unimore/kernel-hacking-2024-linux-steffo
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block: only define 'nr_sects_seq' in hd_part for 32bit SMP

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The seqcount of 'nr_sects_seq' is only needed in case of 32bit SMP,
so define it just for 32bit SMP.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Cc: Yufen Yu <yuyufen@huawei.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hou Tao <houtao1@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei 2020-05-08 16:17:56 +08:00 committed by Jens Axboe
parent b7d6c30333
commit 07c4e1e834
3 changed files with 11 additions and 2 deletions
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2
block/genhd.c
View file

@ -1731,7 +1731,7 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
* TODO: Ideally set_capacity() and get_capacity() should be
* converted to make use of bd_mutex and sequence counters.
*/
seqcount_init(&disk->part0.nr_sects_seq);
hd_sects_seq_init(&disk->part0);
if (hd_ref_init(&disk->part0)) {
hd_free_part(&disk->part0);
kfree(disk);

2
block/partitions/core.c
View file

@ -392,7 +392,7 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
goto out_free;
}
seqcount_init(&p->nr_sects_seq);
hd_sects_seq_init(p);
pdev = part_to_dev(p);
p->start_sect = start;

9
include/linux/genhd.h
View file

@ -68,7 +68,9 @@ struct hd_struct {
* can be non-atomic on 32bit machines with 64bit sector_t.
*/
sector_t nr_sects;
#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
seqcount_t nr_sects_seq;
#endif
sector_t alignment_offset;
unsigned int discard_alignment;
struct device __dev;
@ -274,6 +276,13 @@ static inline void disk_put_part(struct hd_struct *part)
put_device(part_to_dev(part));
}
static inline void hd_sects_seq_init(struct hd_struct *p)
{
#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
seqcount_init(&p->nr_sects_seq);
#endif
}
/*
* Smarter partition iterator without context limits.
*/