1 files changed, 85 insertions, 254 deletions

diff --git a/drivers/lightnvm/pblk-read.c b/drivers/lightnvm/pblk-read.c
index f5f155d540e2..d98ea392fe33 100644
--- a/drivers/lightnvm/pblk-read.c
+++ b/drivers/lightnvm/pblk-read.c
@@ -26,8 +26,7 @@
  * issued.
  */
 static int pblk_read_from_cache(struct pblk *pblk, struct bio *bio,
-				sector_t lba, struct ppa_addr ppa,
-				int bio_iter, bool advanced_bio)
+				sector_t lba, struct ppa_addr ppa)
 {
 #ifdef CONFIG_NVM_PBLK_DEBUG
 	/* Callers must ensure that the ppa points to a cache address */
@@ -35,73 +34,75 @@ static int pblk_read_from_cache(struct pblk *pblk, struct bio *bio,
 	BUG_ON(!pblk_addr_in_cache(ppa));
 #endif
 
-	return pblk_rb_copy_to_bio(&pblk->rwb, bio, lba, ppa,
-						bio_iter, advanced_bio);
+	return pblk_rb_copy_to_bio(&pblk->rwb, bio, lba, ppa);
 }
 
-static void pblk_read_ppalist_rq(struct pblk *pblk, struct nvm_rq *rqd,
+static int pblk_read_ppalist_rq(struct pblk *pblk, struct nvm_rq *rqd,
 				 struct bio *bio, sector_t blba,
-				 unsigned long *read_bitmap)
+				 bool *from_cache)
 {
 	void *meta_list = rqd->meta_list;
-	struct ppa_addr ppas[NVM_MAX_VLBA];
-	int nr_secs = rqd->nr_ppas;
-	bool advanced_bio = false;
-	int i, j = 0;
+	int nr_secs, i;
 
-	pblk_lookup_l2p_seq(pblk, ppas, blba, nr_secs);
+retry:
+	nr_secs = pblk_lookup_l2p_seq(pblk, rqd->ppa_list, blba, rqd->nr_ppas,
+					from_cache);
+
+	if (!*from_cache)
+		goto end;
 
 	for (i = 0; i < nr_secs; i++) {
-		struct ppa_addr p = ppas[i];
 		struct pblk_sec_meta *meta = pblk_get_meta(pblk, meta_list, i);
 		sector_t lba = blba + i;
 
-retry:
-		if (pblk_ppa_empty(p)) {
+		if (pblk_ppa_empty(rqd->ppa_list[i])) {
 			__le64 addr_empty = cpu_to_le64(ADDR_EMPTY);
 
-			WARN_ON(test_and_set_bit(i, read_bitmap));
 			meta->lba = addr_empty;
-
-			if (unlikely(!advanced_bio)) {
-				bio_advance(bio, (i) * PBLK_EXPOSED_PAGE_SIZE);
-				advanced_bio = true;
+		} else if (pblk_addr_in_cache(rqd->ppa_list[i])) {
+			/*
+			 * Try to read from write buffer. The address is later
+			 * checked on the write buffer to prevent retrieving
+			 * overwritten data.
+			 */
+			if (!pblk_read_from_cache(pblk, bio, lba,
+							rqd->ppa_list[i])) {
+				if (i == 0) {
+					/*
+					 * We didn't call with bio_advance()
+					 * yet, so we can just retry.
+					 */
+					goto retry;
+				} else {
+					/*
+					 * We already call bio_advance()
+					 * so we cannot retry and we need
+					 * to quit that function in order
+					 * to allow caller to handle the bio
+					 * splitting in the current sector
+					 * position.
+					 */
+					nr_secs = i;
+					goto end;
+				}
 			}
-
-			goto next;
-		}
-
-		/* Try to read from write buffer. The address is later checked
-		 * on the write buffer to prevent retrieving overwritten data.
-		 */
-		if (pblk_addr_in_cache(p)) {
-			if (!pblk_read_from_cache(pblk, bio, lba, p, i,
-								advanced_bio)) {
-				pblk_lookup_l2p_seq(pblk, &p, lba, 1);
-				goto retry;
-			}
-			WARN_ON(test_and_set_bit(i, read_bitmap));
 			meta->lba = cpu_to_le64(lba);
-			advanced_bio = true;
 #ifdef CONFIG_NVM_PBLK_DEBUG
 			atomic_long_inc(&pblk->cache_reads);
 #endif
-		} else {
-			/* Read from media non-cached sectors */
-			rqd->ppa_list[j++] = p;
 		}
-
-next:
-		if (advanced_bio)
-			bio_advance(bio, PBLK_EXPOSED_PAGE_SIZE);
+		bio_advance(bio, PBLK_EXPOSED_PAGE_SIZE);
 	}
 
