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Message-Id: <1537257785-31630-3-git-send-email-javier@cnexlabs.com>
Date: Tue, 18 Sep 2018 10:03:03 +0200
From: "Javier González" <javier@...igon.com>
To: mb@...htnvm.io
Cc: linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
Javier González <javier@...xlabs.com>
Subject: [PATCH 2/4] lightnvm: pblk: encapsulate rb pointer operations
pblk's read/write buffer is always a power-of-2, thus wrapping up the
buffer can be done with a bit mask. Since this is an implementation
detail internal to the write buffer, make a helper that hides pointer
increment + wrap, and allows to transparently relax this assumption in
the future.
Signed-off-by: Javier González <javier@...xlabs.com>
---
drivers/lightnvm/pblk-rb.c | 21 +++++++++++++--------
drivers/lightnvm/pblk-write.c | 7 ++-----
drivers/lightnvm/pblk.h | 2 ++
3 files changed, 17 insertions(+), 13 deletions(-)
diff --git a/drivers/lightnvm/pblk-rb.c b/drivers/lightnvm/pblk-rb.c
index 82829e8151db..e46d8cb9d28b 100644
--- a/drivers/lightnvm/pblk-rb.c
+++ b/drivers/lightnvm/pblk-rb.c
@@ -169,6 +169,12 @@ static unsigned int pblk_rb_space(struct pblk_rb *rb)
return pblk_rb_ring_space(rb, mem, sync, rb->nr_entries);
}
+unsigned int pblk_rb_ptr_wrap(struct pblk_rb *rb, unsigned int p,
+ unsigned int nr_entries)
+{
+ return (p + nr_entries) & (rb->nr_entries - 1);
+}
+
/*
* Buffer count is calculated with respect to the submission entry signaling the
* entries that are available to send to the media
@@ -195,8 +201,7 @@ unsigned int pblk_rb_read_commit(struct pblk_rb *rb, unsigned int nr_entries)
subm = READ_ONCE(rb->subm);
/* Commit read means updating submission pointer */
- smp_store_release(&rb->subm,
- (subm + nr_entries) & (rb->nr_entries - 1));
+ smp_store_release(&rb->subm, pblk_rb_ptr_wrap(rb, subm, nr_entries));
return subm;
}
@@ -229,7 +234,7 @@ static int __pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int to_update)
line = pblk_ppa_to_line(pblk, w_ctx->ppa);
kref_put(&line->ref, pblk_line_put);
clean_wctx(w_ctx);
- rb->l2p_update = (rb->l2p_update + 1) & (rb->nr_entries - 1);
+ rb->l2p_update = pblk_rb_ptr_wrap(rb, rb->l2p_update, 1);
}
pblk_rl_out(&pblk->rl, user_io, gc_io);
@@ -408,7 +413,7 @@ static int pblk_rb_may_write(struct pblk_rb *rb, unsigned int nr_entries,
return 0;
/* Protect from read count */
- smp_store_release(&rb->mem, (*pos + nr_entries) & (rb->nr_entries - 1));
+ smp_store_release(&rb->mem, pblk_rb_ptr_wrap(rb, *pos, nr_entries));
return 1;
}
@@ -432,7 +437,7 @@ static int pblk_rb_may_write_flush(struct pblk_rb *rb, unsigned int nr_entries,
if (!__pblk_rb_may_write(rb, nr_entries, pos))
return 0;
- mem = (*pos + nr_entries) & (rb->nr_entries - 1);
+ mem = pblk_rb_ptr_wrap(rb, *pos, nr_entries);
*io_ret = NVM_IO_DONE;
if (bio->bi_opf & REQ_PREFLUSH) {
@@ -572,7 +577,7 @@ unsigned int pblk_rb_read_to_bio(struct pblk_rb *rb, struct nvm_rq *rqd,
/* Release flags on context. Protect from writes */
smp_store_release(&entry->w_ctx.flags, flags);
- pos = (pos + 1) & (rb->nr_entries - 1);
+ pos = pblk_rb_ptr_wrap(rb, pos, 1);
}
if (pad) {
@@ -652,7 +657,7 @@ int pblk_rb_copy_to_bio(struct pblk_rb *rb, struct bio *bio, sector_t lba,
struct pblk_w_ctx *pblk_rb_w_ctx(struct pblk_rb *rb, unsigned int pos)
{
- unsigned int entry = pos & (rb->nr_entries - 1);
+ unsigned int entry = pblk_rb_ptr_wrap(rb, pos, 0);
return &rb->entries[entry].w_ctx;
}
@@ -698,7 +703,7 @@ unsigned int pblk_rb_sync_advance(struct pblk_rb *rb, unsigned int nr_entries)
}
}
- sync = (sync + nr_entries) & (rb->nr_entries - 1);
+ sync = pblk_rb_ptr_wrap(rb, sync, nr_entries);
/* Protect from counts */
smp_store_release(&rb->sync, sync);
diff --git a/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c
index 277abc8633f7..fa8726493b39 100644
--- a/drivers/lightnvm/pblk-write.c
+++ b/drivers/lightnvm/pblk-write.c
@@ -140,12 +140,11 @@ static void pblk_prepare_resubmit(struct pblk *pblk, unsigned int sentry,
struct pblk_w_ctx *w_ctx;
struct ppa_addr ppa_l2p;
int flags;
- unsigned int pos, i;
+ unsigned int i;
spin_lock(&pblk->trans_lock);
- pos = sentry;
for (i = 0; i < nr_entries; i++) {
- entry = &rb->entries[pos];
+ entry = &rb->entries[pblk_rb_ptr_wrap(rb, sentry, i)];
w_ctx = &entry->w_ctx;
/* Check if the lba has been overwritten */
@@ -164,8 +163,6 @@ static void pblk_prepare_resubmit(struct pblk *pblk, unsigned int sentry,
*/
line = pblk_ppa_to_line(pblk, w_ctx->ppa);
kref_put(&line->ref, pblk_line_put);
-
- pos = (pos + 1) & (rb->nr_entries - 1);
}
spin_unlock(&pblk->trans_lock);
}
diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
index e70ece87a9f4..0ffc19cff697 100644
--- a/drivers/lightnvm/pblk.h
+++ b/drivers/lightnvm/pblk.h
@@ -760,6 +760,8 @@ unsigned int pblk_rb_read_commit(struct pblk_rb *rb, unsigned int entries);
unsigned int pblk_rb_sync_init(struct pblk_rb *rb, unsigned long *flags);
unsigned int pblk_rb_sync_advance(struct pblk_rb *rb, unsigned int nr_entries);
+unsigned int pblk_rb_ptr_wrap(struct pblk_rb *rb, unsigned int p,
+ unsigned int nr_entries);
void pblk_rb_sync_end(struct pblk_rb *rb, unsigned long *flags);
unsigned int pblk_rb_flush_point_count(struct pblk_rb *rb);
--
2.7.4
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