[PATCH v9 3/5] rrpc: Round-robin sector target with cost-based gc
Matias Bjørling
m at bjorling.me
Wed Oct 14 07:42:16 PDT 2015
This target allows an Open-Channel SSD to be exposed asas a block
device.
It implements a round-robin approach for sector allocation,
together with a greedy cost-based garbage collector.
Signed-off-by: Matias Bjørling <m at bjorling.me>
---
drivers/lightnvm/Kconfig | 7 +
drivers/lightnvm/Makefile | 1 +
drivers/lightnvm/rrpc.c | 1308 +++++++++++++++++++++++++++++++++++++++++++++
drivers/lightnvm/rrpc.h | 239 +++++++++
4 files changed, 1555 insertions(+)
create mode 100644 drivers/lightnvm/rrpc.c
create mode 100644 drivers/lightnvm/rrpc.h
diff --git a/drivers/lightnvm/Kconfig b/drivers/lightnvm/Kconfig
index 2a27971..a16bf56 100644
--- a/drivers/lightnvm/Kconfig
+++ b/drivers/lightnvm/Kconfig
@@ -32,4 +32,11 @@ config NVM_GENNVM
functionality to device, while keeping data placement and garbage
collection decisions on the host.
+config NVM_RRPC
+ tristate "Round-robin Hybrid Open-Channel SSD target"
+ ---help---
+ Allows an open-channel SSD to be exposed as a block device to the
+ host. The target is implemented using a linear mapping table and
+ cost-based garbage collection. It is optimized for 4K IO sizes.
+
endif # NVM
diff --git a/drivers/lightnvm/Makefile b/drivers/lightnvm/Makefile
index e2428e0..7e0f42a 100644
--- a/drivers/lightnvm/Makefile
+++ b/drivers/lightnvm/Makefile
@@ -4,3 +4,4 @@
obj-$(CONFIG_NVM) := core.o
obj-$(CONFIG_NVM_GENNVM) += gennvm.o
+obj-$(CONFIG_NVM_RRPC) += rrpc.o
diff --git a/drivers/lightnvm/rrpc.c b/drivers/lightnvm/rrpc.c
new file mode 100644
index 0000000..7575fce
--- /dev/null
+++ b/drivers/lightnvm/rrpc.c
@@ -0,0 +1,1308 @@
+/*
+ * Copyright (C) 2015 IT University of Copenhagen
+ * Initial release: Matias Bjorling <m at bjorling.me>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * Implementation of a Round-robin page-based Hybrid FTL for Open-channel SSDs.
+ */
+
+#include "rrpc.h"
+
+static struct kmem_cache *rrpc_gcb_cache, *rrpc_rq_cache;
+static DECLARE_RWSEM(rrpc_lock);
+
+static int rrpc_submit_io(struct rrpc *rrpc, struct bio *bio,
+ struct nvm_rq *rqd, unsigned long flags);
+
+#define rrpc_for_each_lun(rrpc, rlun, i) \
+ for ((i) = 0, rlun = &(rrpc)->luns[0]; \
+ (i) < (rrpc)->nr_luns; (i)++, rlun = &(rrpc)->luns[(i)])
+
+static void rrpc_page_invalidate(struct rrpc *rrpc, struct rrpc_addr *a)
+{
+ struct rrpc_block *rblk = a->rblk;
+ unsigned int pg_offset;
+
+ lockdep_assert_held(&rrpc->rev_lock);
+
+ if (a->addr == ADDR_EMPTY || !rblk)
+ return;
+
+ spin_lock(&rblk->lock);
+
+ pg_offset = a->addr % rrpc->dev->pgs_per_blk;
+ WARN_ON(test_and_set_bit(pg_offset, rblk->invalid_pages));
+ rblk->nr_invalid_pages++;
+
+ spin_unlock(&rblk->lock);
+
+ rrpc->rev_trans_map[a->addr - rrpc->poffset].addr = ADDR_EMPTY;
+}
+
+static void rrpc_invalidate_range(struct rrpc *rrpc, sector_t slba,
+ unsigned len)
+{
+ sector_t i;
+
+ spin_lock(&rrpc->rev_lock);
+ for (i = slba; i < slba + len; i++) {
+ struct rrpc_addr *gp = &rrpc->trans_map[i];
+
+ rrpc_page_invalidate(rrpc, gp);
+ gp->rblk = NULL;
+ }
+ spin_unlock(&rrpc->rev_lock);
+}
+
+static struct nvm_rq *rrpc_inflight_laddr_acquire(struct rrpc *rrpc,
+ sector_t laddr, unsigned int pages)
+{
+ struct nvm_rq *rqd;
+ struct rrpc_inflight_rq *inf;
+
+ rqd = mempool_alloc(rrpc->rq_pool, GFP_ATOMIC);
+ if (!rqd)
+ return ERR_PTR(-ENOMEM);
+
+ inf = rrpc_get_inflight_rq(rqd);
+ if (rrpc_lock_laddr(rrpc, laddr, pages, inf)) {
+ mempool_free(rqd, rrpc->rq_pool);
+ return NULL;
+ }
+
+ return rqd;
+}
+
+static void rrpc_inflight_laddr_release(struct rrpc *rrpc, struct nvm_rq *rqd)
+{
+ struct rrpc_inflight_rq *inf = rrpc_get_inflight_rq(rqd);
+
+ rrpc_unlock_laddr(rrpc, inf);
+
+ mempool_free(rqd, rrpc->rq_pool);
+}
+
+static void rrpc_discard(struct rrpc *rrpc, struct bio *bio)
+{
+ sector_t slba = bio->bi_iter.bi_sector / NR_PHY_IN_LOG;
+ sector_t len = bio->bi_iter.bi_size / RRPC_EXPOSED_PAGE_SIZE;
+ struct nvm_rq *rqd;
+
+ do {
+ rqd = rrpc_inflight_laddr_acquire(rrpc, slba, len);
+ schedule();
+ } while (!rqd);
+
+ if (IS_ERR(rqd)) {
+ pr_err("rrpc: unable to acquire inflight IO\n");
+ bio_io_error(bio);
+ return;
+ }
+
+ rrpc_invalidate_range(rrpc, slba, len);
+ rrpc_inflight_laddr_release(rrpc, rqd);
+}
+
+static int block_is_full(struct rrpc *rrpc, struct rrpc_block *rblk)
+{
+ return (rblk->next_page == rrpc->dev->pgs_per_blk);
+}
+
+static sector_t block_to_addr(struct rrpc *rrpc, struct rrpc_block *rblk)
+{
+ struct nvm_block *blk = rblk->parent;
+
+ return blk->id * rrpc->dev->pgs_per_blk;
+}
+
+static struct ppa_addr rrpc_ppa_to_gaddr(struct nvm_dev *dev,
+ sector_t addr)
+{
+ struct ppa_addr paddr;
+
+ paddr.ppa = addr;
+ return __linear_to_generic_addr(dev, paddr);
+}
+
+/* requires lun->lock taken */
+static void rrpc_set_lun_cur(struct rrpc_lun *rlun, struct rrpc_block *rblk)
+{
+ struct rrpc *rrpc = rlun->rrpc;
+
+ BUG_ON(!rblk);
+
+ if (rlun->cur) {
+ spin_lock(&rlun->cur->lock);
+ WARN_ON(!block_is_full(rrpc, rlun->cur));
+ spin_unlock(&rlun->cur->lock);
+ }
+ rlun->cur = rblk;
+}
+
+static struct rrpc_block *rrpc_get_blk(struct rrpc *rrpc, struct rrpc_lun *rlun,
+ unsigned long flags)
+{
+ struct nvm_block *blk;
+ struct rrpc_block *rblk;
+
+ blk = nvm_get_blk(rrpc->dev, rlun->parent, 0);
+ if (!blk)
+ return NULL;
+
+ rblk = &rlun->blocks[blk->id];
+ blk->priv = rblk;
+
+ bitmap_zero(rblk->invalid_pages, rrpc->dev->pgs_per_blk);
+ rblk->next_page = 0;
+ rblk->nr_invalid_pages = 0;
+ atomic_set(&rblk->data_cmnt_size, 0);
+
+ return rblk;
+}
+
+static void rrpc_put_blk(struct rrpc *rrpc, struct rrpc_block *rblk)
+{
+ nvm_put_blk(rrpc->dev, rblk->parent);
+}
+
+static struct rrpc_lun *get_next_lun(struct rrpc *rrpc)
+{
+ int next = atomic_inc_return(&rrpc->next_lun);
+
+ return &rrpc->luns[next % rrpc->nr_luns];
+}
+
+static void rrpc_gc_kick(struct rrpc *rrpc)
+{
+ struct rrpc_lun *rlun;
+ unsigned int i;
+
+ for (i = 0; i < rrpc->nr_luns; i++) {
+ rlun = &rrpc->luns[i];
+ queue_work(rrpc->krqd_wq, &rlun->ws_gc);
+ }
+}
+
+/*
+ * timed GC every interval.
