[Devel] [vzlin-dev] [PATCH vz7] md: propagate QUEUE_FLAG_SG_GAPS

Maxim Patlasov mpatlasov at virtuozzo.com
Thu Dec 8 21:35:26 PST 2016


Mainline is not affected. (they re-worked the whole engine completely so 
the problem vanished auto-magically)


On 12/08/2016 09:21 PM, Vasily Averin wrote:
> Maxim,
> will you sent this to mainline too ?
>
> thank you,
> 	Vasily Averin
>
> On 12/09/2016 08:17 AM, Maxim Patlasov wrote:
>> NVMe disk driver disables sg gaps by setting the flag in its queue.
>> md-raids must propagate the flag to its queue as well. Otherwise, an upper
>> user will get OK from bio_add_page() even if a gap exists, and that bio
>> with a gap will crash NVMe driver who doesn't expect gaps.
>> (see bvec_gap_to_prev for the definotion of gap)
>>
>> https://jira.sw.ru/browse/PSBM-56838
>>
>> Signed-off-by: Maxim Patlasov <mpatlasov at virtuozzo.com>
>> ---
>>   drivers/md/linear.c    |    9 +++++++++
>>   drivers/md/raid0.c     |    8 ++++++++
>>   drivers/md/raid1.c     |   11 +++++++++++
>>   drivers/md/raid10.c    |   12 ++++++++++++
>>   drivers/md/raid5.c     |   10 ++++++++++
>>   include/linux/blkdev.h |    1 +
>>   6 files changed, 51 insertions(+)
>>
>> diff --git a/drivers/md/linear.c b/drivers/md/linear.c
>> index 3310b59..e57b8ff 100644
>> --- a/drivers/md/linear.c
>> +++ b/drivers/md/linear.c
>> @@ -128,6 +128,7 @@ static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks)
>>   	struct md_rdev *rdev;
>>   	int i, cnt;
>>   	bool discard_supported = false;
>> +	bool sg_gaps_disabled = false;
>>   
>>   	conf = kzalloc (sizeof (*conf) + raid_disks*sizeof(struct dev_info),
>>   			GFP_KERNEL);
>> @@ -163,6 +164,9 @@ static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks)
>>   
>>   		if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
>>   			discard_supported = true;
>> +
>> +		if (blk_queue_sg_gaps(bdev_get_queue(rdev->bdev)))
>> +			sg_gaps_disabled = true;
>>   	}
>>   	if (cnt != raid_disks) {
>>   		printk(KERN_ERR "md/linear:%s: not enough drives present. Aborting!\n",
>> @@ -175,6 +179,11 @@ static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks)
>>   	else
>>   		queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
>>   
>> +	if (!sg_gaps_disabled)
>> +		queue_flag_clear_unlocked(QUEUE_FLAG_SG_GAPS, mddev->queue);
>> +	else
>> +		queue_flag_set_unlocked(QUEUE_FLAG_SG_GAPS, mddev->queue);
>> +
>>   	/*
>>   	 * Here we calculate the device offsets.
>>   	 */
>> diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
>> index 100ef23..2b77d0f 100644
>> --- a/drivers/md/raid0.c
>> +++ b/drivers/md/raid0.c
>> @@ -435,6 +435,7 @@ static int raid0_run(struct mddev *mddev)
>>   	if (mddev->queue) {
>>   		struct md_rdev *rdev;
>>   		bool discard_supported = false;
>> +		bool sg_gaps_disabled = false;
>>   
>>   		blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
>>   		blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors);
>> @@ -449,6 +450,8 @@ static int raid0_run(struct mddev *mddev)
>>   					  rdev->data_offset << 9);
>>   			if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
>>   				discard_supported = true;
>> +			if (blk_queue_sg_gaps(bdev_get_queue(rdev->bdev)))
>> +				sg_gaps_disabled = true;
>>   		}
>>   
>>   		/* Unfortunately, some devices have awful discard performance,
>> @@ -470,6 +473,11 @@ static int raid0_run(struct mddev *mddev)
>>   			queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
>>   		else
>>   			queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
>> +
>> +		if (!sg_gaps_disabled)
>> +			queue_flag_clear_unlocked(QUEUE_FLAG_SG_GAPS, mddev->queue);
>> +		else
>> +			queue_flag_set_unlocked(QUEUE_FLAG_SG_GAPS, mddev->queue);
>>   	}
>>   
>>   	/* calculate array device size */
>> diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
>> index b45b64c..a1763b5 100644
>> --- a/drivers/md/raid1.c
>> +++ b/drivers/md/raid1.c
>> @@ -1663,6 +1663,8 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
>>   	md_integrity_add_rdev(rdev, mddev);
>>   	if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
>>   		queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
>> +	if (mddev->queue && blk_queue_sg_gaps(bdev_get_queue(rdev->bdev)))
>> +		queue_flag_set_unlocked(QUEUE_FLAG_SG_GAPS, mddev->queue);
>>   	print_conf(conf);
>>   	return err;
>>   }
>> @@ -2905,6 +2907,7 @@ static int run(struct mddev *mddev)
>>   	struct md_rdev *rdev;
