linux-kernel - [PATCH 09/13] lightnvm/pblk-read: use bio_clone

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Date:   Tue, 02 May 2017 13:42:25 +1000
From:   NeilBrown <neilb@...e.com>
To:     Jens Axboe <axboe@...nel.dk>
Cc:     Javier Gonzalez <jg@...htnvm.io>
Subject: [PATCH 09/13] lightnvm/pblk-read: use bio_clone_fast()

pblk_submit_read() uses bio_clone_bioset() but doesn't change the
io_vec, so bio_clone_fast() is a better choice.

It also uses fs_bio_set which is intended for filesystems.  Using it
in a device driver can deadlock.
So allocate a new bioset, and and use bio_clone_fast().

Signed-off-by: NeilBrown <neilb@...e.com>
---
 drivers/lightnvm/pblk-init.c |   12 +++++++++++-
 drivers/lightnvm/pblk-read.c |    2 +-
 drivers/lightnvm/pblk.h      |    1 +
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
index b3fec8ec55b8..aaefbccce30e 100644
--- a/drivers/lightnvm/pblk-init.c
+++ b/drivers/lightnvm/pblk-init.c
@@ -23,6 +23,7 @@
 static struct kmem_cache *pblk_blk_ws_cache, *pblk_rec_cache, *pblk_r_rq_cache,
 					*pblk_w_rq_cache, *pblk_line_meta_cache;
 static DECLARE_RWSEM(pblk_lock);
+struct bio_set *pblk_bio_set;
 
 static int pblk_rw_io(struct request_queue *q, struct pblk *pblk,
 			  struct bio *bio)
@@ -946,11 +947,20 @@ static struct nvm_tgt_type tt_pblk = {
 
 static int __init pblk_module_init(void)
 {
-	return nvm_register_tgt_type(&tt_pblk);
+	int ret;
+
+	pblk_bio_set = bioset_create(BIO_POOL_SIZE, 0, 0);
+	if (!pblk_bio_set)
+		return -ENOMEM;
+	ret = nvm_register_tgt_type(&tt_pblk);
+	if (ret)
+		bioset_free(pblk_bio_set);
+	return ret;
 }
 
 static void pblk_module_exit(void)
 {
+	bioset_free(pblk_bio_set);
 	nvm_unregister_tgt_type(&tt_pblk);
 }
 
diff --git a/drivers/lightnvm/pblk-read.c b/drivers/lightnvm/pblk-read.c
index 4a12f14d78c6..8ee0c50a7a71 100644
--- a/drivers/lightnvm/pblk-read.c
+++ b/drivers/lightnvm/pblk-read.c
@@ -342,7 +342,7 @@ int pblk_submit_read(struct pblk *pblk, struct bio *bio)
 		struct pblk_r_ctx *r_ctx = nvm_rq_to_pdu(rqd);
 
 		/* Clone read bio to deal with read errors internally */
-		int_bio = bio_clone_bioset(bio, GFP_KERNEL, fs_bio_set);
+		int_bio = bio_clone_fast(bio, GFP_KERNEL, pblk_bio_set);
 		if (!int_bio) {
 			pr_err("pblk: could not clone read bio\n");
 			return NVM_IO_ERR;
diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
index 99f3186b5288..95b665f23925 100644
--- a/drivers/lightnvm/pblk.h
+++ b/drivers/lightnvm/pblk.h
@@ -702,6 +702,7 @@ void pblk_write_should_kick(struct pblk *pblk);
 /*
  * pblk read path
  */
+extern struct bio_set *pblk_bio_set;
 int pblk_submit_read(struct pblk *pblk, struct bio *bio);
 int pblk_submit_read_gc(struct pblk *pblk, u64 *lba_list, void *data,
 			unsigned int nr_secs, unsigned int *secs_to_gc,