+ */
+static void rrpc_gc_timer(unsigned long data)
+{
+ struct rrpc *rrpc = (struct rrpc *)data;
+
+ rrpc_gc_kick(rrpc);
+ mod_timer(&rrpc->gc_timer, jiffies + msecs_to_jiffies(10));
+}
+
+static void rrpc_end_sync_bio(struct bio *bio)
+{
+ struct completion *waiting = bio->bi_private;
+
+ if (bio->bi_error)
+ pr_err("nvm: gc request failed (%u).\n", bio->bi_error);
+
+ complete(waiting);
+}
+
+/*
+ * rrpc_move_valid_pages -- migrate live data off the block
+ * @rrpc: the 'rrpc' structure
+ * @block: the block from which to migrate live pages
+ *
+ * Description:
+ * GC algorithms may call this function to migrate remaining live
+ * pages off the block prior to erasing it. This function blocks
+ * further execution until the operation is complete.
+ */
+static int rrpc_move_valid_pages(struct rrpc *rrpc, struct rrpc_block *rblk)
+{
+ struct request_queue *q = rrpc->dev->q;
+ struct rrpc_rev_addr *rev;
+ struct nvm_rq *rqd;
+ struct bio *bio;
+ struct page *page;
+ int slot;
+ int nr_pgs_per_blk = rrpc->dev->pgs_per_blk;
+ sector_t phys_addr;
+ DECLARE_COMPLETION_ONSTACK(wait);
+
+ if (bitmap_full(rblk->invalid_pages, nr_pgs_per_blk))
+ return 0;
+
+ bio = bio_alloc(GFP_NOIO, 1);
+ if (!bio) {
+ pr_err("nvm: could not alloc bio to gc\n");
+ return -ENOMEM;
+ }
+
+ page = mempool_alloc(rrpc->page_pool, GFP_NOIO);
+
+ while ((slot = find_first_zero_bit(rblk->invalid_pages,
+ nr_pgs_per_blk)) < nr_pgs_per_blk) {
+
+ /* Lock laddr */
+ phys_addr = (rblk->parent->id * nr_pgs_per_blk) + slot;
+
+try:
+ spin_lock(&rrpc->rev_lock);
+ /* Get logical address from physical to logical table */
+ rev = &rrpc->rev_trans_map[phys_addr - rrpc->poffset];
+ /* already updated by previous regular write */
+ if (rev->addr == ADDR_EMPTY) {
+ spin_unlock(&rrpc->rev_lock);
+ continue;
+ }
+
+ rqd = rrpc_inflight_laddr_acquire(rrpc, rev->addr, 1);
+ if (IS_ERR_OR_NULL(rqd)) {
+ spin_unlock(&rrpc->rev_lock);
+ schedule();
+ goto try;
+ }
+
+ spin_unlock(&rrpc->rev_lock);
+
+ /* Perform read to do GC */
+ bio->bi_iter.bi_sector = rrpc_get_sector(rev->addr);
+ bio->bi_rw = READ;
+ bio->bi_private = &wait;
+ bio->bi_end_io = rrpc_end_sync_bio;
+
+ /* TODO: may fail when EXP_PG_SIZE > PAGE_SIZE */
+ bio_add_pc_page(q, bio, page, RRPC_EXPOSED_PAGE_SIZE, 0);
+
+ if (rrpc_submit_io(rrpc, bio, rqd, NVM_IOTYPE_GC)) {
+ pr_err("rrpc: gc read failed.\n");
+ rrpc_inflight_laddr_release(rrpc, rqd);
+ goto finished;
+ }
+ wait_for_completion_io(&wait);
+
+ bio_reset(bio);
+ reinit_completion(&wait);
+
+ bio->bi_iter.bi_sector = rrpc_get_sector(rev->addr);
+ bio->bi_rw = WRITE;
+ bio->bi_private = &wait;
+ bio->bi_end_io = rrpc_end_sync_bio;
+
+ bio_add_pc_page(q, bio, page, RRPC_EXPOSED_PAGE_SIZE, 0);
+
+ /* turn the command around and write the data back to a new
+ * address
+ */
+ if (rrpc_submit_io(rrpc, bio, rqd, NVM_IOTYPE_GC)) {
+ pr_err("rrpc: gc write failed.\n");
+ rrpc_inflight_laddr_release(rrpc, rqd);
+ goto finished;
+ }
+ wait_for_completion_io(&wait);
+
+ rrpc_inflight_laddr_release(rrpc, rqd);
+
+ bio_reset(bio);
+ }
+
+finished:
+ mempool_free(page, rrpc->page_pool);
+ bio_put(bio);
+
+ if (!bitmap_full(rblk->invalid_pages, nr_pgs_per_blk)) {
+ pr_err("nvm: failed to garbage collect block\n");
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static void rrpc_block_gc(struct work_struct *work)
+{
+ struct rrpc_block_gc *gcb = container_of(work, struct rrpc_block_gc,
+ ws_gc);
+ struct rrpc *rrpc = gcb->rrpc;
+ struct rrpc_block *rblk = gcb->rblk;
+ struct nvm_dev *dev = rrpc->dev;
+
+ pr_debug("nvm: block '%llu' being reclaimed\n", rblk->parent->id);
+
+ if (rrpc_move_valid_pages(rrpc, rblk))
+ goto done;
+
+ nvm_erase_blk(dev, rblk->parent);
+ rrpc_put_blk(rrpc, rblk);
+done:
+ mempool_free(gcb, rrpc->gcb_pool);
+}
+
+/* the block with highest number of invalid pages, will be in the beginning
+ * of the list
+ */
+static struct rrpc_block *rblock_max_invalid(struct rrpc_block *ra,
+ struct rrpc_block *rb)
+{
+ if (ra->nr_invalid_pages == rb->nr_invalid_pages)
+ return ra;
+
