From 40b8657dcc0bbd4a293cac1acd4b0b01c0359416 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Javier=20Gonz=C3=A1lez?= Date: Tue, 9 Oct 2018 13:12:09 +0200 Subject: [PATCH] lightnvm: pblk: encapsulate rb pointer operations MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Matias Bjørling Signed-off-by: Jens Axboe --- 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 @@ try: /* 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 @@ out: 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 22586b78198a..7660811aa8af 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); -- 2.30.2