+end:
 	if (pblk_io_aligned(pblk, nr_secs))
 		rqd->is_seq = 1;
 
 #ifdef CONFIG_NVM_PBLK_DEBUG
 	atomic_long_add(nr_secs, &pblk->inflight_reads);
 #endif
+
+	return nr_secs;
 }
 
 
@@ -197,9 +198,7 @@ static void __pblk_end_io_read(struct pblk *pblk, struct nvm_rq *rqd,
 		pblk_log_read_err(pblk, rqd);
 
 	pblk_read_check_seq(pblk, rqd, r_ctx->lba);
-
-	if (int_bio)
-		bio_put(int_bio);
+	bio_put(int_bio);
 
 	if (put_line)
 		pblk_rq_to_line_put(pblk, rqd);
@@ -223,183 +222,13 @@ static void pblk_end_io_read(struct nvm_rq *rqd)
 	__pblk_end_io_read(pblk, rqd, true);
 }
 
-static void pblk_end_partial_read(struct nvm_rq *rqd)
-{
-	struct pblk *pblk = rqd->private;
-	struct pblk_g_ctx *r_ctx = nvm_rq_to_pdu(rqd);
-	struct pblk_pr_ctx *pr_ctx = r_ctx->private;
-	struct pblk_sec_meta *meta;
-	struct bio *new_bio = rqd->bio;
-	struct bio *bio = pr_ctx->orig_bio;
-	void *meta_list = rqd->meta_list;
-	unsigned long *read_bitmap = pr_ctx->bitmap;
-	struct bvec_iter orig_iter = BVEC_ITER_ALL_INIT;
-	struct bvec_iter new_iter = BVEC_ITER_ALL_INIT;
-	int nr_secs = pr_ctx->orig_nr_secs;
-	int nr_holes = nr_secs - bitmap_weight(read_bitmap, nr_secs);
-	void *src_p, *dst_p;
-	int bit, i;
-
-	if (unlikely(nr_holes == 1)) {
-		struct ppa_addr ppa;
-
-		ppa = rqd->ppa_addr;
-		rqd->ppa_list = pr_ctx->ppa_ptr;
-		rqd->dma_ppa_list = pr_ctx->dma_ppa_list;
-		rqd->ppa_list[0] = ppa;
-	}
-
-	for (i = 0; i < nr_secs; i++) {
-		meta = pblk_get_meta(pblk, meta_list, i);
-		pr_ctx->lba_list_media[i] = le64_to_cpu(meta->lba);
-		meta->lba = cpu_to_le64(pr_ctx->lba_list_mem[i]);
-	}
-
-	/* Fill the holes in the original bio */
-	i = 0;
-	for (bit = 0; bit < nr_secs; bit++) {
-		if (!test_bit(bit, read_bitmap)) {
-			struct bio_vec dst_bv, src_bv;
-			struct pblk_line *line;
-
-			line = pblk_ppa_to_line(pblk, rqd->ppa_list[i]);
-			kref_put(&line->ref, pblk_line_put);
-
-			meta = pblk_get_meta(pblk, meta_list, bit);
-			meta->lba = cpu_to_le64(pr_ctx->lba_list_media[i]);
-
-			dst_bv = bio_iter_iovec(bio, orig_iter);
-			src_bv = bio_iter_iovec(new_bio, new_iter);
-
-			src_p = kmap_atomic(src_bv.bv_page);
-			dst_p = kmap_atomic(dst_bv.bv_page);
-
-			memcpy(dst_p + dst_bv.bv_offset,
-				src_p + src_bv.bv_offset,
-				PBLK_EXPOSED_PAGE_SIZE);
-
-			kunmap_atomic(src_p);
-			kunmap_atomic(dst_p);
-
-			flush_dcache_page(dst_bv.bv_page);
-			mempool_free(src_bv.bv_page, &pblk->page_bio_pool);
-
-			bio_advance_iter(new_bio, &new_iter,
-					PBLK_EXPOSED_PAGE_SIZE);
-			i++;
-		}
-		bio_advance_iter(bio, &orig_iter, PBLK_EXPOSED_PAGE_SIZE);
-	}
-
-	bio_put(new_bio);
-	kfree(pr_ctx);
-
-	/* restore original request */
-	rqd->bio = NULL;