>>   	int ret;
>>   	bool discard_supported = false;
>> +	bool sg_gaps_disabled = false;
>>   
>>   	if (mddev->level != 1) {
>>   		printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n",
>> @@ -2939,6 +2942,8 @@ static int run(struct mddev *mddev)
>>   				  rdev->data_offset << 9);
>>   		if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
>>   			discard_supported = true;
>> +		if (blk_queue_sg_gaps(bdev_get_queue(rdev->bdev)))
>> +			sg_gaps_disabled = true;
>>   	}
>>   
>>   	mddev->degraded = 0;
>> @@ -2976,6 +2981,12 @@ static int run(struct mddev *mddev)
>>   		else
>>   			queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
>>   						  mddev->queue);
>> +		if (sg_gaps_disabled)
>> +			queue_flag_set_unlocked(QUEUE_FLAG_SG_GAPS,
>> +						mddev->queue);
>> +		else
>> +			queue_flag_clear_unlocked(QUEUE_FLAG_SG_GAPS,
>> +						  mddev->queue);
>>   	}
>>   
>>   	ret =  md_integrity_register(mddev);
>> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
>> index f0c7f3b..52f8d73 100644
>> --- a/drivers/md/raid10.c
>> +++ b/drivers/md/raid10.c
>> @@ -1865,6 +1865,8 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
>>   	md_integrity_add_rdev(rdev, mddev);
>>   	if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
>>   		queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
>> +	if (mddev->queue && blk_queue_sg_gaps(bdev_get_queue(rdev->bdev)))
>> +		queue_flag_set_unlocked(QUEUE_FLAG_SG_GAPS, mddev->queue);
>>   
>>   	print_conf(conf);
>>   	return err;
>> @@ -3650,6 +3652,7 @@ static int run(struct mddev *mddev)
>>   	sector_t min_offset_diff = 0;
>>   	int first = 1;
>>   	bool discard_supported = false;
>> +	bool sg_gaps_disabled = false;
>>   
>>   	if (mddev->private == NULL) {
>>   		conf = setup_conf(mddev);
>> @@ -3717,6 +3720,9 @@ static int run(struct mddev *mddev)
>>   
>>   		if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
>>   			discard_supported = true;
>> +
>> +		if (blk_queue_sg_gaps(bdev_get_queue(rdev->bdev)))
>> +			sg_gaps_disabled = true;
>>   	}
>>   
>>   	if (mddev->queue) {
>> @@ -3726,6 +3732,12 @@ static int run(struct mddev *mddev)
>>   		else
>>   			queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
>>   						  mddev->queue);
>> +		if (sg_gaps_disabled)
>> +			queue_flag_set_unlocked(QUEUE_FLAG_SG_GAPS,
>> +						mddev->queue);
>> +		else
>> +			queue_flag_clear_unlocked(QUEUE_FLAG_SG_GAPS,
>> +						  mddev->queue);
>>   	}
>>   	/* need to check that every block has at least one working mirror */
>>   	if (!enough(conf, -1)) {
>> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
>> index 50902ad1..862b86f 100644
>> --- a/drivers/md/raid5.c
>> +++ b/drivers/md/raid5.c
>> @@ -6814,6 +6814,7 @@ static int run(struct mddev *mddev)
>>   	if (mddev->queue) {
>>   		int chunk_size;
>>   		bool discard_supported = true;
>> +		bool sg_gaps_disabled = false;
>>   		/* read-ahead size must cover two whole stripes, which
>>   		 * is 2 * (datadisks) * chunksize where 'n' is the
>>   		 * number of raid devices
>> @@ -6878,6 +6879,8 @@ static int run(struct mddev *mddev)
>>   				}
>>   				discard_supported = false;
>>   			}
>> +			if (blk_queue_sg_gaps(bdev_get_queue(rdev->bdev)))
>> +				sg_gaps_disabled = true;
>>   		}
>>   
>>   		if (discard_supported &&
>> @@ -6888,6 +6891,13 @@ static int run(struct mddev *mddev)
>>   		else
>>   			queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
>>   						mddev->queue);
>> +
>> +		if (sg_gaps_disabled)
>> +			queue_flag_set_unlocked(QUEUE_FLAG_SG_GAPS,
>> +						mddev->queue);
>> +		else
>> +			queue_flag_clear_unlocked(QUEUE_FLAG_SG_GAPS,
>> +						mddev->queue);
>>   	}
>>   
>>   	return 0;
>> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
>> index 8b400c6..e3752b1 100644
>> --- a/include/linux/blkdev.h
>> +++ b/include/linux/blkdev.h
>> @@ -639,6 +639,7 @@ static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
>>   #define blk_queue_discard(q)	test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
>>   #define blk_queue_secdiscard(q)	(blk_queue_discard(q) && \
>>   	test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
>> +#define blk_queue_sg_gaps(q)	test_bit(QUEUE_FLAG_SG_GAPS, &(q)->queue_flags)
>>   
>>   #define blk_noretry_request(rq) \
>>   	((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
>>
>>



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