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

[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 <rakesh@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

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

[Javier González]

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> On 1 Oct 2017, at 15.23, Rakesh Pandit <rakesh@tuxera.com> wrote:
> 
> We already pass the structure pointer so no need to pass the member.
> 
> Signed-off-by: Rakesh Pandit <rakesh@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

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 <javier@cnexlabs.com>


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

[Javier González]

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> On 2 Oct 2017, at 13.32, Javier González <jg@lightnvm.io> wrote:
> 
>> On 1 Oct 2017, at 15.23, Rakesh Pandit <rakesh@tuxera.com> wrote:
>> 
>> We already pass the structure pointer so no need to pass the member.
>> 
>> Signed-off-by: Rakesh Pandit <rakesh@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);

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.

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

[Rakesh Pandit]

On Mon, Oct 02, 2017 at 05:16:57PM +0200, Javier González wrote:
> > On 2 Oct 2017, at 13.32, Javier González <jg@lightnvm.io> wrote:
> > 
> >> On 1 Oct 2017, at 15.23, Rakesh Pandit <rakesh@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,