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Date:   Tue, 23 Feb 2021 12:54:22 -0300
From:   Enzo Matsumiya <ematsumiya@suse.de>
To:     linux-scsi@vger.kernel.org
Cc:     Don Brace <don.brace@microchip.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        storagedev@microchip.com, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] scsi: smartpqi: create module parameters for LUN
 reset
Message-ID: <20210223155422.d7x5zm5ozot6dmaq@hyori>
References: <20210121170339.11891-1-ematsumiya@suse.de>
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In-Reply-To: <20210121170339.11891-1-ematsumiya@suse.de>
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Hi,

On 01/21, Enzo Matsumiya wrote:
>Commit c2922f174fa0 ("scsi: smartpqi: fix LUN reset when fw bkgnd thread is hung")
>added support for a timeout on LUN resets.
>
>However, when there are 2 or more devices connected to the same
>controller and you hot-remove one of them, I/O will stall on the
>devices still online for PQI_LUN_RESET_RETRIES * PQI_LUN_RESET_RETRY_INTERVAL_MSECS
>miliseconds.
>
>This commit makes those values configurable via module parameters.
>
>Changing the bail out condition on rc in _pqi_device_reset() might be possible,
>but could also break the original purpose of commit c2922f174fa0.
>
>Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>
>---
> drivers/scsi/smartpqi/smartpqi_init.c | 18 ++++++++++++++----
> 1 file changed, 14 insertions(+), 4 deletions(-)
>
>diff --git a/drivers/scsi/smartpqi/smartpqi_init.c b/drivers/scsi/smartpqi/smartpqi_init.c
>index c53f456fbd09..9835b2e5b91a 100644
>--- a/drivers/scsi/smartpqi/smartpqi_init.c
>+++ b/drivers/scsi/smartpqi/smartpqi_init.c
>@@ -157,6 +157,18 @@ module_param_named(hide_vsep,
> MODULE_PARM_DESC(hide_vsep,
> 	"Hide the virtual SEP for direct attached drives.");
>
>+static int pqi_lun_reset_retries = 3;
>+module_param_named(lun_reset_retries,
>+	pqi_lun_reset_retries, int, 0644);
>+MODULE_PARM_DESC(lun_reset_retries,
>+	"Number of retries when resetting a LUN");
>+
>+static int pqi_lun_reset_tmo_interval = 10000;
>+module_param_named(lun_reset_tmo_interval,
>+	pqi_lun_reset_tmo_interval, int, 0644);
>+MODULE_PARM_DESC(lun_reset_tmo_interval,
>+	"LUN reset timeout interval (in miliseconds)");
>+
> static char *raid_levels[] = {
> 	"RAID-0",
> 	"RAID-4",
>@@ -5687,8 +5699,6 @@ static int pqi_lun_reset(struct pqi_ctrl_info *ctrl_info,
>
> /* Performs a reset at the LUN level. */
>
>-#define PQI_LUN_RESET_RETRIES			3
>-#define PQI_LUN_RESET_RETRY_INTERVAL_MSECS	10000
> #define PQI_LUN_RESET_PENDING_IO_TIMEOUT_SECS	120
>
> static int _pqi_device_reset(struct pqi_ctrl_info *ctrl_info,
>@@ -5700,9 +5710,9 @@ static int _pqi_device_reset(struct pqi_ctrl_info *ctrl_info,
>
> 	for (retries = 0;;) {
> 		rc = pqi_lun_reset(ctrl_info, device);
>-		if (rc == 0 || ++retries > PQI_LUN_RESET_RETRIES)
>+		if (rc == 0 || ++retries > pqi_lun_reset_retries)
> 			break;
>-		msleep(PQI_LUN_RESET_RETRY_INTERVAL_MSECS);
>+		msleep(pqi_lun_reset_tmo_interval);
> 	}
>
> 	timeout_secs = rc ? PQI_LUN_RESET_PENDING_IO_TIMEOUT_SECS : NO_TIMEOUT;
>-- 
>2.30.0
>

Can anyone give me some feedback on this please?


Cheers,

Enzo