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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Randy Dunlap <rdunlap@infradead.org>,
        Hussam Al-Tayeb <ht990332@gmx.com>,
        Bart Van Assche <bvanassche@acm.org>,
        "Martin K. Petersen" <martin.petersen@oracle.com>
Subject: [PATCH 4.9 29/56] scsi: sd: Quiesce warning if device does not report optimal I/O size
Date:   Mon,  1 Apr 2019 19:02:45 +0200
Message-Id: <20190401170105.533615559@linuxfoundation.org>
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4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Martin K. Petersen <martin.petersen@oracle.com>

commit 1d5de5bd311be7cd54f02f7cd164f0349a75c876 upstream.

Commit a83da8a4509d ("scsi: sd: Optimal I/O size should be a multiple
of physical block size") split one conditional into several separate
statements in an effort to provide more accurate warning messages when
a device reports a nonsensical value. However, this reorganization
accidentally dropped the precondition of the reported value being
larger than zero. This lead to a warning getting emitted on devices
that do not report an optimal I/O size at all.

Remain silent if a device does not report an optimal I/O size.

Fixes: a83da8a4509d ("scsi: sd: Optimal I/O size should be a multiple of physical block size")
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: <stable@vger.kernel.org>
Reported-by: Hussam Al-Tayeb <ht990332@gmx.com>
Tested-by: Hussam Al-Tayeb <ht990332@gmx.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/scsi/sd.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2841,6 +2841,9 @@ static bool sd_validate_opt_xfer_size(st
 	unsigned int opt_xfer_bytes =
 		logical_to_bytes(sdp, sdkp->opt_xfer_blocks);
 
+	if (sdkp->opt_xfer_blocks == 0)
+		return false;
+
 	if (sdkp->opt_xfer_blocks > dev_max) {
 		sd_first_printk(KERN_WARNING, sdkp,
 				"Optimal transfer size %u logical blocks " \