[PATCH 03/13] scsi: hisi_sas: Change common allocation mode of device id

From: John Garry
Date: Mon May 21 2018 - 05:19:57 EST


From: Xiang Chen <chenxiang66@xxxxxxxxxxxxx>

To reduce possibility of hitting unknown SoC bugs and aid
debugging and test, change allocation mode of device id from
last used device id instead of lowest available index.

Signed-off-by: Xiang Chen <chenxiang66@xxxxxxxxxxxxx>
Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
---
drivers/scsi/hisi_sas/hisi_sas.h | 1 +
drivers/scsi/hisi_sas/hisi_sas_main.c | 6 +++++-
2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/hisi_sas/hisi_sas.h b/drivers/scsi/hisi_sas/hisi_sas.h
index 3c88400..b4717bd 100644
--- a/drivers/scsi/hisi_sas/hisi_sas.h
+++ b/drivers/scsi/hisi_sas/hisi_sas.h
@@ -275,6 +275,7 @@ struct hisi_hba {

int slot_index_count;
int last_slot_index;
+ int last_dev_id;
unsigned long *slot_index_tags;
unsigned long reject_stp_links_msk;

diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c
index 1d300a2..04a3eb4 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_main.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
@@ -596,10 +596,12 @@ static struct hisi_sas_device *hisi_sas_alloc_dev(struct domain_device *device)
struct hisi_hba *hisi_hba = dev_to_hisi_hba(device);
struct hisi_sas_device *sas_dev = NULL;
unsigned long flags;
+ int last = hisi_hba->last_dev_id;
+ int first = (hisi_hba->last_dev_id + 1) % HISI_SAS_MAX_DEVICES;
int i;

spin_lock_irqsave(&hisi_hba->lock, flags);
- for (i = 0; i < HISI_SAS_MAX_DEVICES; i++) {
+ for (i = first; i != last; i %= HISI_SAS_MAX_DEVICES) {
if (hisi_hba->devices[i].dev_type == SAS_PHY_UNUSED) {
int queue = i % hisi_hba->queue_count;
struct hisi_sas_dq *dq = &hisi_hba->dq[queue];
@@ -614,7 +616,9 @@ static struct hisi_sas_device *hisi_sas_alloc_dev(struct domain_device *device)
INIT_LIST_HEAD(&hisi_hba->devices[i].list);
break;
}
+ i++;
}
+ hisi_hba->last_dev_id = i;
spin_unlock_irqrestore(&hisi_hba->lock, flags);

return sas_dev;
--
1.9.1