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From: Li Chen <me@linux.beauty>
To: Pankaj Gupta <pankaj.gupta.linux@gmail.com>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Alison Schofield <alison.schofield@intel.com>,
	virtualization@lists.linux.dev, nvdimm@lists.linux.dev
Cc: linux-kernel@vger.kernel.org, Li Chen <me@linux.beauty>
Subject: [PATCH v7 03/12] nvdimm: pmem: guard data loop for dataless bios
Date: Tue, 30 Jun 2026 17:23:28 +0800	[thread overview]
Message-ID: <20260630092338.2094628-4-me@linux.beauty> (raw)
In-Reply-To: <20260630092338.2094628-1-me@linux.beauty>

pmem_submit_bio() handles flush-only bios before and after the data
loop. Keep dataless bios out of bio_for_each_segment() so the data path
only walks bios that actually carry bvec data.

Signed-off-by: Li Chen <me@linux.beauty>
---
Changes in v6:
- New patch.

 drivers/nvdimm/pmem.c | 36 +++++++++++++++++++++---------------
 1 file changed, 21 insertions(+), 15 deletions(-)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 05d3de33e2706..82ee1ddb3a445 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -217,23 +217,29 @@ static void pmem_submit_bio(struct bio *bio)
 		}
 	}
 
-	do_acct = blk_queue_io_stat(bio->bi_bdev->bd_disk->queue);
-	if (do_acct)
-		start = bio_start_io_acct(bio);
-	bio_for_each_segment(bvec, bio, iter) {
-		if (op_is_write(bio_op(bio)))
-			rc = pmem_do_write(pmem, bvec.bv_page, bvec.bv_offset,
-				iter.bi_sector, bvec.bv_len);
-		else
-			rc = pmem_do_read(pmem, bvec.bv_page, bvec.bv_offset,
-				iter.bi_sector, bvec.bv_len);
-		if (rc) {
-			bio->bi_status = rc;
-			break;
+	if (bio_has_data(bio)) {
+		do_acct = blk_queue_io_stat(bio->bi_bdev->bd_disk->queue);
+		if (do_acct)
+			start = bio_start_io_acct(bio);
+		bio_for_each_segment(bvec, bio, iter) {
+			if (op_is_write(bio_op(bio)))
+				rc = pmem_do_write(pmem, bvec.bv_page,
+						   bvec.bv_offset,
+						   iter.bi_sector,
+						   bvec.bv_len);
+			else
+				rc = pmem_do_read(pmem, bvec.bv_page,
+						  bvec.bv_offset,
+						  iter.bi_sector,
+						  bvec.bv_len);
+			if (rc) {
+				bio->bi_status = rc;
+				break;
+			}
 		}
+		if (do_acct)
+			bio_end_io_acct(bio, start);
 	}
-	if (do_acct)
-		bio_end_io_acct(bio, start);
 
 	if ((bio->bi_opf & REQ_FUA) && !bio->bi_status)
 		ret = nvdimm_flush(nd_region, bio);
-- 
2.52.0

  parent reply	other threads:[~2026-06-30  9:24 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-30  9:23 [PATCH v7 00/12] nvdimm: virtio_pmem: fix flush/request failure paths Li Chen
2026-06-30  9:23 ` [PATCH v7 01/12] nvdimm: preserve flush callback -ENOMEM Li Chen
2026-06-30  9:23 ` [PATCH v7 02/12] nvdimm: pmem: keep PREFLUSH before data writes Li Chen
2026-06-30  9:23 ` Li Chen [this message]
2026-06-30  9:23 ` [PATCH v7 04/12] nvdimm: virtio_pmem: stop allocating child flush bio Li Chen
2026-06-30 10:28   ` sashiko-bot
2026-06-30  9:23 ` [PATCH v7 05/12] nvdimm: virtio_pmem: use GFP_NOIO for flush requests Li Chen
2026-06-30 10:42   ` sashiko-bot
2026-06-30  9:23 ` [PATCH v7 06/12] nvdimm: virtio_pmem: always wake -ENOSPC waiters Li Chen
2026-06-30  9:23 ` [PATCH v7 07/12] nvdimm: virtio_pmem: use READ_ONCE()/WRITE_ONCE() for wait flags Li Chen
2026-06-30  9:23 ` [PATCH v7 08/12] nvdimm: virtio_pmem: refcount requests for token lifetime Li Chen
2026-06-30  9:23 ` [PATCH v7 09/12] nvdimm: virtio_pmem: publish done with release/acquire Li Chen
2026-06-30  9:23 ` [PATCH v7 10/12] nvdimm: virtio_pmem: isolate DMA request buffers Li Chen
2026-06-30  9:23 ` [PATCH v7 11/12] nvdimm: virtio_pmem: converge broken virtqueue to -EIO Li Chen
2026-06-30 11:50   ` sashiko-bot
2026-06-30  9:23 ` [PATCH v7 12/12] nvdimm: virtio_pmem: drain requests in freeze Li Chen
2026-06-30  9:47 ` [PATCH v7 00/12] nvdimm: virtio_pmem: fix flush/request failure paths Pankaj Gupta

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