From: Mike Christie <mchristi@redhat.com>
To: Bart Van Assche <bart.vanassche@sandisk.com>,
linux-scsi@vger.kernel.org, target-devel@vger.kernel.org,
socketpair@gmail.com
Cc: stable@vger.kernel.org
Subject: Re: [PATCH 1/2] scsi: fix max discard sectors calculation
Date: Mon, 16 May 2016 22:46:15 -0500 [thread overview]
Message-ID: <573A9407.1040402@redhat.com> (raw)
In-Reply-To: <573A4D60.7080902@sandisk.com>
On 05/16/2016 05:44 PM, Bart Van Assche wrote:
> On 05/16/2016 11:46 AM, mchristi@redhat.com wrote:
>> logical_block_size and max_blocks are 32 bits, so we can
>> overflow when trying to convert SCSI device blocks to linux
>> block layer sectors.
>>
>> Signed-off-by: Mike Christie <mchristi@redhat.com>
>> Cc: stable@vger.kernel.org
>>
>> ---
>> drivers/scsi/sd.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
>> index f52b74c..1668e1d 100644
>> --- a/drivers/scsi/sd.c
>> +++ b/drivers/scsi/sd.c
>> @@ -690,7 +690,8 @@ static void sd_config_discard(struct scsi_disk
>> *sdkp, unsigned int mode)
>> - blk_queue_max_discard_sectors(q, max_blocks * (logical_block_size
>> >> 9));
>> + blk_queue_max_discard_sectors(q, (u64)max_blocks *
>> + (logical_block_size >> 9));
>
> Hello Mike,
>
> As far as I can see max_blocks <= 0xffff (SD_MAX_WS10_BLOCKS) and 512 <=
> logical_block_size <= 4096. How can max_blocks * (logical_block_size >>
> 9) be too large for a 32 bit integer?
>
Oops yeah, you are right. I forgot I modified the code to test the
target patch. The patch is not needed. Thanks.
next prev parent reply other threads:[~2016-05-17 3:46 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-16 18:46 [PATCH 0/2] fix max discard sectors calculation mchristi
2016-05-16 18:46 ` [PATCH 1/2] scsi: " mchristi
2016-05-16 22:44 ` Bart Van Assche
2016-05-17 3:46 ` Mike Christie [this message]
2016-05-16 18:46 ` [PATCH 2/2] target: " mchristi
2016-05-16 18:57 ` Bart Van Assche
2016-05-16 19:00 ` Mike Christie
2016-05-16 19:02 ` Martin K. Petersen
2016-05-17 18:16 ` Bart Van Assche
2016-05-17 21:49 ` Mike Christie
2016-05-18 16:56 ` Bart Van Assche
2016-05-18 17:17 ` Mike Christie
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