+ return (ra->nr_invalid_pages < rb->nr_invalid_pages) ? rb : ra;
+}
+
+/* linearly find the block with highest number of invalid pages
+ * requires lun->lock
+ */
+static struct rrpc_block *block_prio_find_max(struct rrpc_lun *rlun)
+{
+ struct list_head *prio_list = &rlun->prio_list;
+ struct rrpc_block *rblock, *max;
+
+ BUG_ON(list_empty(prio_list));
+
+ max = list_first_entry(prio_list, struct rrpc_block, prio);
+ list_for_each_entry(rblock, prio_list, prio)
+ max = rblock_max_invalid(max, rblock);
+
+ return max;
+}
+
+static void rrpc_lun_gc(struct work_struct *work)
+{
+ struct rrpc_lun *rlun = container_of(work, struct rrpc_lun, ws_gc);
+ struct rrpc *rrpc = rlun->rrpc;
+ struct nvm_lun *lun = rlun->parent;
+ struct rrpc_block_gc *gcb;
+ unsigned int nr_blocks_need;
+
+ nr_blocks_need = rrpc->dev->blks_per_lun / GC_LIMIT_INVERSE;
+
+ if (nr_blocks_need < rrpc->nr_luns)
+ nr_blocks_need = rrpc->nr_luns;
+
+ spin_lock(&lun->lock);
+ while (nr_blocks_need > lun->nr_free_blocks &&
+ !list_empty(&rlun->prio_list)) {
+ struct rrpc_block *rblock = block_prio_find_max(rlun);
+ struct nvm_block *block = rblock->parent;
+
+ if (!rblock->nr_invalid_pages)
+ break;
+
+ list_del_init(&rblock->prio);
+
+ BUG_ON(!block_is_full(rrpc, rblock));
+
+ pr_debug("rrpc: selected block '%llu' for GC\n", block->id);
+
+ gcb = mempool_alloc(rrpc->gcb_pool, GFP_ATOMIC);
+ if (!gcb)
+ break;
+
+ gcb->rrpc = rrpc;
+ gcb->rblk = rblock;
+ INIT_WORK(&gcb->ws_gc, rrpc_block_gc);
+
+ queue_work(rrpc->kgc_wq, &gcb->ws_gc);
+
+ nr_blocks_need--;
+ }
+ spin_unlock(&lun->lock);
+
+ /* TODO: Hint that request queue can be started again */
+}
+
+static void rrpc_gc_queue(struct work_struct *work)
+{
+ struct rrpc_block_gc *gcb = container_of(work, struct rrpc_block_gc,
+ ws_gc);
+ struct rrpc *rrpc = gcb->rrpc;
+ struct rrpc_block *rblk = gcb->rblk;
+ struct nvm_lun *lun = rblk->parent->lun;
+ struct rrpc_lun *rlun = &rrpc->luns[lun->id - rrpc->lun_offset];
+
+ spin_lock(&rlun->lock);
+ list_add_tail(&rblk->prio, &rlun->prio_list);
+ spin_unlock(&rlun->lock);
+
+ mempool_free(gcb, rrpc->gcb_pool);
+ pr_debug("nvm: block '%llu' is full, allow GC (sched)\n",
+ rblk->parent->id);
+}
+
+static const struct block_device_operations rrpc_fops = {
+ .owner = THIS_MODULE,
+};
+
+static struct rrpc_lun *rrpc_get_lun_rr(struct rrpc *rrpc, int is_gc)
+{
+ unsigned int i;
+ struct rrpc_lun *rlun, *max_free;
+
+ if (!is_gc)
+ return get_next_lun(rrpc);
+
+ /* during GC, we don't care about RR, instead we want to make
+ * sure that we maintain evenness between the block luns.
+ */
+ max_free = &rrpc->luns[0];
+ /* prevent GC-ing lun from devouring pages of a lun with
+ * little free blocks. We don't take the lock as we only need an
+ * estimate.
+ */
+ rrpc_for_each_lun(rrpc, rlun, i) {
+ if (rlun->parent->nr_free_blocks >
+ max_free->parent->nr_free_blocks)
+ max_free = rlun;
+ }
+
+ return max_free;
+}
+
+static struct rrpc_addr *rrpc_update_map(struct rrpc *rrpc, sector_t laddr,
+ struct rrpc_block *rblk, sector_t paddr)
+{
+ struct rrpc_addr *gp;
+ struct rrpc_rev_addr *rev;
+
+ BUG_ON(laddr >= rrpc->nr_pages);
+
+ gp = &rrpc->trans_map[laddr];
+ spin_lock(&rrpc->rev_lock);
+ if (gp->rblk)
+ rrpc_page_invalidate(rrpc, gp);
+
+ gp->addr = paddr;
+ gp->rblk = rblk;
+
+ rev = &rrpc->rev_trans_map[gp->addr - rrpc->poffset];
+ rev->addr = laddr;
+ spin_unlock(&rrpc->rev_lock);
+
+ return gp;
+}
+
+static sector_t rrpc_alloc_addr(struct rrpc *rrpc, struct rrpc_block *rblk)
+{
+ sector_t addr = ADDR_EMPTY;
+
+ spin_lock(&rblk->lock);
+ if (block_is_full(rrpc, rblk))
+ goto out;
+
+ addr = block_to_addr(rrpc, rblk) + rblk->next_page;
+
+ rblk->next_page++;
+out:
+ spin_unlock(&rblk->lock);
+ return addr;
+}
+
+/* Simple round-robin Logical to physical address translation.
+ *
+ * Retrieve the mapping using the active append point. Then update the ap for
+ * the next write to the disk.
+ *
+ * Returns rrpc_addr with the physical address and block. Remember to return to
+ * rrpc->addr_cache when request is finished.
