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authorTejun Heo <tj@kernel.org>2010-07-02 10:03:52 +0200
committerTejun Heo <tj@kernel.org>2010-07-02 10:59:24 +0200
commitad72cf9885c536e3adae03f8337557ac9dd1e4bb (patch)
treee93af7f241987ffe365792c0130d182b0ac890d1 /include/linux
parentd313dd85ad846bc768d58e9ceb28588f917f4c9a (diff)
libata: take advantage of cmwq and remove concurrency limitations
libata has two concurrency related limitations. a. ata_wq which is used for polling PIO has single thread per CPU. If there are multiple devices doing polling PIO on the same CPU, they can't be executed simultaneously. b. ata_aux_wq which is used for SCSI probing has single thread. In cases where SCSI probing is stalled for extended period of time which is possible for ATAPI devices, this will stall all probing. #a is solved by increasing maximum concurrency of ata_wq. Please note that polling PIO might be used under allocation path and thus needs to be served by a separate wq with a rescuer. #b is solved by using the default wq instead and achieving exclusion via per-port mutex. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Jeff Garzik <jgarzik@pobox.com>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/libata.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/libata.h b/include/linux/libata.h
index b85f3ff34d7d..f010f18a0f86 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -751,6 +751,7 @@ struct ata_port {
struct ata_host *host;
struct device *dev;
+ struct mutex scsi_scan_mutex;
struct delayed_work hotplug_task;
struct work_struct scsi_rescan_task;