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authorJames Smart <jsmart2021@gmail.com>2017-04-11 11:32:28 -0700
committerChristoph Hellwig <hch@lst.de>2017-04-21 16:41:48 +0200
commit39498faef7c02f9f6de4060ccdc7e8975a6e690b (patch)
tree7b464f57fa4b1314c3f874f246864b8a9ce6ab4d
parent1c05cf9058027dd80630d54aa3527eb2e3152e80 (diff)
downloadlinux-39498faef7c02f9f6de4060ccdc7e8975a6e690b.tar.bz2
nvmet_fc: add target feature flags for upcall isr contexts
Two new feature flags were added to control whether upcalls to the transport result in context switches or stay in the calling context. NVMET_FCTGTFEAT_CMD_IN_ISR: By default, if the flag is not set, the transport assumes the lldd is in a non-isr context and in the cpu context it should be for the io queue. As such, the cmd handler is called directly in the calling context. If the flag is set, indicating the upcall is an isr context, the transport mandates a transition to a workqueue. The workqueue assigned to the queue is used for the context. NVMET_FCTGTFEAT_OPDONE_IN_ISR By default, if the flag is not set, the transport assumes the lldd is in a non-isr context and in the cpu context it should be for the io queue. As such, the fcp operation done callback is called directly in the calling context. If the flag is set, indicating the upcall is an isr context, the transport mandates a transition to a workqueue. The workqueue assigned to the queue is used for the context. Updated lpfc for flags Signed-off-by: James Smart <james.smart@broadcom.com> Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
-rw-r--r--drivers/nvme/target/fc.c37
-rw-r--r--drivers/nvme/target/fcloop.c5
-rw-r--r--drivers/scsi/lpfc/lpfc_nvmet.c4
-rw-r--r--include/linux/nvme-fc-driver.h16
4 files changed, 56 insertions, 6 deletions
diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
index 2c0709f0a7d3..a4fad3d0b660 100644
--- a/drivers/nvme/target/fc.c
+++ b/drivers/nvme/target/fc.c
@@ -86,6 +86,7 @@ struct nvmet_fc_fcp_iod {
struct nvmet_req req;
struct work_struct work;
+ struct work_struct done_work;
struct nvmet_fc_tgtport *tgtport;
struct nvmet_fc_tgt_queue *queue;
@@ -213,6 +214,7 @@ static DEFINE_IDA(nvmet_fc_tgtport_cnt);
static void nvmet_fc_handle_ls_rqst_work(struct work_struct *work);
static void nvmet_fc_handle_fcp_rqst_work(struct work_struct *work);
+static void nvmet_fc_fcp_rqst_op_done_work(struct work_struct *work);
static void nvmet_fc_tgt_a_put(struct nvmet_fc_tgt_assoc *assoc);
static int nvmet_fc_tgt_a_get(struct nvmet_fc_tgt_assoc *assoc);
static void nvmet_fc_tgt_q_put(struct nvmet_fc_tgt_queue *queue);
@@ -414,6 +416,7 @@ nvmet_fc_prep_fcp_iodlist(struct nvmet_fc_tgtport *tgtport,
for (i = 0; i < queue->sqsize; fod++, i++) {
INIT_WORK(&fod->work, nvmet_fc_handle_fcp_rqst_work);
+ INIT_WORK(&fod->done_work, nvmet_fc_fcp_rqst_op_done_work);
fod->tgtport = tgtport;
fod->queue = queue;
fod->active = false;
@@ -1807,10 +1810,13 @@ nvmet_fc_transfer_fcp_data(struct nvmet_fc_tgtport *tgtport,
}
}
+/*
+ * actual done handler for FCP operations when completed by the lldd
+ */
static void
-nvmet_fc_xmt_fcp_op_done(struct nvmefc_tgt_fcp_req *fcpreq)
+nvmet_fc_fod_op_done(struct nvmet_fc_fcp_iod *fod)
{
- struct nvmet_fc_fcp_iod *fod = fcpreq->nvmet_fc_private;
+ struct nvmefc_tgt_fcp_req *fcpreq = fod->fcpreq;
struct nvmet_fc_tgtport *tgtport = fod->tgtport;
unsigned long flags;
bool abort;
@@ -1905,6 +1911,28 @@ nvmet_fc_xmt_fcp_op_done(struct nvmefc_tgt_fcp_req *fcpreq)
}
}
+static void
