover list and credit manipulations, so push those into srp_remove_req() and update the call chains. We reorder the request removal and command completion in srp_process_rsp() to avoid the SCSI mid-layer sending another command before we've released our request and added any credits returned by the target. This prevents us from returning HOST_BUSY unneccesarily. Signed-off-by: Bart Van Assche <bvanassche@acm.org> [ broken out, small cleanups, and modified to avoid potential extraneous HOST_BUSY returns by David Dillow ] Signed-off-by: David Dillow <dillowda@ornl.gov>
Diffstat (limited to 'drivers/infiniband')
-rw-r--r--drivers/infiniband/ulp/srp/ib_srp.c37
1 files changed, 14 insertions, 23 deletions
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index e5bd181..e76fe54 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -549,18 +549,24 @@ static void srp_unmap_data(struct scsi_cmnd *scmnd,
scsi_sg_count(scmnd), scmnd->sc_data_direction);
}
-static void srp_remove_req(struct srp_target_port *target, struct srp_request *req)
+static void srp_remove_req(struct srp_target_port *target,
+ struct srp_request *req, s32 req_lim_delta)
{
+ unsigned long flags;
+
srp_unmap_data(req->scmnd, target, req);
+ spin_lock_irqsave(target->scsi_host->host_lock, flags);
+ target->req_lim += req_lim_delta;
req->scmnd = NULL;
list_add_tail(&req->list, &target->free_reqs);
+ spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
}
static void srp_reset_req(struct srp_target_port *target, struct srp_request *req)
{
req->scmnd->result = DID_RESET << 16;
req->scmnd->scsi_done(req->scmnd);
- srp_remove_req(target, req);
+ srp_remove_req(target, req, 0);
}
static int srp_reconnect_target(struct srp_target_port *target)
@@ -595,13 +601,11 @@ static int srp_reconnect_target(struct srp_target_port *target)
while (ib_poll_cq(target->send_cq, 1, &wc) > 0)
; /* nothing */
- spin_lock_irq(target->scsi_host->host_lock);
for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
struct srp_request *req = &target->req_ring[i];
if (req->scmnd)
srp_reset_req(target, req);
}
- spin_unlock_irq(target->scsi_host->host_lock);
INIT_LIST_HEAD(&target->free_tx);
for (i = 0; i < SRP_SQ_SIZE; ++i)
@@ -914,15 +918,12 @@ static void srp_process_rsp(struct srp_target_port *target, struct srp_rsp *rsp)
struct srp_request *req;
struct scsi_cmnd *scmnd;
unsigned long flags;
- s32 delta;
-
- delta = (s32) be32_to_cpu(rsp->req_lim_delta);
-
- spin_lock_irqsave(target->scsi_host->host_lock, flags);
-
- target->req_lim += delta;
if (unlikely(rsp->tag & SRP_TAG_TSK_MGMT)) {
+ spin_lock_irqsave(target->scsi_host->host_lock, flags);
+ target->req_lim += be32_to_cpu(rsp->req_lim_delta);
+ spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
+
target->tsk_mgmt_status = -1;
if (be32_to_cpu(rsp->resp_data_len) >= 4)
target->tsk_mgmt_status = rsp->data[3];
@@ -948,12 +949,10 @@ static void srp_process_rsp(struct srp_target_port *target, struct srp_rsp *rsp)
else if (rsp->flags & (SRP_RSP_FLAG_DIOVER | SRP_RSP_FLAG_DIUNDER))
scsi_set_resid(scmnd, be32_to_cpu(rsp->data_in_res_cnt));
+ srp_remove_req(target, req, be32_to_cpu(rsp->req_lim_delta));
scmnd->host_scribble = NULL;
scmnd->scsi_done(scmnd);
- srp_remove_req(target, req);
}
-
- spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
}
static int srp_response_common(struct srp_target_port *target, s32 req_delta,
@@ -1498,18 +1497,14 @@ static int srp_abort(struct scsi_cmnd *scmnd)
SRP_TSK_ABORT_TASK))
return FAILED;
- spin_lock_irq(target->scsi_host->host_lock);
-
if (req->scmnd) {
if (!target->tsk_mgmt_status) {
- srp_remove_req(target, req);
+ srp_remove_req(target, req, 0);
scmnd->result = DID_ABORT << 16;
} else
ret = FAILED;
}
- spin_unlock_irq(target->scsi_host->host_lock);
-
return ret;
}
@@ -1528,16 +1523,12 @@ static int srp_reset_device(struct scsi_cmnd *scmnd)
if (target->tsk_mgmt_status)
return FAILED;
- spin_lock_irq(target->scsi_host->host_lock);
-
for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
struct srp_request *req = &target->req_ring[i];
if (req->scmnd && req->scmnd->device == scmnd->device)
srp_reset_req(target, req);
}
- spin_unlock_irq(target->scsi_host->host_lock);
-
return SUCCESS;
}
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