+ */
+static struct rrpc_addr *rrpc_map_page(struct rrpc *rrpc, sector_t laddr,
+ int is_gc)
+{
+ struct rrpc_lun *rlun;
+ struct rrpc_block *rblk;
+ struct nvm_lun *lun;
+ sector_t paddr;
+
+ rlun = rrpc_get_lun_rr(rrpc, is_gc);
+ lun = rlun->parent;
+
+ if (!is_gc && lun->nr_free_blocks < rrpc->nr_luns * 4)
+ return NULL;
+
+ spin_lock(&rlun->lock);
+
+ rblk = rlun->cur;
+retry:
+ paddr = rrpc_alloc_addr(rrpc, rblk);
+
+ if (paddr == ADDR_EMPTY) {
+ rblk = rrpc_get_blk(rrpc, rlun, 0);
+ if (rblk) {
+ rrpc_set_lun_cur(rlun, rblk);
+ goto retry;
+ }
+
+ if (is_gc) {
+ /* retry from emergency gc block */
+ paddr = rrpc_alloc_addr(rrpc, rlun->gc_cur);
+ if (paddr == ADDR_EMPTY) {
+ rblk = rrpc_get_blk(rrpc, rlun, 1);
+ if (!rblk) {
+ pr_err("rrpc: no more blocks");
+ goto err;
+ }
+
+ rlun->gc_cur = rblk;
+ paddr = rrpc_alloc_addr(rrpc, rlun->gc_cur);
+ }
+ rblk = rlun->gc_cur;
+ }
+ }
+
+ spin_unlock(&rlun->lock);
+ return rrpc_update_map(rrpc, laddr, rblk, paddr);
+err:
+ spin_unlock(&rlun->lock);
+ return NULL;
+}
+
+static void rrpc_run_gc(struct rrpc *rrpc, struct rrpc_block *rblk)
+{
+ struct rrpc_block_gc *gcb;
+
+ gcb = mempool_alloc(rrpc->gcb_pool, GFP_ATOMIC);
+ if (!gcb) {
+ pr_err("rrpc: unable to queue block for gc.");
+ return;
+ }
+
+ gcb->rrpc = rrpc;
+ gcb->rblk = rblk;
+
+ INIT_WORK(&gcb->ws_gc, rrpc_gc_queue);
+ queue_work(rrpc->kgc_wq, &gcb->ws_gc);
+}
+
+static void rrpc_end_io_write(struct rrpc *rrpc, struct rrpc_rq *rrqd,
+ sector_t laddr, uint8_t npages)
+{
+ struct rrpc_addr *p;
+ struct rrpc_block *rblk;
+ struct nvm_lun *lun;
+ int cmnt_size, i;
+
+ for (i = 0; i < npages; i++) {
+ p = &rrpc->trans_map[laddr + i];
+ rblk = p->rblk;
+ lun = rblk->parent->lun;
+
+ cmnt_size = atomic_inc_return(&rblk->data_cmnt_size);
+ if (unlikely(cmnt_size == rrpc->dev->pgs_per_blk))
+ rrpc_run_gc(rrpc, rblk);
+ }
+}
+
+static void rrpc_end_io(struct nvm_rq *rqd, int error)
+{
+ struct rrpc *rrpc = container_of(rqd->ins, struct rrpc, instance);
+ struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
+ uint8_t npages = rqd->nr_pages;
+ sector_t laddr = rrpc_get_laddr(rqd->bio) - npages;
+
+ if (bio_data_dir(rqd->bio) == WRITE)
+ rrpc_end_io_write(rrpc, rrqd, laddr, npages);
+
+ if (rrqd->flags & NVM_IOTYPE_GC)
+ return;
+
+ rrpc_unlock_rq(rrpc, rqd);
+ bio_put(rqd->bio);
+
+ if (npages > 1)
+ nvm_dev_dma_free(rrpc->dev, rqd->ppa_list, rqd->dma_ppa_list);
+ if (rqd->metadata)
+ nvm_dev_dma_free(rrpc->dev, rqd->metadata, rqd->dma_metadata);
+
+ mempool_free(rqd, rrpc->rq_pool);
+}
+
+static int rrpc_read_ppalist_rq(struct rrpc *rrpc, struct bio *bio,
+ struct nvm_rq *rqd, unsigned long flags, int npages)
+{
+ struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
+ struct rrpc_addr *gp;
+ sector_t laddr = rrpc_get_laddr(bio);
+ int is_gc = flags & NVM_IOTYPE_GC;
+ int i;
+
+ if (!is_gc && rrpc_lock_rq(rrpc, bio, rqd)) {
+ nvm_dev_dma_free(rrpc->dev, rqd->ppa_list, rqd->dma_ppa_list);
+ return NVM_IO_REQUEUE;
+ }
+
+ for (i = 0; i < npages; i++) {
+ /* We assume that mapping occurs at 4KB granularity */
+ BUG_ON(!(laddr + i >= 0 && laddr + i < rrpc->nr_pages));
+ gp = &rrpc->trans_map[laddr + i];
+
+ if (gp->rblk) {
+ rqd->ppa_list[i] = rrpc_ppa_to_gaddr(rrpc->dev,
+ gp->addr);
+ } else {
+ BUG_ON(is_gc);
+ rrpc_unlock_laddr(rrpc, r);
+ nvm_dev_dma_free(rrpc->dev, rqd->ppa_list,
+ rqd->dma_ppa_list);
+ return NVM_IO_DONE;
+ }
+ }
+
+ rqd->opcode = NVM_OP_HBREAD;
+
+ return NVM_IO_OK;
+}
+
+static int rrpc_read_rq(struct rrpc *rrpc, struct bio *bio, struct nvm_rq *rqd,
+ unsigned long flags)
+{
+ struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
+ int is_gc = flags & NVM_IOTYPE_GC;
+ sector_t laddr = rrpc_get_laddr(bio);
+ struct rrpc_addr *gp;
+
+ if (!is_gc && rrpc_lock_rq(rrpc, bio, rqd))
+ return NVM_IO_REQUEUE;
+
+ BUG_ON(!(laddr >= 0 && laddr < rrpc->nr_pages));
+ gp = &rrpc->trans_map[laddr];
+
+ if (gp->rblk) {
+ rqd->ppa_addr = rrpc_ppa_to_gaddr(rrpc->dev, gp->addr);
+ } else {
+ BUG_ON(is_gc);
+ rrpc_unlock_rq(rrpc, rqd);
+ return NVM_IO_DONE;
+ }
+
+ rqd->opcode = NVM_OP_HBREAD;
+ rrqd->addr = gp;
+
+ return NVM_IO_OK;
+}
+
+static int rrpc_write_ppalist_rq(struct rrpc *rrpc, struct bio *bio,
+ struct nvm_rq *rqd, unsigned long flags, int npages)
+{
+ struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
+ struct rrpc_addr *p;
+ sector_t laddr = rrpc_get_laddr(bio);
+ int is_gc = flags & NVM_IOTYPE_GC;
+ int i;
+
+ if (!is_gc && rrpc_lock_rq(rrpc, bio, rqd)) {
+ nvm_dev_dma_free(rrpc->dev, rqd->ppa_list, rqd->dma_ppa_list);
+ return NVM_IO_REQUEUE;
+ }
+
+ for (i = 0; i < npages; i++) {
+ /* We assume that mapping occurs at 4KB granularity */
+ p = rrpc_map_page(rrpc, laddr + i, is_gc);
+ if (!p) {
+ BUG_ON(is_gc);
+ rrpc_unlock_laddr(rrpc, r);
+ nvm_dev_dma_free(rrpc->dev, rqd->ppa_list,
