Sorry that my Linux email client has configuration issue and can't reply email. 
Used my outlook to reply as plain text and hope that I won't corrupt the format.
Tested on my board and it works well. Since this is a good fix, I think you 
don't need to do it based on my previous v3 patch and can directly apply yours:)

Tested-by: Zhoujie Wu <z...@marvell.com>


-----Original Message-----
From: h...@owltronix.com <h...@owltronix.com> 
Sent: Tuesday, January 29, 2019 12:48 AM
To: Matias Bjorling <m...@lightnvm.io>
Cc: jav...@javigon.com; Zhoujie Wu <z...@marvell.com>; 
linux-bl...@vger.kernel.org; linux-kernel@vger.kernel.org; Hans Holmberg 
<hans.holmb...@cnexlabs.com>
Subject: [EXT] [PATCH] lightnvm: pblk: extend line wp balance check

External Email

----------------------------------------------------------------------
From: Hans Holmberg <hans.holmb...@cnexlabs.com>

pblk stripes writes of minimal write size across all non-offline chunks in a 
line, which means that the maximum write pointer delta should not exceed the 
minimal write size. Extend the line write pointer balance check to cover this 
case.

Signed-off-by: Hans Holmberg <hans.holmb...@cnexlabs.com>
---

This patch applies on top of Zhoujie's V3 of
"lightnvm: pblk: ignore bad block wp for pblk_line_wp_is_unbalanced

 drivers/lightnvm/pblk-recovery.c | 60 ++++++++++++++++++++------------
 1 file changed, 37 insertions(+), 23 deletions(-)

diff --git a/drivers/lightnvm/pblk-recovery.c b/drivers/lightnvm/pblk-recovery.c
index 02d466e6925e..d86f580036d3 100644
--- a/drivers/lightnvm/pblk-recovery.c
+++ b/drivers/lightnvm/pblk-recovery.c
@@ -302,41 +302,55 @@ static int pblk_pad_distance(struct pblk *pblk, struct 
pblk_line *line)
        return (distance > line->left_msecs) ? line->left_msecs : distance;  }
 
-static int pblk_line_wp_is_unbalanced(struct pblk *pblk,
-                                     struct pblk_line *line)
+/* Return a chunk belonging to a line by stripe(write order) index */ 
+static struct nvm_chk_meta *pblk_get_stripe_chunk(struct pblk *pblk,
+                                                 struct pblk_line *line,
+                                                 int index)
 {
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
-       struct pblk_line_meta *lm = &pblk->lm;
        struct pblk_lun *rlun;
-       struct nvm_chk_meta *chunk;
        struct ppa_addr ppa;
-       u64 line_wp;
-       int pos, i, bit;
+       int pos;
 
-       bit = find_first_zero_bit(line->blk_bitmap, lm->blk_per_line);
-       if (bit >= lm->blk_per_line)
-               return 0;
-       rlun = &pblk->luns[bit];
+       rlun = &pblk->luns[index];
        ppa = rlun->bppa;
        pos = pblk_ppa_to_pos(geo, ppa);
-       chunk = &line->chks[pos];
 
-       line_wp = chunk->wp;
+       return &line->chks[pos];
+}
 
-       for (i = bit + 1; i < lm->blk_per_line; i++) {
-               rlun = &pblk->luns[i];
-               ppa = rlun->bppa;
-               pos = pblk_ppa_to_pos(geo, ppa);
-               chunk = &line->chks[pos];
+static int pblk_line_wps_are_unbalanced(struct pblk *pblk,
+                                     struct pblk_line *line)
+{
+       struct pblk_line_meta *lm = &pblk->lm;
+       int blk_in_line = lm->blk_per_line;
+       struct nvm_chk_meta *chunk;
+       u64 max_wp, min_wp;
+       int i;
 
-               if (chunk->state & NVM_CHK_ST_OFFLINE)
-                       continue;
+       i = find_first_zero_bit(line->blk_bitmap, blk_in_line);
+
+       /* If there is one or zero good chunks in the line,
+        * the write pointers can't be unbalanced.
+        */
+       if (i >= (blk_in_line - 1))
+               return 0;
 
-               if (chunk->wp > line_wp)
+       chunk = pblk_get_stripe_chunk(pblk, line, i);
+       max_wp = chunk->wp;
+       if (max_wp > pblk->max_write_pgs)
+               min_wp = max_wp - pblk->max_write_pgs;
+       else
+               min_wp = 0;
+
+       i = find_next_zero_bit(line->blk_bitmap, blk_in_line, i + 1);
+       while (i < blk_in_line) {
+               chunk = pblk_get_stripe_chunk(pblk, line, i);
+               if (chunk->wp > max_wp || chunk->wp < min_wp)
                        return 1;
-               else if (chunk->wp < line_wp)
-                       line_wp = chunk->wp;
+
+               i = find_next_zero_bit(line->blk_bitmap, blk_in_line, i + 1);
        }
 
        return 0;
@@ -362,7 +376,7 @@ static int pblk_recov_scan_oob(struct pblk *pblk, struct 
pblk_line *line,
        int ret;
        u64 left_ppas = pblk_sec_in_open_line(pblk, line) - lm->smeta_sec;
 
-       if (pblk_line_wp_is_unbalanced(pblk, line))
+       if (pblk_line_wps_are_unbalanced(pblk, line))
                pblk_warn(pblk, "recovering unbalanced line (%d)\n", line->id);
 
        ppa_list = p.ppa_list;
--
2.17.1

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