Messages in this thread Patch in this message | | | From | Chanho Park <> | Subject | [PATCH] scsi: ufs: make sure scan sequence for multiple hosts | Date | Tue, 20 Oct 2020 17:44:22 +0900 |
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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@samsung.com> --- 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
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