+ rqd->dma_ppa_list);
+ rrpc_gc_kick(rrpc);
+ return NVM_IO_REQUEUE;
+ }
+
+ rqd->ppa_list[i] = rrpc_ppa_to_gaddr(rrpc->dev,
+ p->addr);
+ }
+
+ rqd->opcode = NVM_OP_HBWRITE;
+
+ return NVM_IO_OK;
+}
+
+static int rrpc_write_rq(struct rrpc *rrpc, struct bio *bio,
+ struct nvm_rq *rqd, unsigned long flags)
+{
+ struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
+ struct rrpc_addr *p;
+ int is_gc = flags & NVM_IOTYPE_GC;
+ sector_t laddr = rrpc_get_laddr(bio);
+
+ if (!is_gc && rrpc_lock_rq(rrpc, bio, rqd))
+ return NVM_IO_REQUEUE;
+
+ p = rrpc_map_page(rrpc, laddr, is_gc);
+ if (!p) {
+ BUG_ON(is_gc);
+ rrpc_unlock_rq(rrpc, rqd);
+ rrpc_gc_kick(rrpc);
+ return NVM_IO_REQUEUE;
+ }
+
+ rqd->ppa_addr = rrpc_ppa_to_gaddr(rrpc->dev, p->addr);
+ rqd->opcode = NVM_OP_HBWRITE;
+ rrqd->addr = p;
+
+ return NVM_IO_OK;
+}
+
+static int rrpc_setup_rq(struct rrpc *rrpc, struct bio *bio,
+ struct nvm_rq *rqd, unsigned long flags, uint8_t npages)
+{
+ if (npages > 1) {
+ rqd->ppa_list = nvm_dev_dma_alloc(rrpc->dev, GFP_KERNEL,
+ &rqd->dma_ppa_list);
+ if (!rqd->ppa_list) {
+ pr_err("rrpc: not able to allocate ppa list\n");
+ return NVM_IO_ERR;
+ }
+
+ if (bio_rw(bio) == WRITE)
+ return rrpc_write_ppalist_rq(rrpc, bio, rqd, flags,
+ npages);
+
+ return rrpc_read_ppalist_rq(rrpc, bio, rqd, flags, npages);
+ }
+
+ if (bio_rw(bio) == WRITE)
+ return rrpc_write_rq(rrpc, bio, rqd, flags);
+
+ return rrpc_read_rq(rrpc, bio, rqd, flags);
+}
+
+static int rrpc_submit_io(struct rrpc *rrpc, struct bio *bio,
+ struct nvm_rq *rqd, unsigned long flags)
+{
+ int err;
+ struct rrpc_rq *rrq = nvm_rq_to_pdu(rqd);
+ uint8_t nr_pages = rrpc_get_pages(bio);
+
+ err = rrpc_setup_rq(rrpc, bio, rqd, flags, nr_pages);
+ if (err)
+ return err;
+
+ bio_get(bio);
+ rqd->bio = bio;
+ rqd->ins = &rrpc->instance;
+ rqd->nr_pages = nr_pages;
+ rrq->flags = flags;
+
+ err = nvm_submit_io(rrpc->dev, rqd);
+ if (err) {
+ pr_err("rrpc: IO submission failed: %d\n", err);
+ return NVM_IO_ERR;
+ }
+
+ return NVM_IO_OK;
+}
+
+static void rrpc_make_rq(struct request_queue *q, struct bio *bio)
+{
+ struct rrpc *rrpc = q->queuedata;
+ struct nvm_rq *rqd;
+ int err;
+
+ if (bio->bi_rw & REQ_DISCARD) {
+ rrpc_discard(rrpc, bio);
+ return;
+ }
+
+ rqd = mempool_alloc(rrpc->rq_pool, GFP_KERNEL);
+ if (!rqd) {
+ pr_err_ratelimited("rrpc: not able to queue bio.");
+ bio_io_error(bio);
+ return;
+ }
+ memset(rqd, 0, sizeof(struct nvm_rq));
+
+ err = rrpc_submit_io(rrpc, bio, rqd, NVM_IOTYPE_NONE);
+ switch (err) {
+ case NVM_IO_OK:
+ return;
+ case NVM_IO_ERR:
+ bio_io_error(bio);
+ break;
+ case NVM_IO_DONE:
+ bio_endio(bio);
+ break;
+ case NVM_IO_REQUEUE:
+ spin_lock(&rrpc->bio_lock);
+ bio_list_add(&rrpc->requeue_bios, bio);
+ spin_unlock(&rrpc->bio_lock);
+ queue_work(rrpc->kgc_wq, &rrpc->ws_requeue);
+ break;
+ }
+
+ mempool_free(rqd, rrpc->rq_pool);
+}
+
+static void rrpc_requeue(struct work_struct *work)
+{
+ struct rrpc *rrpc = container_of(work, struct rrpc, ws_requeue);
+ struct bio_list bios;
+ struct bio *bio;
+
+ bio_list_init(&bios);
+
+ spin_lock(&rrpc->bio_lock);
+ bio_list_merge(&bios, &rrpc->requeue_bios);
+ bio_list_init(&rrpc->requeue_bios);
+ spin_unlock(&rrpc->bio_lock);
+
+ while ((bio = bio_list_pop(&bios)))
+ rrpc_make_rq(rrpc->disk->queue, bio);
+}
+
+static void rrpc_gc_free(struct rrpc *rrpc)
+{
+ struct rrpc_lun *rlun;
+ int i;
+
+ if (rrpc->krqd_wq)
+ destroy_workqueue(rrpc->krqd_wq);
+
+ if (rrpc->kgc_wq)
+ destroy_workqueue(rrpc->kgc_wq);
+
+ if (!rrpc->luns)
+ return;
+
+ for (i = 0; i < rrpc->nr_luns; i++) {
+ rlun = &rrpc->luns[i];
+
+ if (!rlun->blocks)
+ break;
+ vfree(rlun->blocks);
+ }
+}
+
+static int rrpc_gc_init(struct rrpc *rrpc)
+{
+ rrpc->krqd_wq = alloc_workqueue("rrpc-lun", WQ_MEM_RECLAIM|WQ_UNBOUND,
+ rrpc->nr_luns);
+ if (!rrpc->krqd_wq)
+ return -ENOMEM;
+
+ rrpc->kgc_wq = alloc_workqueue("rrpc-bg", WQ_MEM_RECLAIM, 1);
+ if (!rrpc->kgc_wq)
+ return -ENOMEM;
+
+ setup_timer(&rrpc->gc_timer, rrpc_gc_timer, (unsigned long)rrpc);
+
+ return 0;
+}
+
+static void rrpc_map_free(struct rrpc *rrpc)
+{
+ vfree(rrpc->rev_trans_map);
+ vfree(rrpc->trans_map);
+}
+
+static int rrpc_l2p_update(u64 slba, u64 nlb, u64 *entries, void *private)
+{
+ struct rrpc *rrpc = (struct rrpc *)private;
+ struct nvm_dev *dev = rrpc->dev;
+ struct rrpc_addr *addr = rrpc->trans_map + slba;
+ struct rrpc_rev_addr *raddr = rrpc->rev_trans_map;
+ sector_t max_pages = dev->total_pages * (dev->sec_size >> 9);
+ u64 elba = slba + nlb;
+ u64 i;
+
+ if (unlikely(elba > dev->total_pages)) {
+ pr_err("nvm: L2P data from device is out of bounds!\n");
+ return -EINVAL;
+ }
+
+ for (i = 0; i < nlb; i++) {
+ u64 pba = le64_to_cpu(entries[i]);
+ /* LNVM treats address-spaces as silos, LBA and PBA are
+ * equally large and zero-indexed.