-	rqd->nr_ppas = nr_secs;
-
-	pblk_end_user_read(bio, rqd->error);
-	__pblk_end_io_read(pblk, rqd, false);
-}
-
-static int pblk_setup_partial_read(struct pblk *pblk, struct nvm_rq *rqd,
-			    unsigned int bio_init_idx,
-			    unsigned long *read_bitmap,
-			    int nr_holes)
-{
-	void *meta_list = rqd->meta_list;
-	struct pblk_g_ctx *r_ctx = nvm_rq_to_pdu(rqd);
-	struct pblk_pr_ctx *pr_ctx;
-	struct bio *new_bio, *bio = r_ctx->private;
-	int nr_secs = rqd->nr_ppas;
-	int i;
-
-	new_bio = bio_alloc(GFP_KERNEL, nr_holes);
-
-	if (pblk_bio_add_pages(pblk, new_bio, GFP_KERNEL, nr_holes))
-		goto fail_bio_put;
-
-	if (nr_holes != new_bio->bi_vcnt) {
-		WARN_ONCE(1, "pblk: malformed bio\n");
-		goto fail_free_pages;
-	}
-
-	pr_ctx = kzalloc(sizeof(struct pblk_pr_ctx), GFP_KERNEL);
-	if (!pr_ctx)
-		goto fail_free_pages;
-
-	for (i = 0; i < nr_secs; i++) {
-		struct pblk_sec_meta *meta = pblk_get_meta(pblk, meta_list, i);
-
-		pr_ctx->lba_list_mem[i] = le64_to_cpu(meta->lba);
-	}
-
-	new_bio->bi_iter.bi_sector = 0; /* internal bio */
-	bio_set_op_attrs(new_bio, REQ_OP_READ, 0);
-
-	rqd->bio = new_bio;
-	rqd->nr_ppas = nr_holes;
-
-	pr_ctx->orig_bio = bio;
-	bitmap_copy(pr_ctx->bitmap, read_bitmap, NVM_MAX_VLBA);
-	pr_ctx->bio_init_idx = bio_init_idx;
-	pr_ctx->orig_nr_secs = nr_secs;
-	r_ctx->private = pr_ctx;
-
-	if (unlikely(nr_holes == 1)) {
-		pr_ctx->ppa_ptr = rqd->ppa_list;
-		pr_ctx->dma_ppa_list = rqd->dma_ppa_list;
-		rqd->ppa_addr = rqd->ppa_list[0];
-	}
-	return 0;
-
-fail_free_pages:
-	pblk_bio_free_pages(pblk, new_bio, 0, new_bio->bi_vcnt);
-fail_bio_put:
-	bio_put(new_bio);
-
-	return -ENOMEM;
-}
-
-static int pblk_partial_read_bio(struct pblk *pblk, struct nvm_rq *rqd,
-				 unsigned int bio_init_idx,
-				 unsigned long *read_bitmap, int nr_secs)
-{
-	int nr_holes;
-	int ret;
-
-	nr_holes = nr_secs - bitmap_weight(read_bitmap, nr_secs);
-
-	if (pblk_setup_partial_read(pblk, rqd, bio_init_idx, read_bitmap,
-				    nr_holes))
-		return NVM_IO_ERR;
-
-	rqd->end_io = pblk_end_partial_read;
-
-	ret = pblk_submit_io(pblk, rqd);
-	if (ret) {
-		bio_put(rqd->bio);
-		pblk_err(pblk, "partial read IO submission failed\n");
-		goto err;
-	}
-
-	return NVM_IO_OK;
-
-err:
-	pblk_err(pblk, "failed to perform partial read\n");
-
-	/* Free allocated pages in new bio */
-	pblk_bio_free_pages(pblk, rqd->bio, 0, rqd->bio->bi_vcnt);
-	return NVM_IO_ERR;
-}
-
 static void pblk_read_rq(struct pblk *pblk, struct nvm_rq *rqd, struct bio *bio,
-			 sector_t lba, unsigned long *read_bitmap)
+			 sector_t lba, bool *from_cache)
 {
 	struct pblk_sec_meta *meta = pblk_get_meta(pblk, rqd->meta_list, 0);
 	struct ppa_addr ppa;
 
