Merge branch 'for-4.14/block-postmerge' of git://git.kernel.dk/linux-block

Pull followup block layer updates from Jens Axboe:
 "I ended up splitting the main pull request for this series into two,
  mainly because of clashes between NVMe fixes that went into 4.13 after
  the for-4.14 branches were split off. This pull request is mostly
  NVMe, but not exclusively. In detail, it contains:

   - Two pull request for NVMe changes from Christoph. Nothing new on
     the feature front, basically just fixes all over the map for the
     core bits, transport, rdma, etc.

   - Series from Bart, cleaning up various bits in the BFQ scheduler.

   - Series of bcache fixes, which has been lingering for a release or
     two. Coly sent this in, but patches from various people in this
     area.

   - Set of patches for BFQ from Paolo himself, updating both
     documentation and fixing some corner cases in performance.

   - Series from Omar, attempting to now get the 4k loop support
     correct. Our confidence level is higher this time.

   - Series from Shaohua for loop as well, improving O_DIRECT
     performance and fixing a use-after-free"

* 'for-4.14/block-postmerge' of git://git.kernel.dk/linux-block: (74 commits)
  bcache: initialize dirty stripes in flash_dev_run()
  loop: set physical block size to logical block size
  bcache: fix bch_hprint crash and improve output
  bcache: Update continue_at() documentation
  bcache: silence static checker warning
  bcache: fix for gc and write-back race
  bcache: increase the number of open buckets
  bcache: Correct return value for sysfs attach errors
  bcache: correct cache_dirty_target in __update_writeback_rate()
  bcache: gc does not work when triggering by manual command
  bcache: Don't reinvent the wheel but use existing llist API
  bcache: do not subtract sectors_to_gc for bypassed IO
  bcache: fix sequential large write IO bypass
  bcache: Fix leak of bdev reference
  block/loop: remove unused field
  block/loop: fix use after free
  bfq: Use icq_to_bic() consistently
  bfq: Suppress compiler warnings about comparisons
  bfq: Check kstrtoul() return value
  bfq: Declare local functions static
  ...

1 files changed, 10 insertions, 38 deletions

diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
index 309c84aa7595..421e43bf1dd7 100644
--- a/drivers/nvme/target/fc.c
+++ b/drivers/nvme/target/fc.c
@@ -58,7 +58,8 @@ struct nvmet_fc_ls_iod {
 	struct work_struct		work;
 } __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 {
 	NVMET_FCP_NODATA,
@@ -74,9 +75,7 @@ struct nvmet_fc_fcp_iod {
 	struct nvme_fc_ersp_iu		rspiubuf;
 	dma_addr_t			rspdma;
 	struct scatterlist		*data_sg;
-	struct scatterlist		*next_sg;
 	int				data_sg_cnt;
-	u32				next_sg_offset;
 	u32				total_length;
 	u32				offset;
 	enum nvmet_fcp_datadir		io_dir;
@@ -112,6 +111,7 @@ struct nvmet_fc_tgtport {
 	struct ida			assoc_cnt;
 	struct nvmet_port		*port;
 	struct kref			ref;
+	u32				max_sg_cnt;
 };
 
 struct nvmet_fc_defer_fcp_req {
@@ -994,6 +994,8 @@ 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);
 
 	ret = nvmet_fc_alloc_ls_iodlist(newrec);
 	if (ret) {
@@ -1866,51 +1868,23 @@ 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, *datasg;
 	unsigned long flags;
-	u32 tlen, sg_off;
+	u32 tlen;
 	int ret;
 
 	fcpreq->op = op;
 	fcpreq->offset = fod->offset;
 	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));
-	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->transferred_length = 0;
 	fcpreq->fcp_error = 0;
 	fcpreq->rsplen = 0;
 
-	fcpreq->sg_cnt = 0;
-
-	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++;
-	}
+	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
@@ -2225,8 +2199,6 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
 	fod->req.sg = fod->data_sg;
 	fod->req.sg_cnt = fod->data_sg_cnt;
 	fod->offset = 0;
-	fod->next_sg = fod->data_sg;
-	fod->next_sg_offset = 0;
 
 	if (fod->io_dir == NVMET_FCP_WRITE) {
 		/* pull the data over before invoking nvmet layer */