+nvmet_fc_fcp_rqst_op_done_work(struct work_struct *work)
+{
+ struct nvmet_fc_fcp_iod *fod =
+ container_of(work, struct nvmet_fc_fcp_iod, done_work);
+
+ nvmet_fc_fod_op_done(fod);
+}
+
+static void
+nvmet_fc_xmt_fcp_op_done(struct nvmefc_tgt_fcp_req *fcpreq)
+{
+ struct nvmet_fc_fcp_iod *fod = fcpreq->nvmet_fc_private;
+ struct nvmet_fc_tgt_queue *queue = fod->queue;
+
+ if (fod->tgtport->ops->target_features & NVMET_FCTGTFEAT_OPDONE_IN_ISR)
+ /* context switch so completion is not in ISR context */
+ queue_work_on(queue->cpu, queue->work_q, &fod->done_work);
+ else
+ nvmet_fc_fod_op_done(fod);
+}
+
/*
* actual completion handler after execution by the nvmet layer
*/
@@ -2149,7 +2177,10 @@ nvmet_fc_rcv_fcp_req(struct nvmet_fc_target_port *target_port,
((queue->qid - 1) % tgtport->ops->max_hw_queues) : 0;
memcpy(&fod->cmdiubuf, cmdiubuf, cmdiubuf_len);
- queue_work_on(queue->cpu, queue->work_q, &fod->work);
+ if (tgtport->ops->target_features & NVMET_FCTGTFEAT_CMD_IN_ISR)
+ queue_work_on(queue->cpu, queue->work_q, &fod->work);
+ else
+ nvmet_fc_handle_fcp_rqst(tgtport, fod);
return 0;
}
diff --git a/drivers/nvme/target/fcloop.c b/drivers/nvme/target/fcloop.c
index 4e8e6a22bce1..a5cdeca39013 100644
--- a/drivers/nvme/target/fcloop.c
+++ b/drivers/nvme/target/fcloop.c
@@ -575,8 +575,9 @@ struct nvmet_fc_target_template tgttemplate = {
.max_dif_sgl_segments = FCLOOP_SGL_SEGS,
.dma_boundary = FCLOOP_DMABOUND_4G,
/* optional features */
- .target_features = NVMET_FCTGTFEAT_READDATA_RSP |
- NVMET_FCTGTFEAT_NEEDS_CMD_CPUSCHED,
+ .target_features = NVMET_FCTGTFEAT_CMD_IN_ISR |
+ NVMET_FCTGTFEAT_NEEDS_CMD_CPUSCHED |
+ NVMET_FCTGTFEAT_OPDONE_IN_ISR,
/* sizes of additional private data for data structures */
.target_priv_sz = sizeof(struct fcloop_tport),
};
diff --git a/drivers/scsi/lpfc/lpfc_nvmet.c b/drivers/scsi/lpfc/lpfc_nvmet.c
index 7ca868f394da..176b4e035bcf 100644
--- a/drivers/scsi/lpfc/lpfc_nvmet.c
+++ b/drivers/scsi/lpfc/lpfc_nvmet.c
@@ -669,7 +669,9 @@ lpfc_nvmet_create_targetport(struct lpfc_hba *phba)
lpfc_tgttemplate.max_hw_queues = phba->cfg_nvme_io_channel;
lpfc_tgttemplate.max_sgl_segments = phba->cfg_sg_seg_cnt;
lpfc_tgttemplate.target_features = NVMET_FCTGTFEAT_READDATA_RSP |
- NVMET_FCTGTFEAT_NEEDS_CMD_CPUSCHED;
+ NVMET_FCTGTFEAT_NEEDS_CMD_CPUSCHED |
+ NVMET_FCTGTFEAT_CMD_IN_ISR |
+ NVMET_FCTGTFEAT_OPDONE_IN_ISR;
#if (IS_ENABLED(CONFIG_NVME_TARGET_FC))
error = nvmet_fc_register_targetport(&pinfo, &lpfc_tgttemplate,
diff --git a/include/linux/nvme-fc-driver.h b/include/linux/nvme-fc-driver.h
index 16eb264980c2..d70a9c98bc23 100644
--- a/include/linux/nvme-fc-driver.h
+++ b/include/linux/nvme-fc-driver.h
@@ -655,6 +655,22 @@ enum {
* on. The transport should pick a cpu to schedule the work
* on.
*/
+ NVMET_FCTGTFEAT_CMD_IN_ISR = (1 << 2),
+ /* Bit 2: When 0, the LLDD is calling the cmd rcv handler
+ * in a non-isr context, allowing the transport to finish
+ * op completion in the calling context. When 1, the LLDD
+ * is calling the cmd rcv handler in an ISR context,
+ * requiring the transport to transition to a workqueue
+ * for op completion.
+ */
+ NVMET_FCTGTFEAT_OPDONE_IN_ISR = (1 << 3),
+ /* Bit 3: When 0, the LLDD is calling the op done handler
+ * in a non-isr context, allowing the transport to finish
+ * op completion in the calling context. When 1, the LLDD
+ * is calling the op done handler in an ISR context,
+ * requiring the transport to transition to a workqueue
+ * for op completion.
+ */
};