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| author | Moger, Babu <Babu.Moger@netapp.com> | 2012-03-27 22:55:49 +0200 |
|---|---|---|
| committer | James Bottomley <JBottomley@Parallels.com> | 2012-04-23 20:28:07 +0200 |
| commit | 4335d092a1f28e17c5bafa6170bbf9599ca29c6a (patch) | |
| tree | b72bf29f5c241ef53a342dd9c926edd0b1b3074a /drivers | |
| parent | [SCSI] be2iscsi: Remove unused OFFSET_IN_PAGE() macro (diff) | |
| download | linux-4335d092a1f28e17c5bafa6170bbf9599ca29c6a.tar.xz linux-4335d092a1f28e17c5bafa6170bbf9599ca29c6a.zip | |
[SCSI] scsi_dh_alua: Inroduce the set_params interface scsi_dh_alua handler
Handler expects only one parameter to set the flag ALUA_OPTIMIZE_STPG.
This flag is used to optimize the STPG behaviour. There is no change in
behaviour by default.
For example, to set the flag pass the following parameters from multipath.conf
hardware_handler "2 alua 1"
Signed-off-by: Babu Moger <babu.moger@netapp.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/scsi/device_handler/scsi_dh_alua.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c index 04c5cea47a22..506206ae5755 100644 --- a/drivers/scsi/device_handler/scsi_dh_alua.c +++ b/drivers/scsi/device_handler/scsi_dh_alua.c @@ -55,11 +55,15 @@ #define ALUA_FAILOVER_TIMEOUT (60 * HZ) #define ALUA_FAILOVER_RETRIES 5 +/* flags passed from user level */ +#define ALUA_OPTIMIZE_STPG 1 + struct alua_dh_data { int group_id; int rel_port; int tpgs; int state; + unsigned flags; /* used for optimizing STPG */ unsigned char inq[ALUA_INQUIRY_SIZE]; unsigned char *buff; int bufflen; @@ -621,6 +625,37 @@ static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h) out: return err; } +/* + * alua_set_params - set/unset the optimize flag + * @sdev: device on the path to be activated + * params - parameters in the following format + * "no_of_params\0param1\0param2\0param3\0...\0" + * For example, to set the flag pass the following parameters + * from multipath.conf + * hardware_handler "2 alua 1" + */ +static int alua_set_params(struct scsi_device *sdev, const char *params) +{ + struct alua_dh_data *h = get_alua_data(sdev); + unsigned int optimize = 0, argc; + const char *p = params; + int result = SCSI_DH_OK; + + if ((sscanf(params, "%u", &argc) != 1) || (argc != 1)) + return -EINVAL; + + while (*p++) + ; + if ((sscanf(p, "%u", &optimize) != 1) || (optimize > 1)) + return -EINVAL; + + if (optimize) + h->flags |= ALUA_OPTIMIZE_STPG; + else + h->flags &= ~ALUA_OPTIMIZE_STPG; + + return result; +} /* * alua_activate - activate a path @@ -698,6 +733,7 @@ static struct scsi_device_handler alua_dh = { .prep_fn = alua_prep_fn, .check_sense = alua_check_sense, .activate = alua_activate, + .set_params = alua_set_params, .match = alua_match, }; |