Commit 48fa362b authored by James Smart's avatar James Smart Committed by Sagi Grimberg

nvmet-fc: simplify sg list handling

The existing nvmet_fc sg list handling has 2 faults:
a) the request between LLDD and transport has too large of an sg
   list (256 elements), which is normally 256k (64 elements).
b) sglist handling doesn't optimize on the fact that each element
   is a page.

This patch removes the static sg list in the request and uses the
dynamic list already present in the nvmet_fc transport. It also
simplies the handling of the sg list on multiple sequences to
take advantage of the per-page divisions.
Signed-off-by: default avatarJames Smart <james.smart@broadcom.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 5533d424
...@@ -58,7 +58,8 @@ struct nvmet_fc_ls_iod { ...@@ -58,7 +58,8 @@ struct nvmet_fc_ls_iod {
struct work_struct work; struct work_struct work;
} __aligned(sizeof(unsigned long long)); } __aligned(sizeof(unsigned long long));
#define NVMET_FC_MAX_KB_PER_XFR 256 #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 { enum nvmet_fcp_datadir {
NVMET_FCP_NODATA, NVMET_FCP_NODATA,
...@@ -74,9 +75,7 @@ struct nvmet_fc_fcp_iod { ...@@ -74,9 +75,7 @@ struct nvmet_fc_fcp_iod {
struct nvme_fc_ersp_iu rspiubuf; struct nvme_fc_ersp_iu rspiubuf;
dma_addr_t rspdma; dma_addr_t rspdma;
struct scatterlist *data_sg; struct scatterlist *data_sg;
struct scatterlist *next_sg;
int data_sg_cnt; int data_sg_cnt;
u32 next_sg_offset;
u32 total_length; u32 total_length;
u32 offset; u32 offset;
enum nvmet_fcp_datadir io_dir; enum nvmet_fcp_datadir io_dir;
...@@ -112,6 +111,7 @@ struct nvmet_fc_tgtport { ...@@ -112,6 +111,7 @@ struct nvmet_fc_tgtport {
struct ida assoc_cnt; struct ida assoc_cnt;
struct nvmet_port *port; struct nvmet_port *port;
struct kref ref; struct kref ref;
u32 max_sg_cnt;
}; };
struct nvmet_fc_defer_fcp_req { struct nvmet_fc_defer_fcp_req {
...@@ -994,6 +994,8 @@ nvmet_fc_register_targetport(struct nvmet_fc_port_info *pinfo, ...@@ -994,6 +994,8 @@ nvmet_fc_register_targetport(struct nvmet_fc_port_info *pinfo,
INIT_LIST_HEAD(&newrec->assoc_list); INIT_LIST_HEAD(&newrec->assoc_list);
kref_init(&newrec->ref); kref_init(&newrec->ref);
ida_init(&newrec->assoc_cnt); ida_init(&newrec->assoc_cnt);
newrec->max_sg_cnt = min_t(u32, NVMET_FC_MAX_XFR_SGENTS,
template->max_sgl_segments);
ret = nvmet_fc_alloc_ls_iodlist(newrec); ret = nvmet_fc_alloc_ls_iodlist(newrec);
if (ret) { if (ret) {
...@@ -1866,51 +1868,23 @@ nvmet_fc_transfer_fcp_data(struct nvmet_fc_tgtport *tgtport, ...@@ -1866,51 +1868,23 @@ nvmet_fc_transfer_fcp_data(struct nvmet_fc_tgtport *tgtport,
struct nvmet_fc_fcp_iod *fod, u8 op) struct nvmet_fc_fcp_iod *fod, u8 op)
{ {
struct nvmefc_tgt_fcp_req *fcpreq = fod->fcpreq; struct nvmefc_tgt_fcp_req *fcpreq = fod->fcpreq;
struct scatterlist *sg, *datasg;
unsigned long flags; unsigned long flags;
u32 tlen, sg_off; u32 tlen;
int ret; int ret;
fcpreq->op = op; fcpreq->op = op;
fcpreq->offset = fod->offset; fcpreq->offset = fod->offset;
fcpreq->timeout = NVME_FC_TGTOP_TIMEOUT_SEC; fcpreq->timeout = NVME_FC_TGTOP_TIMEOUT_SEC;
tlen = min_t(u32, (NVMET_FC_MAX_KB_PER_XFR * 1024),
tlen = min_t(u32, tgtport->max_sg_cnt * PAGE_SIZE,
(fod->total_length - fod->offset)); (fod->total_length - fod->offset));
tlen = min_t(u32, tlen, NVME_FC_MAX_SEGMENTS * PAGE_SIZE);
tlen = min_t(u32, tlen, fod->tgtport->ops->max_sgl_segments
* PAGE_SIZE);
fcpreq->transfer_length = tlen; fcpreq->transfer_length = tlen;
fcpreq->transferred_length = 0; fcpreq->transferred_length = 0;
fcpreq->fcp_error = 0; fcpreq->fcp_error = 0;
fcpreq->rsplen = 0; fcpreq->rsplen = 0;
fcpreq->sg_cnt = 0; fcpreq->sg = &fod->data_sg[fod->offset / PAGE_SIZE];
fcpreq->sg_cnt = DIV_ROUND_UP(tlen, PAGE_SIZE);
datasg = fod->next_sg;
sg_off = fod->next_sg_offset;
for (sg = fcpreq->sg ; tlen; sg++) {
*sg = *datasg;
if (sg_off) {
sg->offset += sg_off;
sg->length -= sg_off;
sg->dma_address += sg_off;
sg_off = 0;
}
if (tlen < sg->length) {
sg->length = tlen;
fod->next_sg = datasg;
fod->next_sg_offset += tlen;
} else if (tlen == sg->length) {
fod->next_sg_offset = 0;
fod->next_sg = sg_next(datasg);
} else {
fod->next_sg_offset = 0;
datasg = sg_next(datasg);
}
tlen -= sg->length;
fcpreq->sg_cnt++;
}
/* /*
* If the last READDATA request: check if LLDD supports * If the last READDATA request: check if LLDD supports
...@@ -2225,8 +2199,6 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport, ...@@ -2225,8 +2199,6 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
fod->req.sg = fod->data_sg; fod->req.sg = fod->data_sg;
fod->req.sg_cnt = fod->data_sg_cnt; fod->req.sg_cnt = fod->data_sg_cnt;
fod->offset = 0; fod->offset = 0;
fod->next_sg = fod->data_sg;
fod->next_sg_offset = 0;
if (fod->io_dir == NVMET_FCP_WRITE) { if (fod->io_dir == NVMET_FCP_WRITE) {
/* pull the data over before invoking nvmet layer */ /* pull the data over before invoking nvmet layer */
......
...@@ -624,7 +624,7 @@ struct nvmefc_tgt_fcp_req { ...@@ -624,7 +624,7 @@ struct nvmefc_tgt_fcp_req {
u32 timeout; u32 timeout;
u32 transfer_length; u32 transfer_length;
struct fc_ba_rjt ba_rjt; struct fc_ba_rjt ba_rjt;
struct scatterlist sg[NVME_FC_MAX_SEGMENTS]; struct scatterlist *sg;
int sg_cnt; int sg_cnt;
void *rspaddr; void *rspaddr;
dma_addr_t rspdma; dma_addr_t rspdma;
......
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