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authorMike Snitzer <snitzer@redhat.com>2009-06-22 10:12:34 +0100
committerAlasdair G Kergon <agk@redhat.com>2009-06-22 10:12:34 +0100
commit754c5fc7ebb417b23601a6222a6005cc2e7f2913 (patch)
tree6c31b055fc26ec541d67fc1123ebaa4b7a8eae7a /Documentation/device-mapper
parent18d8594dd93a1ae2fafd591ec026e87d743292bf (diff)
dm: calculate queue limits during resume not load
Currently, device-mapper maintains a separate instance of 'struct queue_limits' for each table of each device. When the configuration of a device is to be changed, first its table is loaded and this structure is populated, then the device is 'resumed' and the calculated queue_limits are applied. This places restrictions on how userspace may process related devices, where it is often advantageous to 'load' tables for several devices at once before 'resuming' them together. As the new queue_limits only take effect after the 'resume', if they are changing and one device uses another, the latter must be 'resumed' before the former may be 'loaded'. This patch moves the calculation of these queue_limits out of the 'load' operation into 'resume'. Since we are no longer pre-calculating this struct, we no longer need to maintain copies within our dm structs. dm_set_device_limits() now passes the 'start' of the device's data area (aka pe_start) as the 'offset' to blk_stack_limits(). init_valid_queue_limits() is replaced by blk_set_default_limits(). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: martin.petersen@oracle.com Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'Documentation/device-mapper')
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