Hi, This is a patch to fix SCSI timeout error recovery issue which I posted about one week ago. [RFC] SCSI timeout error recovery issue http://marc.info/?l=linux-scsi&m=124042136915970&w=2 scsi timeout on two or more devices may cause extremely long execution time for user applications because SDEV_OFFLINE state is changed to SDEV_RUNNING state during scsi error recovery procedures triggered by a bus reset or a host reset of LLD, and scsi timeout can happens on the same devices many times. This happens because scsi_internal_device_unblock() changes device's state to SDEV_RUNNING even if a device in other states than SDEV_BLOCK, but scsi_internal_device_block() is a pair with scsi_internal_device_unblock() and only devices in SDEV_BLOCK state are needed to be changed. This patch adds a check of the current device state so that state change and queue activation is not executed for devices in SDEV_BLOCK state. This patch is based on the idea that devices in SDEV_OFFLINE state need to stay in SDEV_OFFLINE because SDEV_OFFLINE state is done by: - All recovery procedures, bus reset and host reset, has already failed for devices in SDEV_OFFLINE state. (There is no (or rare?) chance to be recovered.) - A user has changed the device's state to SDEV_OFFLINE intentionally by an interface such as sysfs. (A user needs to enable devices in SDEV_OFFLINE state before using them again.) I appreciate any comments and suggestions on this patch. Regards, --- Takahiro Yasui Hitachi Computer Products (America), Inc. Signed-off-by: Takahiro Yasui <tyasui@xxxxxxxxxx> --- drivers/scsi/scsi_lib.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) Index: linux-2.6.29/drivers/scsi/scsi_lib.c =================================================================== --- linux-2.6.29.orig/drivers/scsi/scsi_lib.c +++ linux-2.6.29/drivers/scsi/scsi_lib.c @@ -2633,9 +2633,12 @@ scsi_internal_device_unblock(struct scsi unsigned long flags; /* - * Try to transition the scsi device to SDEV_RUNNING - * and goose the device queue if successful. + * Try to transition the scsi device to SDEV_RUNNING if it is + * SDEV_BLOCK and goose the device queue if successful. */ + if (sdev->sdev_state != SDEV_BLOCK) + return 0; + err = scsi_device_set_state(sdev, SDEV_RUNNING); if (err) { err = scsi_device_set_state(sdev, SDEV_CREATED); -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
