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path: root/drivers/nvme/target/fc.c
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Diffstat (limited to 'drivers/nvme/target/fc.c')
-rw-r--r--drivers/nvme/target/fc.c44
1 files changed, 35 insertions, 9 deletions
diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
index 408279cb6f2c..29b4b236afd8 100644
--- a/drivers/nvme/target/fc.c
+++ b/drivers/nvme/target/fc.c
@@ -58,8 +58,8 @@ struct nvmet_fc_ls_iod {
struct work_struct work;
} __aligned(sizeof(unsigned long long));
+/* desired maximum for a single sequence - if sg list allows it */
#define NVMET_FC_MAX_SEQ_LENGTH (256 * 1024)
-#define NVMET_FC_MAX_XFR_SGENTS (NVMET_FC_MAX_SEQ_LENGTH / PAGE_SIZE)
enum nvmet_fcp_datadir {
NVMET_FCP_NODATA,
@@ -74,6 +74,7 @@ struct nvmet_fc_fcp_iod {
struct nvme_fc_cmd_iu cmdiubuf;
struct nvme_fc_ersp_iu rspiubuf;
dma_addr_t rspdma;
+ struct scatterlist *next_sg;
struct scatterlist *data_sg;
int data_sg_cnt;
u32 offset;
@@ -1025,8 +1026,7 @@ nvmet_fc_register_targetport(struct nvmet_fc_port_info *pinfo,
INIT_LIST_HEAD(&newrec->assoc_list);
kref_init(&newrec->ref);
ida_init(&newrec->assoc_cnt);
- newrec->max_sg_cnt = min_t(u32, NVMET_FC_MAX_XFR_SGENTS,
- template->max_sgl_segments);
+ newrec->max_sg_cnt = template->max_sgl_segments;
ret = nvmet_fc_alloc_ls_iodlist(newrec);
if (ret) {
@@ -1722,6 +1722,7 @@ nvmet_fc_alloc_tgt_pgs(struct nvmet_fc_fcp_iod *fod)
((fod->io_dir == NVMET_FCP_WRITE) ?
DMA_FROM_DEVICE : DMA_TO_DEVICE));
/* note: write from initiator perspective */
+ fod->next_sg = fod->data_sg;
return 0;
@@ -1866,24 +1867,49 @@ nvmet_fc_transfer_fcp_data(struct nvmet_fc_tgtport *tgtport,
struct nvmet_fc_fcp_iod *fod, u8 op)
{
struct nvmefc_tgt_fcp_req *fcpreq = fod->fcpreq;
+ struct scatterlist *sg = fod->next_sg;
unsigned long flags;
- u32 tlen;
+ u32 remaininglen = fod->req.transfer_len - fod->offset;
+ u32 tlen = 0;
int ret;
fcpreq->op = op;
fcpreq->offset = fod->offset;
fcpreq->timeout = NVME_FC_TGTOP_TIMEOUT_SEC;
- tlen = min_t(u32, tgtport->max_sg_cnt * PAGE_SIZE,
- (fod->req.transfer_len - fod->offset));
+ /*
+ * for next sequence:
+ * break at a sg element boundary
+ * attempt to keep sequence length capped at
+ * NVMET_FC_MAX_SEQ_LENGTH but allow sequence to
+ * be longer if a single sg element is larger
+ * than that amount. This is done to avoid creating
+ * a new sg list to use for the tgtport api.
+ */
+ fcpreq->sg = sg;
+ fcpreq->sg_cnt = 0;
+ while (tlen < remaininglen &&
+ fcpreq->sg_cnt < tgtport->max_sg_cnt &&
+ tlen + sg_dma_len(sg) < NVMET_FC_MAX_SEQ_LENGTH) {
+ fcpreq->sg_cnt++;
+ tlen += sg_dma_len(sg);
+ sg = sg_next(sg);
+ }
+ if (tlen < remaininglen && fcpreq->sg_cnt == 0) {
+ fcpreq->sg_cnt++;
+ tlen += min_t(u32, sg_dma_len(sg), remaininglen);
+ sg = sg_next(sg);
+ }
+ if (tlen < remaininglen)
+ fod->next_sg = sg;
+ else
+ fod->next_sg = NULL;
+
fcpreq->transfer_length = tlen;
fcpreq->transferred_length = 0;
fcpreq->fcp_error = 0;
fcpreq->rsplen = 0;
- fcpreq->sg = &fod->data_sg[fod->offset / PAGE_SIZE];
- fcpreq->sg_cnt = DIV_ROUND_UP(tlen, PAGE_SIZE);
-
/*
* If the last READDATA request: check if LLDD supports
* combined xfr with response.