From: Hannes Reinecke <hare@suse.de>
To: Tejun Heo <tj@kernel.org>
Cc: Damien Le Moal <damien.lemoal@hgst.com>, linux-ide@vger.kernel.org
Subject: Re: [PATCH 4/6] ata: fixup ATA_PROT_NODATA
Date: Tue, 21 Jun 2016 07:52:30 +0200 [thread overview]
Message-ID: <5768D61E.1060203@suse.de> (raw)
In-Reply-To: <20160620154426.GL3262@mtj.duckdns.org>
On 06/20/2016 05:44 PM, Tejun Heo wrote:
> On Mon, Jun 20, 2016 at 01:39:14PM +0200, Hannes Reinecke wrote:
>> The taskfile protocol is a numeric value, and can not be ORed.
>>
>> Signed-off-by: Hannes Reinecke <hare@suse.de>
>> ---
>> drivers/ata/libata-core.c | 4 ++--
>> drivers/ata/libata-eh.c | 2 +-
>> 2 files changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
>> index e798915..d200102 100644
>> --- a/drivers/ata/libata-core.c
>> +++ b/drivers/ata/libata-core.c
>> @@ -1238,7 +1238,7 @@ static int ata_read_native_max_address(struct ata_device *dev, u64 *max_sectors)
>> } else
>> tf.command = ATA_CMD_READ_NATIVE_MAX;
>>
>> - tf.protocol |= ATA_PROT_NODATA;
>> + tf.protocol = ATA_PROT_NODATA;
>> tf.device |= ATA_LBA;
>
> Did the above lead to any actual brekage or was tf.protocol guaranteed
> to be zero always? I wish the patch description described what the
> stake of the patch is.
>
This is actually a cleanup; if tf.protocl is '0' we won't see any issues
here.
But if (for some obsure reason) tf.protocol is _not_ zero we'll run into
very obscure problems.
Plus the OR here might give others the wrong impression, and might lead
to a confusion between ATA_PROT_XXX (which is a scalar value and cannot
be ORed) and ATA_PROT_FLAG_XXX (which is a bit value and can be ORed).
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
next prev parent reply other threads:[~2016-06-21 5:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-20 11:39 [PATCH 0/6] libata: Fixup ATA NCQ NON-DATA commands Hannes Reinecke
2016-06-20 11:39 ` [PATCH 1/6] libata: use ata_is_ncq() accessors Hannes Reinecke
2016-06-20 11:39 ` [PATCH 2/6] libsas: use ata_is_ncq() and ata_has_dma() accessors Hannes Reinecke
2016-06-20 15:40 ` Tejun Heo
2016-06-21 5:44 ` Hannes Reinecke
2016-06-20 11:39 ` [PATCH 3/6] ata: add ata_is_fpdma() accessor Hannes Reinecke
2016-06-20 15:42 ` Tejun Heo
2016-06-21 5:49 ` Hannes Reinecke
2016-06-21 15:45 ` Tejun Heo
2016-06-20 11:39 ` [PATCH 4/6] ata: fixup ATA_PROT_NODATA Hannes Reinecke
2016-06-20 15:44 ` Tejun Heo
2016-06-21 5:52 ` Hannes Reinecke [this message]
2016-06-20 11:39 ` [PATCH 5/6] libata-eh: decode all taskfile protocols Hannes Reinecke
2016-06-20 11:39 ` [PATCH 6/6] ata: Handle ATA NCQ NO-DATA commands correctly Hannes Reinecke
2016-06-21 1:14 ` Damien Le Moal
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