+ */
+ if (unlikely(pba >= max_pages && pba != U64_MAX)) {
+ pr_err("nvm: L2P data entry is out of bounds!\n");
+ return -EINVAL;
+ }
+
+ /* Address zero is a special one. The first page on a disk is
+ * protected. As it often holds internal device boot
+ * information.
+ */
+ if (!pba)
+ continue;
+
+ addr[i].addr = pba;
+ raddr[pba].addr = slba + i;
+ }
+
+ return 0;
+}
+
+static int rrpc_map_init(struct rrpc *rrpc)
+{
+ struct nvm_dev *dev = rrpc->dev;
+ sector_t i;
+ int ret;
+
+ rrpc->trans_map = vzalloc(sizeof(struct rrpc_addr) * rrpc->nr_pages);
+ if (!rrpc->trans_map)
+ return -ENOMEM;
+
+ rrpc->rev_trans_map = vmalloc(sizeof(struct rrpc_rev_addr)
+ * rrpc->nr_pages);
+ if (!rrpc->rev_trans_map)
+ return -ENOMEM;
+
+ for (i = 0; i < rrpc->nr_pages; i++) {
+ struct rrpc_addr *p = &rrpc->trans_map[i];
+ struct rrpc_rev_addr *r = &rrpc->rev_trans_map[i];
+
+ p->addr = ADDR_EMPTY;
+ r->addr = ADDR_EMPTY;
+ }
+
+ if (!dev->ops->get_l2p_tbl)
+ return 0;
+
+ /* Bring up the mapping table from device */
+ ret = dev->ops->get_l2p_tbl(dev->q, 0, dev->total_pages,
+ rrpc_l2p_update, rrpc);
+ if (ret) {
+ pr_err("nvm: rrpc: could not read L2P table.\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+
+/* Minimum pages needed within a lun */
+#define PAGE_POOL_SIZE 16
+#define ADDR_POOL_SIZE 64
+
+static int rrpc_core_init(struct rrpc *rrpc)
+{
+ down_write(&rrpc_lock);
+ if (!rrpc_gcb_cache) {
+ rrpc_gcb_cache = kmem_cache_create("rrpc_gcb",
+ sizeof(struct rrpc_block_gc), 0, 0, NULL);
+ if (!rrpc_gcb_cache) {
+ up_write(&rrpc_lock);
+ return -ENOMEM;
+ }
+
+ rrpc_rq_cache = kmem_cache_create("rrpc_rq",
+ sizeof(struct nvm_rq) + sizeof(struct rrpc_rq),
+ 0, 0, NULL);
+ if (!rrpc_rq_cache) {
+ kmem_cache_destroy(rrpc_gcb_cache);
+ up_write(&rrpc_lock);
+ return -ENOMEM;
+ }
+ }
+ up_write(&rrpc_lock);
+
+ rrpc->page_pool = mempool_create_page_pool(PAGE_POOL_SIZE, 0);
+ if (!rrpc->page_pool)
+ return -ENOMEM;
+
+ rrpc->gcb_pool = mempool_create_slab_pool(rrpc->dev->nr_luns,
+ rrpc_gcb_cache);
+ if (!rrpc->gcb_pool)
+ return -ENOMEM;
+
+ rrpc->rq_pool = mempool_create_slab_pool(64, rrpc_rq_cache);
+ if (!rrpc->rq_pool)
+ return -ENOMEM;
+
+ spin_lock_init(&rrpc->inflights.lock);
+ INIT_LIST_HEAD(&rrpc->inflights.reqs);
+
+ return 0;
+}
+
+static void rrpc_core_free(struct rrpc *rrpc)
+{
+ mempool_destroy(rrpc->page_pool);
+ mempool_destroy(rrpc->gcb_pool);
+ mempool_destroy(rrpc->rq_pool);
+}
+
+static void rrpc_luns_free(struct rrpc *rrpc)
+{
+ kfree(rrpc->luns);
+}
+
+static int rrpc_luns_init(struct rrpc *rrpc, int lun_begin, int lun_end)
+{
+ struct nvm_dev *dev = rrpc->dev;
+ struct rrpc_lun *rlun;
+ int i, j;
+
+ spin_lock_init(&rrpc->rev_lock);
+
+ rrpc->luns = kcalloc(rrpc->nr_luns, sizeof(struct rrpc_lun),
+ GFP_KERNEL);
+ if (!rrpc->luns)
+ return -ENOMEM;
+
+ /* 1:1 mapping */
+ for (i = 0; i < rrpc->nr_luns; i++) {
+ struct nvm_lun *lun = dev->mt->get_lun(dev, lun_begin + i);
+
+ if (dev->pgs_per_blk >
+ MAX_INVALID_PAGES_STORAGE * BITS_PER_LONG) {
+ pr_err("rrpc: number of pages per block too high.");
+ goto err;
+ }
+
+ rlun = &rrpc->luns[i];
+ rlun->rrpc = rrpc;
+ rlun->parent = lun;
+ INIT_LIST_HEAD(&rlun->prio_list);
+ INIT_WORK(&rlun->ws_gc, rrpc_lun_gc);
+ spin_lock_init(&rlun->lock);
+
+ rrpc->total_blocks += dev->blks_per_lun;
+ rrpc->nr_pages += dev->sec_per_lun;
+
+ rlun->blocks = vzalloc(sizeof(struct rrpc_block) *
+ rrpc->dev->blks_per_lun);
+ if (!rlun->blocks)
+ goto err;
+
+ for (j = 0; j < rrpc->dev->blks_per_lun; j++) {
+ struct rrpc_block *rblk = &rlun->blocks[j];
+ struct nvm_block *blk = &lun->blocks[j];
+
+ rblk->parent = blk;
+ INIT_LIST_HEAD(&rblk->prio);
+ spin_lock_init(&rblk->lock);
+ }
+ }
+
+ return 0;
+err:
+ return -ENOMEM;
+}
+
+static void rrpc_free(struct rrpc *rrpc)
+{
+ rrpc_gc_free(rrpc);
+ rrpc_map_free(rrpc);
+ rrpc_core_free(rrpc);
+ rrpc_luns_free(rrpc);
+
+ kfree(rrpc);
+}
+
+static void rrpc_exit(void *private)
+{
+ struct rrpc *rrpc = private;
+
+ del_timer(&rrpc->gc_timer);
+
+ flush_workqueue(rrpc->krqd_wq);
+ flush_workqueue(rrpc->kgc_wq);
+
+ rrpc_free(rrpc);
+}
+
+static sector_t rrpc_capacity(void *private)
+{
+ struct rrpc *rrpc = private;
+ struct nvm_dev *dev = rrpc->dev;
+ sector_t reserved;
+
+ /* cur, gc, and two emergency blocks for each lun */
+ reserved = rrpc->nr_luns * dev->max_pages_per_blk * 4;
+
+ if (reserved > rrpc->nr_pages) {
+ pr_err("rrpc: not enough space available to expose storage.\n");
+ return 0;
+ }
+
+ return ((rrpc->nr_pages - reserved) / 10) * 9 * NR_PHY_IN_LOG;
+}
+
+/*
+ * Looks up the logical address from reverse trans map and check if its valid by
+ * comparing the logical to physical address with the physical address.
