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authorNeilBrown <neilb@suse.de>2011-01-13 20:00:01 +0000
committerAlasdair G Kergon <agk@redhat.com>2011-01-13 20:00:01 +0000
commit9d357b0787bb3c91835d5e658c3bda178f9ca419 (patch)
tree48f2c3adc8ae06918ef0523f073291990407fa28 /include/linux/device-mapper.h
parent4e2d19e46b507018c6ed15f6c081d8f887ae229c (diff)
downloadop-kernel-dev-9d357b0787bb3c91835d5e658c3bda178f9ca419.zip
op-kernel-dev-9d357b0787bb3c91835d5e658c3bda178f9ca419.tar.gz
dm: introduce target callbacks and congestion callback
DM currently implements congestion checking by checking on congestion in each component device. For raid456 we need to also check if the stripe cache is congested. Add per-target congestion checker callback support. Extending the target_callbacks structure with additional callback functions allows for establishing multiple callbacks per-target (a callback is also needed for unplug). Cc: linux-raid@vger.kernel.org Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'include/linux/device-mapper.h')
-rw-r--r--include/linux/device-mapper.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 2970022..4b1c63d 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -193,6 +193,12 @@ struct dm_target {
char *error;
};
+/* Each target can link one of these into the table */
+struct dm_target_callbacks {
+ struct list_head list;
+ int (*congested_fn) (struct dm_target_callbacks *, int);
+};
+
int dm_register_target(struct target_type *t);
void dm_unregister_target(struct target_type *t);
@@ -269,6 +275,11 @@ int dm_table_add_target(struct dm_table *t, const char *type,
sector_t start, sector_t len, char *params);
/*
+ * Target_ctr should call this if it needs to add any callbacks.
+ */
+void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
+
+/*
* Finally call this to make the table ready for use.
*/
int dm_table_complete(struct dm_table *t);
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