linux-kernel - [PATCH 1/2] block: move partitions check code into single helper

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Date:   Fri,  5 Feb 2021 10:17:07 +0800
From:   Ming Lei <ming.lei@...hat.com>
To:     Jens Axboe <axboe@...nel.dk>
Cc:     Christoph Hellwig <hch@....de>, linux-block@...r.kernel.org,
        linux-kernel@...r.kernel.org, Ming Lei <ming.lei@...hat.com>,
        "Ewan D . Milne" <emilne@...hat.com>
Subject: [PATCH 1/2] block: move partitions check code into single helper

No functional change, make code more readable, and prepare for
supporting safe re-read partitions.

Cc: Ewan D. Milne <emilne@...hat.com>
Signed-off-by: Ming Lei <ming.lei@...hat.com>
---
 block/partitions/core.c | 51 ++++++++++++++++++++++++++++++-----------
 1 file changed, 37 insertions(+), 14 deletions(-)

diff --git a/block/partitions/core.c b/block/partitions/core.c
index b1cdf88f96e2..154013ea8623 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -599,17 +599,15 @@ static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev,
 	return true;
 }
 
-int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
+static int blk_check_partitions(struct gendisk *disk,
+		struct block_device *bdev, struct parsed_partitions **s)
 {
-	struct parsed_partitions *state;
-	int ret = -EAGAIN, p;
-
-	if (!disk_part_scan_enabled(disk))
-		return 0;
+	int ret = -EAGAIN;
+	struct parsed_partitions *state = check_partition(disk, bdev);
 
-	state = check_partition(disk, bdev);
 	if (!state)
-		return 0;
+		goto out;
+
 	if (IS_ERR(state)) {
 		/*
 		 * I/O error reading the partition table.  If we tried to read
@@ -647,15 +645,40 @@ int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
 			goto out_free_state;
 	}
 
+out:
+	*s = state;
+	return 0;
+
+out_free_state:
+	free_partitions(state);
+	*s = NULL;
+	return ret;
+}
+
+int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
+{
+	struct parsed_partitions *state;
+	int ret, p;
+
+	if (!disk_part_scan_enabled(disk))
+		return 0;
+
+	ret = blk_check_partitions(disk, bdev, &state);
+	if (ret != 0)
+		return ret;
+
+	if (!state)
+		return 0;
+
 	/* tell userspace that the media / partition table may have changed */
 	kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
 
-	for (p = 1; p < state->limit; p++)
-		if (!blk_add_partition(disk, bdev, state, p))
-			goto out_free_state;
-
-	ret = 0;
-out_free_state:
+	for (p = 1; p < state->limit; p++) {
+		if (!blk_add_partition(disk, bdev, state, p)) {
+			ret = -EAGAIN;
+			break;
+		}
+	}
 	free_partitions(state);
 	return ret;
 }
-- 
2.29.2