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[dm-devel] dm_calculate_queue_limits and default values



Hi,

I'm a newbie on dm and all this stuff, but I'm wondering why "max_segments" of all dm's queue is always 128 (cat /sys/block/dm-*/queue/max_segments), even if all devices used in the dm have another value (cat /sys/devices/pci0000:00/0000:00:1f.2/host0/scsi_host/host0/sg_tablesize : 168).

I looked over the source code of dm_calculate_queue_limits, and saw that limits of all devices are combined with default limits (blk_set_default_limits(limits);). But, the value used is always the min_not_zero, so always 128, the default value.

As I understand, even if all devices have big limits, default values will be used.
Is my understanding wrong or there is a bug ?

Thank you to explain me the dm operation.

Regards

Benoit Welterlen
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