Re: [PATCH 1/3] lightnvm: pblk: refactor metadata paths

On 29 Aug 2018, at 15.02, Matias Bjørling [off-list ref] wrote:

On 08/29/2018 10:56 AM, Javier González wrote:

quoted

pblk maintains two different metadata paths for smeta and emeta, which
store metadata at the start of the line and at the end of the line,
respectively. Until now, these path has been common for writing and
retrieving metadata, however, as these paths diverge, the common code
becomes less clear and unnecessary complicated.
In preparation for further changes to the metadata write path, this
patch separates the write and read paths for smeta and emeta and
removes the synchronous emeta path as it not used anymore (emeta is
scheduled asynchronously to prevent jittering due to internal I/Os).
Signed-off-by: Javier González <redacted>
---
 drivers/lightnvm/pblk-core.c     | 338 ++++++++++++++++++---------------------
 drivers/lightnvm/pblk-gc.c       |   2 +-
 drivers/lightnvm/pblk-recovery.c |   4 +-
 drivers/lightnvm/pblk.h          |   4 +-
 4 files changed, 163 insertions(+), 185 deletions(-)

diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
index dbf037b2b32f..09160ec02c5f 100644
--- a/drivers/lightnvm/pblk-core.c
+++ b/drivers/lightnvm/pblk-core.c

@@ -661,12 +661,137 @@ u64 pblk_lookup_page(struct pblk *pblk, struct pblk_line *line)
 	return paddr;
 }
 -/*
- * Submit emeta to one LUN in the raid line at the time to avoid a deadlock when
- * taking the per LUN semaphore.
- */
-static int pblk_line_submit_emeta_io(struct pblk *pblk, struct pblk_line *line,
-				     void *emeta_buf, u64 paddr, int dir)
+u64 pblk_line_smeta_start(struct pblk *pblk, struct pblk_line *line)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line_meta *lm = &pblk->lm;
+	int bit;
+
+	/* This usually only happens on bad lines */
+	bit = find_first_zero_bit(line->blk_bitmap, lm->blk_per_line);
+	if (bit >= lm->blk_per_line)
+		return -1;
+
+	return bit * geo->ws_opt;
+}
+
+int pblk_line_smeta_read(struct pblk *pblk, struct pblk_line *line)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct bio *bio;
+	struct nvm_rq rqd;
+	u64 paddr = pblk_line_smeta_start(pblk, line);
+	int i, ret;
+
+	memset(&rqd, 0, sizeof(struct nvm_rq));
+
+	rqd.meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
+							&rqd.dma_meta_list);
+	if (!rqd.meta_list)
+		return -ENOMEM;
+
+	rqd.ppa_list = rqd.meta_list + pblk_dma_meta_size;
+	rqd.dma_ppa_list = rqd.dma_meta_list + pblk_dma_meta_size;

If patch 2 is put first, then this is not needed.

True... I will reorder with the changes on 2/3.