lightnvm: pblk: IO path reorganization

This patch is made in order to prepare read path for new approach to
partial read handling, which is simpler in compare with previous one.

The most important change is to move the handling of completed and
failed bio from the pblk_make_rq() to particular read and write
functions. This is needed, since after partial read path changes,
sometimes completed/failed bio will be different from original one, so
we cannot do this any longer in pblk_make_rq().

Other changes are small read path refactor in order to reduce the size
of the following patch with partial read changes.

Generally the goal of this patch is not to change the functionality,
but just to prepare the code for the following changes.

Signed-off-by: Igor Konopko <igor.j.konopko@intel.com>
Reviewed-by: Javier González <javier@javigon.com>
Signed-off-by: Matias Bjørling <mb@lightnvm.io>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 38 insertions, 45 deletions

diff --git a/drivers/lightnvm/pblk-read.c b/drivers/lightnvm/pblk-read.c
index 27f8a76d8bd8..f5f155d540e2 100644
--- a/drivers/lightnvm/pblk-read.c
+++ b/drivers/lightnvm/pblk-read.c
@@ -179,7 +179,8 @@ static void pblk_end_user_read(struct bio *bio, int error)
 {
 	if (error && error != NVM_RSP_WARN_HIGHECC)
 		bio_io_error(bio);
-	bio_endio(bio);
+	else
+		bio_endio(bio);
 }
 
 static void __pblk_end_io_read(struct pblk *pblk, struct nvm_rq *rqd,
@@ -389,7 +390,6 @@ err:
 
 	/* Free allocated pages in new bio */
 	pblk_bio_free_pages(pblk, rqd->bio, 0, rqd->bio->bi_vcnt);
-	__pblk_end_io_read(pblk, rqd, false);
 	return NVM_IO_ERR;
 }
 
@@ -434,7 +434,7 @@ retry:
 	}
 }
 
-int pblk_submit_read(struct pblk *pblk, struct bio *bio)
+void pblk_submit_read(struct pblk *pblk, struct bio *bio)
 {
 	struct nvm_tgt_dev *dev = pblk->dev;
 	struct request_queue *q = dev->q;
@@ -442,9 +442,9 @@ int pblk_submit_read(struct pblk *pblk, struct bio *bio)
 	unsigned int nr_secs = pblk_get_secs(bio);
 	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);
-	int ret = NVM_IO_ERR;
 
 	generic_start_io_acct(q, REQ_OP_READ, bio_sectors(bio),
 			      &pblk->disk->part0);
@@ -455,74 +455,67 @@ int pblk_submit_read(struct pblk *pblk, struct bio *bio)
 
 	rqd->opcode = NVM_OP_PREAD;
 	rqd->nr_ppas = nr_secs;
-	rqd->bio = NULL; /* cloned bio if needed */
 	rqd->private = pblk;
 	rqd->end_io = pblk_end_io_read;
 
 	r_ctx = nvm_rq_to_pdu(rqd);
 	r_ctx->start_time = jiffies;
 	r_ctx->lba = blba;
-	r_ctx->private = bio; /* original bio */
 
 	/* 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))
-		goto fail_rqd_free;
+	if (pblk_alloc_rqd_meta(pblk, rqd)) {
+		bio_io_error(bio);
+		pblk_free_rqd(pblk, rqd, PBLK_READ);
+		return;
+	}
+
+	/* Clone read bio to deal internally with:
+	 * -read errors when reading from drive
+	 * -bio_advance() calls during l2p lookup and 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);
 	else
 		pblk_read_rq(pblk, rqd, bio, blba, read_bitmap);
 
+	r_ctx->private = bio; /* original bio */
+	rqd->bio = int_bio; /* internal bio */
+
 	if (bitmap_full(read_bitmap, nr_secs)) {
+		pblk_end_user_read(bio, 0);
 		atomic_inc(&pblk->inflight_io);
 		__pblk_end_io_read(pblk, rqd, false);
-		return NVM_IO_DONE;
+		return;
 	}
 
-	/* All sectors are to be read from the device */
-	if (bitmap_empty(read_bitmap, rqd->nr_ppas)) {
-		struct bio *int_bio = NULL;
-
-		/* Clone read bio to deal with read errors internally */
-		int_bio = bio_clone_fast(bio, GFP_KERNEL, &pblk_bio_set);
-		if (!int_bio) {
-			pblk_err(pblk, "could not clone read bio\n");
-			goto fail_end_io;
-		}
-
-		rqd->bio = int_bio;
-
-		if (pblk_submit_io(pblk, rqd)) {
+	if (!bitmap_empty(read_bitmap, 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.
+		 */
+		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");
-			ret = NVM_IO_ERR;
-			goto fail_end_io;
+			bio_io_error(bio);
+			__pblk_end_io_read(pblk, rqd, false);
 		}
-
-		return NVM_IO_OK;
+		return;
 	}
 
-	/* 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.
-	 */
-	ret = pblk_partial_read_bio(pblk, rqd, bio_init_idx, read_bitmap,
-				    nr_secs);
-	if (ret)
-		goto fail_meta_free;
-
-	return NVM_IO_OK;
-
-fail_meta_free:
-	nvm_dev_dma_free(dev->parent, rqd->meta_list, rqd->dma_meta_list);
-fail_rqd_free:
-	pblk_free_rqd(pblk, rqd, PBLK_READ);
-	return ret;
-fail_end_io:
-	__pblk_end_io_read(pblk, rqd, false);
-	return ret;
+	/* 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);
+	}
 }
 
 static int read_ppalist_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,