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authorJavier González <javier@javigon.com>2018-10-09 13:12:15 +0200
committerJens Axboe <axboe@kernel.dk>2018-10-09 16:25:08 +0200
commit766c8ceb16fce904d6b8985ca2c0a547e053d1d5 (patch)
tree36e7d365c27ed8c6173375b4ba59d5b6980dbdfa /drivers/lightnvm/pblk-init.c
parentlightnvm: pblk: consider max hw sectors supported for max_write_pgs (diff)
downloadlinux-766c8ceb16fce904d6b8985ca2c0a547e053d1d5.tar.xz
linux-766c8ceb16fce904d6b8985ca2c0a547e053d1d5.zip
lightnvm: pblk: guarantee that backpointer is respected on writer stall
pblk's write buffer must guarantee that it respects the device's constrains for reads (i.e., mw_cunits). This is done by maintaining a backpointer that updates the L2P table as entries wrap up, making them point to the media instead of pointing to the write buffer. This mechanism can race in case that the write thread stalls, as the write pointer will protect the last written entry, thus disregarding the read constrains. This patch adds an extra check on wrap up, making sure that the threshold is respected at all times, preventing new entries to overwrite committed data, also in case of write thread stall. Reported-by: Heiner Litz <hlitz@ucsc.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Reviewed-by: Heiner Litz <hlitz@ucsc.edu> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/lightnvm/pblk-init.c')
-rw-r--r--drivers/lightnvm/pblk-init.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
index e5239aba806b..13822594647c 100644
--- a/drivers/lightnvm/pblk-init.c
+++ b/drivers/lightnvm/pblk-init.c
@@ -193,8 +193,9 @@ static int pblk_rwb_init(struct pblk *pblk)
struct nvm_tgt_dev *dev = pblk->dev;
struct nvm_geo *geo = &dev->geo;
unsigned long buffer_size;
- int pgs_in_buffer;
+ int pgs_in_buffer, threshold;
+ threshold = geo->mw_cunits * geo->all_luns;
pgs_in_buffer = (max(geo->mw_cunits, geo->ws_opt) + geo->ws_opt)
* geo->all_luns;
@@ -203,7 +204,7 @@ static int pblk_rwb_init(struct pblk *pblk)
else
buffer_size = pgs_in_buffer;
- return pblk_rb_init(&pblk->rwb, buffer_size, geo->csecs);
+ return pblk_rb_init(&pblk->rwb, buffer_size, threshold, geo->csecs);
}
/* Minimum pages needed within a lun */