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

From	Rakesh Pandit <rakesh@tuxera.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 2/6] lightnvm: pblk: reduce arguments in __pblk_rb_update_l2p
Date	2017-10-02 22:50 +0200
Message-ID	<uwfPk-ur-289@gated-at.bofh.it> (permalink)
References	<uvMtI-2Hh-15@gated-at.bofh.it> <uw7eO-6IZ-17@gated-at.bofh.it> <uwfPf-ur-229@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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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,

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[PATCH 2/6] lightnvm: pblk: reduce arguments in __pblk_rb_update_l2p Rakesh Pandit <rakesh@tuxera.com> - 2017-10-01 15:30 +0200
  Re: [PATCH 2/6] lightnvm: pblk: reduce arguments in  __pblk_rb_update_l2p Javier González <jg@lightnvm.io> - 2017-10-02 13:40 +0200
    Re: [PATCH 2/6] lightnvm: pblk: reduce arguments in  __pblk_rb_update_l2p Javier González <jg@lightnvm.io> - 2017-10-02 22:50 +0200
      Re: [PATCH 2/6] lightnvm: pblk: reduce arguments in  __pblk_rb_update_l2p Rakesh Pandit <rakesh@tuxera.com> - 2017-10-02 22:50 +0200

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