block: add partition attribute for partition number (0fc71e3d) · Commits · 戴 / test

With extended devt, finding out the partition number becomes a bit more challenging as subtracting the minor number from that of the parent device doesn't work anymore. The only thing left is parsing the partition name which is brittle and not exactly universal (some have '-' between the device name and partition number while others don't). This patch introduced partition attribute which contains the partition number of the device. This should make finding partitions and its index easier. This problem and solution were suggested by H. Peter Anvin. Signed-off-by:

Tejun Heo <tj@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Signed-off-by:

Jens Axboe <jens.axboe@oracle.com>

fs/partitions/check.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -195,6 +195,14 @@ check_partition(struct gendisk hd, struct block_device bdev)
		return ERR_PTR(res);
		}

		static ssize_t part_partition_show(struct device *dev,
		struct device_attribute attr, char buf)
		{
		struct hd_struct *p = dev_to_part(dev);

		return sprintf(buf, "%d\n", p->partno);
		}

		static ssize_t part_start_show(struct device *dev,
		struct device_attribute attr, char buf)
		{
		@@ -260,6 +268,7 @@ ssize_t part_fail_store(struct device *dev,
		}
		#endif

		static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
		static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
		static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
		static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
		@@ -269,6 +278,7 @@ static struct device_attribute dev_attr_fail =
		#endif

		static struct attribute *part_attrs[] = {
		&dev_attr_partition.attr,
		&dev_attr_start.attr,
		&dev_attr_size.attr,
		&dev_attr_stat.attr,

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