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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 /drivers/md/dm.h
parent18d8594dd93a1ae2fafd591ec026e87d743292bf (diff)
downloadop-kernel-dev-754c5fc7ebb417b23601a6222a6005cc2e7f2913.zip
op-kernel-dev-754c5fc7ebb417b23601a6222a6005cc2e7f2913.tar.gz
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 'drivers/md/dm.h')
-rw-r--r--drivers/md/dm.h5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index b5935c6..604e85c 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -41,7 +41,10 @@ void dm_table_event_callback(struct dm_table *t,
void (*fn)(void *), void *context);
struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index);
struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector);
-void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q);
+int dm_calculate_queue_limits(struct dm_table *table,
+ struct queue_limits *limits);
+void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
+ struct queue_limits *limits);
struct list_head *dm_table_get_devices(struct dm_table *t);
void dm_table_presuspend_targets(struct dm_table *t);
void dm_table_postsuspend_targets(struct dm_table *t);
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