+ * Returns 0 on free, otherwise 1 if in use
+ */
+static void rrpc_block_map_update(struct rrpc *rrpc, struct rrpc_block *rblk)
+{
+ struct nvm_dev *dev = rrpc->dev;
+ int offset;
+ struct rrpc_addr *laddr;
+ sector_t paddr, pladdr;
+
+ for (offset = 0; offset < dev->pgs_per_blk; offset++) {
+ paddr = block_to_addr(rrpc, rblk) + offset;
+
+ pladdr = rrpc->rev_trans_map[paddr].addr;
+ if (pladdr == ADDR_EMPTY)
+ continue;
+
+ laddr = &rrpc->trans_map[pladdr];
+
+ if (paddr == laddr->addr) {
+ laddr->rblk = rblk;
+ } else {
+ set_bit(offset, rblk->invalid_pages);
+ rblk->nr_invalid_pages++;
+ }
+ }
+}
+
+static int rrpc_blocks_init(struct rrpc *rrpc)
+{
+ struct rrpc_lun *rlun;
+ struct rrpc_block *rblk;
+ int lun_iter, blk_iter;
+
+ for (lun_iter = 0; lun_iter < rrpc->nr_luns; lun_iter++) {
+ rlun = &rrpc->luns[lun_iter];
+
+ for (blk_iter = 0; blk_iter < rrpc->dev->blks_per_lun;
+ blk_iter++) {
+ rblk = &rlun->blocks[blk_iter];
+ rrpc_block_map_update(rrpc, rblk);
+ }
+ }
+
+ return 0;
+}
+
+static int rrpc_luns_configure(struct rrpc *rrpc)
+{
+ struct rrpc_lun *rlun;
+ struct rrpc_block *rblk;
+ int i;
+
+ for (i = 0; i < rrpc->nr_luns; i++) {
+ rlun = &rrpc->luns[i];
+
+ rblk = rrpc_get_blk(rrpc, rlun, 0);
+ if (!rblk)
+ return -EINVAL;
+
+ rrpc_set_lun_cur(rlun, rblk);
+
+ /* Emergency gc block */
+ rblk = rrpc_get_blk(rrpc, rlun, 1);
+ if (!rblk)
+ return -EINVAL;
+ rlun->gc_cur = rblk;
+ }
+
+ return 0;
+}
+
+static struct nvm_tgt_type tt_rrpc;
+
+static void *rrpc_init(struct nvm_dev *dev, struct gendisk *tdisk,
+ int lun_begin, int lun_end)
+{
+ struct request_queue *bqueue = dev->q;
+ struct request_queue *tqueue = tdisk->queue;
+ struct rrpc *rrpc;
+ int ret;
+
+ rrpc = kzalloc(sizeof(struct rrpc), GFP_KERNEL);
+ if (!rrpc)
+ return ERR_PTR(-ENOMEM);
+
+ rrpc->instance.tt = &tt_rrpc;
+ rrpc->dev = dev;
+ rrpc->disk = tdisk;
+
+ bio_list_init(&rrpc->requeue_bios);
+ spin_lock_init(&rrpc->bio_lock);
+ INIT_WORK(&rrpc->ws_requeue, rrpc_requeue);
+
+ rrpc->nr_luns = lun_end - lun_begin + 1;
+
+ /* simple round-robin strategy */
+ atomic_set(&rrpc->next_lun, -1);
+
+ ret = rrpc_luns_init(rrpc, lun_begin, lun_end);
+ if (ret) {
+ pr_err("nvm: could not initialize luns\n");
+ goto err;
+ }
+
+ rrpc->poffset = dev->sec_per_lun * lun_begin;
+ rrpc->lun_offset = lun_begin;
+
+ ret = rrpc_core_init(rrpc);
+ if (ret) {
+ pr_err("nvm: rrpc: could not initialize core\n");
+ goto err;
+ }
+
+ ret = rrpc_map_init(rrpc);
+ if (ret) {
+ pr_err("nvm: rrpc: could not initialize maps\n");
+ goto err;
+ }
+
+ ret = rrpc_blocks_init(rrpc);
+ if (ret) {
+ pr_err("nvm: rrpc: could not initialize state for blocks\n");
+ goto err;
+ }
+
+ ret = rrpc_luns_configure(rrpc);
+ if (ret) {
+ pr_err("nvm: rrpc: not enough blocks available in LUNs.\n");
+ goto err;
+ }
+
+ ret = rrpc_gc_init(rrpc);
+ if (ret) {
+ pr_err("nvm: rrpc: could not initialize gc\n");
+ goto err;
+ }
+
+ /* inherit the size from the underlying device */
+ blk_queue_logical_block_size(tqueue, queue_physical_block_size(bqueue));
+ blk_queue_max_hw_sectors(tqueue, queue_max_hw_sectors(bqueue));
+
+ pr_info("nvm: rrpc initialized with %u luns and %llu pages.\n",
+ rrpc->nr_luns, (unsigned long long)rrpc->nr_pages);
+
+ mod_timer(&rrpc->gc_timer, jiffies + msecs_to_jiffies(10));
+
+ return rrpc;
+err:
+ rrpc_free(rrpc);
+ return ERR_PTR(ret);
+}
+
+/* round robin, page-based FTL, and cost-based GC */
+static struct nvm_tgt_type tt_rrpc = {
+ .name = "rrpc",
+ .version = {1, 0, 0},
+
+ .make_rq = rrpc_make_rq,
+ .capacity = rrpc_capacity,
+ .end_io = rrpc_end_io,
+
+ .init = rrpc_init,
+ .exit = rrpc_exit,
+};
+
+static int __init rrpc_module_init(void)
+{
+ return nvm_register_target(&tt_rrpc);
+}
+
+static void rrpc_module_exit(void)
+{
+ nvm_unregister_target(&tt_rrpc);
+}
+
+module_init(rrpc_module_init);
+module_exit(rrpc_module_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Hybrid Target for Open-Channel SSDs");
diff --git a/drivers/lightnvm/rrpc.h b/drivers/lightnvm/rrpc.h
new file mode 100644
index 0000000..d20c844
--- /dev/null
+++ b/drivers/lightnvm/rrpc.h
@@ -0,0 +1,239 @@
+/*
+ * Copyright (C) 2015 IT University of Copenhagen
+ * Initial release: Matias Bjorling <m at bjorling.me>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * Implementation of a Round-robin page-based Hybrid FTL for Open-channel SSDs.
