By doing scan as asynchronous way, scsi device scannning can be out of
order execution. It is no problem if there is a ufs host but the scsi
device name of each host can be changed according to the scan sequences.
Ideal Case) host0 scan first
host0 will be started from /dev/sda
-> /dev/sdb (BootLUN0 of host0)
-> /dev/sdc (BootLUN1 of host1)
host1 will be started from /dev/sdd
This might be an ideal case and we can easily find the host device by
this mappinng.
However, Abnormal Case) host1 scan first,
host1 will be started from /dev/sda and host0 will be followed later.
To make sure the scan sequences according to the host, we can use a
bitmap which hosts are scanned and wait until previous hosts are
finished to scan.
Signed-off-by: Chanho Park <chanho61.park@xxxxxxxxxxx>
---
drivers/scsi/ufs/ufshcd.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index b8f573a02713..1ced5996e988 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -13,6 +13,7 @@
#include <linux/devfreq.h>
#include <linux/nls.h>
#include <linux/of.h>
+#include <linux/bitmap.h>
#include <linux/bitfield.h>
#include <linux/blk-pm.h>
#include <linux/blkdev.h>
@@ -214,6 +215,10 @@ static struct ufs_dev_fix ufs_fixups[] = {
END_FIX
};
+/* Ordered scan host */
+static unsigned long scanned_hosts = 0;
+static wait_queue_head_t scan_wq = __WAIT_QUEUE_HEAD_INITIALIZER(scan_wq);
+
static irqreturn_t ufshcd_tmc_handler(struct ufs_hba *hba);
static void ufshcd_async_scan(void *data, async_cookie_t cookie);
static int ufshcd_reset_and_restore(struct ufs_hba *hba);
@@ -7709,8 +7714,13 @@ static void ufshcd_async_scan(void *data, async_cookie_t cookie)
if (ret)
goto out;
- /* Probe and add UFS logical units */
+ /* Probe and add UFS logical units. Sequential scan by host_no */
+ wait_event(scan_wq,
+ find_first_zero_bit(&scanned_hosts, hba->host->max_id) ==
+ hba->host->host_no);
ret = ufshcd_add_lus(hba);
+ set_bit(hba->host->host_no, &scanned_hosts);
+ wake_up(&scan_wq);
out:
/*
* If we failed to initialize the device or the device is not
--
2.28.0