-	pblk_lookup_l2p_seq(pblk, &ppa, lba, 1);
+	pblk_lookup_l2p_seq(pblk, &ppa, lba, 1, from_cache);
 
 #ifdef CONFIG_NVM_PBLK_DEBUG
 	atomic_long_inc(&pblk->inflight_reads);
@@ -409,7 +238,6 @@ retry:
 	if (pblk_ppa_empty(ppa)) {
 		__le64 addr_empty = cpu_to_le64(ADDR_EMPTY);
 
-		WARN_ON(test_and_set_bit(0, read_bitmap));
 		meta->lba = addr_empty;
 		return;
 	}
@@ -418,12 +246,11 @@ retry:
 	 * write buffer to prevent retrieving overwritten data.
 	 */
 	if (pblk_addr_in_cache(ppa)) {
-		if (!pblk_read_from_cache(pblk, bio, lba, ppa, 0, 1)) {
-			pblk_lookup_l2p_seq(pblk, &ppa, lba, 1);
+		if (!pblk_read_from_cache(pblk, bio, lba, ppa)) {
+			pblk_lookup_l2p_seq(pblk, &ppa, lba, 1, from_cache);
 			goto retry;
 		}
 
-		WARN_ON(test_and_set_bit(0, read_bitmap));
 		meta->lba = cpu_to_le64(lba);
 
 #ifdef CONFIG_NVM_PBLK_DEBUG
@@ -440,17 +267,14 @@ void pblk_submit_read(struct pblk *pblk, struct bio *bio)
 	struct request_queue *q = dev->q;
 	sector_t blba = pblk_get_lba(bio);
 	unsigned int nr_secs = pblk_get_secs(bio);
+	bool from_cache;
 	struct pblk_g_ctx *r_ctx;
 	struct nvm_rq *rqd;
-	struct bio *int_bio;
-	unsigned int bio_init_idx;
-	DECLARE_BITMAP(read_bitmap, NVM_MAX_VLBA);
+	struct bio *int_bio, *split_bio;
 
 	generic_start_io_acct(q, REQ_OP_READ, bio_sectors(bio),
 			      &pblk->disk->part0);
 
-	bitmap_zero(read_bitmap, nr_secs);
-
 	rqd = pblk_alloc_rqd(pblk, PBLK_READ);
 
 	rqd->opcode = NVM_OP_PREAD;
@@ -462,11 +286,6 @@ void pblk_submit_read(struct pblk *pblk, struct bio *bio)
 	r_ctx->start_time = jiffies;
 	r_ctx->lba = blba;
 