+ */
+
+#ifndef RRPC_H_
+#define RRPC_H_
+
+#include <linux/blkdev.h>
+#include <linux/blk-mq.h>
+#include <linux/bio.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/vmalloc.h>
+
+#include <linux/lightnvm.h>
+
+/* Run only GC if less than 1/X blocks are free */
+#define GC_LIMIT_INVERSE 10
+#define GC_TIME_SECS 100
+
+#define RRPC_SECTOR (512)
+#define RRPC_EXPOSED_PAGE_SIZE (4096)
+
+#define NR_PHY_IN_LOG (RRPC_EXPOSED_PAGE_SIZE / RRPC_SECTOR)
+
+struct rrpc_inflight {
+ struct list_head reqs;
+ spinlock_t lock;
+};
+
+struct rrpc_inflight_rq {
+ struct list_head list;
+ sector_t l_start;
+ sector_t l_end;
+};
+
+struct rrpc_rq {
+ struct rrpc_inflight_rq inflight_rq;
+ struct rrpc_addr *addr;
+ unsigned long flags;
+};
+
+struct rrpc_block {
+ struct nvm_block *parent;
+ struct list_head prio;
+
+#define MAX_INVALID_PAGES_STORAGE 8
+ /* Bitmap for invalid page intries */
+ unsigned long invalid_pages[MAX_INVALID_PAGES_STORAGE];
+ /* points to the next writable page within a block */
+ unsigned int next_page;
+ /* number of pages that are invalid, wrt host page size */
+ unsigned int nr_invalid_pages;
+
+ spinlock_t lock;
+ atomic_t data_cmnt_size; /* data pages committed to stable storage */
+};
+
+struct rrpc_lun {
+ struct rrpc *rrpc;
+ struct nvm_lun *parent;
+ struct rrpc_block *cur, *gc_cur;
+ struct rrpc_block *blocks; /* Reference to block allocation */
+ struct list_head prio_list; /* Blocks that may be GC'ed */
+ struct work_struct ws_gc;
+
+ spinlock_t lock;
+};
+
+struct rrpc {
+ /* instance must be kept in top to resolve rrpc in unprep */
+ struct nvm_tgt_instance instance;
+
+ struct nvm_dev *dev;
+ struct gendisk *disk;
+
+ sector_t poffset; /* physical page offset */
+ int lun_offset;
+
+ int nr_luns;
+ struct rrpc_lun *luns;
+
+ /* calculated values */
+ unsigned long nr_pages;
+ unsigned long total_blocks;
+
+ /* Write strategy variables. Move these into each for structure for each
+ * strategy
+ */
+ atomic_t next_lun; /* Whenever a page is written, this is updated
+ * to point to the next write lun
+ */
+
+ spinlock_t bio_lock;
+ struct bio_list requeue_bios;
+ struct work_struct ws_requeue;
+
+ /* Simple translation map of logical addresses to physical addresses.
+ * The logical addresses is known by the host system, while the physical
+ * addresses are used when writing to the disk block device.
+ */
+ struct rrpc_addr *trans_map;
+ /* also store a reverse map for garbage collection */
+ struct rrpc_rev_addr *rev_trans_map;
+ spinlock_t rev_lock;
+
+ struct rrpc_inflight inflights;
+
+ mempool_t *addr_pool;
+ mempool_t *page_pool;
+ mempool_t *gcb_pool;
+ mempool_t *rq_pool;
+
+ struct timer_list gc_timer;
+ struct workqueue_struct *krqd_wq;
+ struct workqueue_struct *kgc_wq;
+};
+
+struct rrpc_block_gc {
+ struct rrpc *rrpc;
+ struct rrpc_block *rblk;
+ struct work_struct ws_gc;
+};
+
+/* Logical to physical mapping */
+struct rrpc_addr {
+ sector_t addr;
+ struct rrpc_block *rblk;
+};
+
+/* Physical to logical mapping */
+struct rrpc_rev_addr {
+ sector_t addr;
+};
+
+static inline sector_t rrpc_get_laddr(struct bio *bio)
+{
+ return bio->bi_iter.bi_sector / NR_PHY_IN_LOG;
+}
+
+static inline unsigned int rrpc_get_pages(struct bio *bio)
+{
+ return bio->bi_iter.bi_size / RRPC_EXPOSED_PAGE_SIZE;
+}
+
+static inline sector_t rrpc_get_sector(sector_t laddr)
+{
+ return laddr * NR_PHY_IN_LOG;
+}
+
+static inline int request_intersects(struct rrpc_inflight_rq *r,
+ sector_t laddr_start, sector_t laddr_end)
+{
+ return (laddr_end >= r->l_start && laddr_end <= r->l_end) &&
+ (laddr_start >= r->l_start && laddr_start <= r->l_end);
+}
+
+static int __rrpc_lock_laddr(struct rrpc *rrpc, sector_t laddr,
+ unsigned pages, struct rrpc_inflight_rq *r)
+{
+ sector_t laddr_end = laddr + pages - 1;
+ struct rrpc_inflight_rq *rtmp;
+
+ spin_lock_irq(&rrpc->inflights.lock);
+ list_for_each_entry(rtmp, &rrpc->inflights.reqs, list) {
+ if (unlikely(request_intersects(rtmp, laddr, laddr_end))) {
+ /* existing, overlapping request, come back later */
+ spin_unlock_irq(&rrpc->inflights.lock);
+ return 1;
+ }
+ }
+
+ r->l_start = laddr;
+ r->l_end = laddr_end;
+
+ list_add_tail(&r->list, &rrpc->inflights.reqs);
+ spin_unlock_irq(&rrpc->inflights.lock);
+ return 0;
+}
+
+static inline int rrpc_lock_laddr(struct rrpc *rrpc, sector_t laddr,
+ unsigned pages,
+ struct rrpc_inflight_rq *r)
+{
+ BUG_ON((laddr + pages) > rrpc->nr_pages);
+
+ return __rrpc_lock_laddr(rrpc, laddr, pages, r);
+}
+
+static inline struct rrpc_inflight_rq *rrpc_get_inflight_rq(struct nvm_rq *rqd)
+{
+ struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
+
+ return &rrqd->inflight_rq;
+}
+
+static inline int rrpc_lock_rq(struct rrpc *rrpc, struct bio *bio,
+ struct nvm_rq *rqd)
+{
+ sector_t laddr = rrpc_get_laddr(bio);
+ unsigned int pages = rrpc_get_pages(bio);
+ struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
+
+ return rrpc_lock_laddr(rrpc, laddr, pages, r);
+}
+
+static inline void rrpc_unlock_laddr(struct rrpc *rrpc,
+ struct rrpc_inflight_rq *r)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&rrpc->inflights.lock, flags);
+ list_del_init(&r->list);
+ spin_unlock_irqrestore(&rrpc->inflights.lock, flags);
+}
+
+static inline void rrpc_unlock_rq(struct rrpc *rrpc, struct nvm_rq *rqd)
+{
+ struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
+ uint8_t pages = rqd->nr_pages;
+
+ BUG_ON((r->l_start + pages) > rrpc->nr_pages);
+
+ rrpc_unlock_laddr(rrpc, r);
+}
+
+#endif /* RRPC_H_ */
--
2.1.4
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