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[SCSI] scsi_dh_alua: Store the PREF bit from RTPG 

PREF bit indicates preferred target port group for accessing a logical
unit. This bit is used to optimize the STPG command handling.

Signed-off-by: Babu Moger <babu.moger@netapp.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Moger, Babu 2012-03-27 20:56:08 +00:00 committed by James Bottomley
parent 4335d092a1
commit dcd3a754b8
1 changed files with 4 additions and 1 deletions
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5
drivers/scsi/device_handler/scsi_dh_alua.c
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@ -63,6 +63,7 @@ struct alua_dh_data {
int rel_port;
int tpgs;
int state;
int pref;
unsigned flags; /* used for optimizing STPG */
unsigned char inq[ALUA_INQUIRY_SIZE];
unsigned char *buff;
@ -558,14 +559,16 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
for (k = 4, ucp = h->buff + 4; k < len; k += off, ucp += off) {
if (h->group_id == (ucp[2] << 8) + ucp[3]) {
h->state = ucp[0] & 0x0f;
h->pref = ucp[0] >> 7;
valid_states = ucp[1];
}
off = 8 + (ucp[7] * 4);
}
sdev_printk(KERN_INFO, sdev,
"%s: port group %02x state %c supports %c%c%c%c%c%c%c\n",
"%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n",
ALUA_DH_NAME, h->group_id, print_alua_state(h->state),
h->pref ? "preferred" : "non-preferred",
valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',