[PATCH 2/6] lightnvm: pblk: reduce arguments in __pblk_rb_update_l2p

[Rakesh Pandit]

We already pass the structure pointer so no need to pass the member.

Signed-off-by: Rakesh Pandit <rak...@tuxera.com>
---
drivers/lightnvm/pblk-rb.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/lightnvm/pblk-rb.c b/drivers/lightnvm/pblk-rb.c
index 05e6b2e..920ffac 100644
--- a/drivers/lightnvm/pblk-rb.c
+++ b/drivers/lightnvm/pblk-rb.c
@@ -201,9 +201,9 @@ unsigned int pblk_rb_read_commit(struct pblk_rb *rb, unsigned int nr_entries)
return subm;
}

-static int __pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int *l2p_upd,
- unsigned int to_update)
+static int __pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int to_update)
{
+ unsigned int l2p_update = rb->l2p_update;
struct pblk *pblk = container_of(rb, struct pblk, rwb);
struct pblk_line *line;
struct pblk_rb_entry *entry;
@@ -213,7 +213,7 @@ static int __pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int *l2p_upd,
int flags;

for (i = 0; i < to_update; i++) {
- entry = &rb->entries[*l2p_upd];
+ entry = &rb->entries[l2p_update];
w_ctx = &entry->w_ctx;

flags = READ_ONCE(entry->w_ctx.flags);
@@ -230,7 +230,7 @@ static int __pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int *l2p_upd,
line = &pblk->lines[pblk_tgt_ppa_to_line(w_ctx->ppa)];
kref_put(&line->ref, pblk_line_put);
clean_wctx(w_ctx);
- *l2p_upd = (*l2p_upd + 1) & (rb->nr_entries - 1);
+ rb->l2p_update = (l2p_update + 1) & (rb->nr_entries - 1);
}

pblk_rl_out(&pblk->rl, user_io, gc_io);
@@ -258,7 +258,7 @@ static int pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int nr_entries,

count = nr_entries - space;
/* l2p_update used exclusively under rb->w_lock */
- ret = __pblk_rb_update_l2p(rb, &rb->l2p_update, count);
+ ret = __pblk_rb_update_l2p(rb, count);

out:
return ret;
@@ -280,7 +280,7 @@ void pblk_rb_sync_l2p(struct pblk_rb *rb)
sync = smp_load_acquire(&rb->sync);

to_update = pblk_rb_ring_count(sync, rb->l2p_update, rb->nr_entries);
- __pblk_rb_update_l2p(rb, &rb->l2p_update, to_update);
+ __pblk_rb_update_l2p(rb, to_update);

spin_unlock(&rb->w_lock);
}
--
2.7.4

[Javier González]

This in inherited from the time when the buffer pointers where kept in a
separate structure. While they are kept in struct pblk_rb, this is a
good cleanup.

Reviewed-by: Javier González <jav...@cnexlabs.com>

[Rakesh Pandit]

On Mon, Oct 02, 2017 at 05:16:57PM +0200, Javier González wrote:

> > On 2 Oct 2017, at 13.32, Javier González <j...@lightnvm.io> wrote:
> >
> >> On 1 Oct 2017, at 15.23, Rakesh Pandit <rak...@tuxera.com> wrote:

[..]

> >> -static int __pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int *l2p_upd,
> >> - unsigned int to_update)
> >> +static int __pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int to_update)
> >> {
> >> + unsigned int l2p_update = rb->l2p_update;
> >> struct pblk *pblk = container_of(rb, struct pblk, rwb);
> >> struct pblk_line *line;
> >> struct pblk_rb_entry *entry;
> >> @@ -213,7 +213,7 @@ static int __pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int *l2p_upd,
> >> int flags;
> >>
> >> for (i = 0; i < to_update; i++) {
> >> - entry = &rb->entries[*l2p_upd];
> >> + entry = &rb->entries[l2p_update];
> >> w_ctx = &entry->w_ctx;
> >>
> >> flags = READ_ONCE(entry->w_ctx.flags);
> >> @@ -230,7 +230,7 @@ static int __pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int *l2p_upd,
> >> line = &pblk->lines[pblk_tgt_ppa_to_line(w_ctx->ppa)];
> >> kref_put(&line->ref, pblk_line_put);
> >> clean_wctx(w_ctx);
> >> - *l2p_upd = (*l2p_upd + 1) & (rb->nr_entries - 1);
> >> + rb->l2p_update = (l2p_update + 1) & (rb->nr_entries - 1);
>

> This is wrong. It should be rb->l2p_update when doing +1, otherwise you
> are not using the updated l2p_update value. The result is the pipeline
> stalling as the l2p pointer is left behind.
>
> I'll fix it when picking it up.
>
> Please test the patches before submitting.

Thanks for fixing it. I would be more careful. And will make sure
everything goes through testing before.

Regards,

[Javier González]

> On 2 Oct 2017, at 13.32, Javier González <j...@lightnvm.io> wrote:
>

This is wrong. It should be rb->l2p_update when doing +1, otherwise you
are not using the updated l2p_update value. The result is the pipeline
stalling as the l2p pointer is left behind.

I'll fix it when picking it up.

Please test the patches before submitting.

Javier.