-	/* Save the index for this bio's start. This is needed in case
-	 * we need to fill a partial read.
-	 */
-	bio_init_idx = pblk_get_bi_idx(bio);
-
 	if (pblk_alloc_rqd_meta(pblk, rqd)) {
 		bio_io_error(bio);
 		pblk_free_rqd(pblk, rqd, PBLK_READ);
@@ -475,46 +294,58 @@ void pblk_submit_read(struct pblk *pblk, struct bio *bio)
 
 	/* Clone read bio to deal internally with:
 	 * -read errors when reading from drive
-	 * -bio_advance() calls during l2p lookup and cache reads
+	 * -bio_advance() calls during cache reads
 	 */
 	int_bio = bio_clone_fast(bio, GFP_KERNEL, &pblk_bio_set);
 
 	if (nr_secs > 1)
-		pblk_read_ppalist_rq(pblk, rqd, bio, blba, read_bitmap);
+		nr_secs = pblk_read_ppalist_rq(pblk, rqd, int_bio, blba,
+						&from_cache);
 	else
-		pblk_read_rq(pblk, rqd, bio, blba, read_bitmap);
+		pblk_read_rq(pblk, rqd, int_bio, blba, &from_cache);
 
+split_retry:
 	r_ctx->private = bio; /* original bio */
 	rqd->bio = int_bio; /* internal bio */
 
-	if (bitmap_full(read_bitmap, nr_secs)) {
+	if (from_cache && nr_secs == rqd->nr_ppas) {
+		/* All data was read from cache, we can complete the IO. */
 		pblk_end_user_read(bio, 0);
 		atomic_inc(&pblk->inflight_io);
 		__pblk_end_io_read(pblk, rqd, false);
-		return;
-	}
-
-	if (!bitmap_empty(read_bitmap, rqd->nr_ppas)) {
+	} else if (nr_secs != rqd->nr_ppas) {
 		/* The read bio request could be partially filled by the write
 		 * buffer, but there are some holes that need to be read from
-		 * the drive.
+		 * the drive. In order to handle this, we will use block layer
+		 * mechanism to split this request in to smaller ones and make
+		 * a chain of it.
 		 */
-		bio_put(int_bio);
-		rqd->bio = NULL;
-		if (pblk_partial_read_bio(pblk, rqd, bio_init_idx, read_bitmap,
-					    nr_secs)) {
-			pblk_err(pblk, "read IO submission failed\n");
-			bio_io_error(bio);
-			__pblk_end_io_read(pblk, rqd, false);
-		}
-		return;
-	}
+		split_bio = bio_split(bio, nr_secs * NR_PHY_IN_LOG, GFP_KERNEL,
+					&pblk_bio_set);
+		bio_chain(split_bio, bio);
+		generic_make_request(bio);
+
+		/* New bio contains first N sectors of the previous one, so
+		 * we can continue to use existing rqd, but we need to shrink
+		 * the number of PPAs in it. New bio is also guaranteed that
+		 * it contains only either data from cache or from drive, newer
+		 * mix of them.
+		 */
+		bio = split_bio;
+		rqd->nr_ppas = nr_secs;
+		if (rqd->nr_ppas == 1)
+			rqd->ppa_addr = rqd->ppa_list[0];
 
-	/* All sectors are to be read from the device */
-	if (pblk_submit_io(pblk, rqd)) {
-		pblk_err(pblk, "read IO submission failed\n");
-		bio_io_error(bio);
-		__pblk_end_io_read(pblk, rqd, false);
+		/* Recreate int_bio - existing might have some needed internal
+		 * fields modified already.
+		 */
+		bio_put(int_bio);
+		int_bio = bio_clone_fast(bio, GFP_KERNEL, &pblk_bio_set);
+		goto split_retry;
+	} else if (pblk_submit_io(pblk, rqd)) {
+		/* Submitting IO to drive failed, let's report an error */
+		rqd->error = -ENODEV;
+		pblk_end_io_read(rqd);
 	}
 }