From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Stefan Tauner <tauner@technikum-wien.at>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
linux-ide@vger.kernel.org
Subject: Re: Questions (and a possible bug) regarding the ata_device_blacklist and ATA_HORKAGE_ZERO_AFTER_TRIM
Date: Tue, 12 Oct 2021 23:19:18 -0400 [thread overview]
Message-ID: <yq15yu1pr9h.fsf@ca-mkp.ca.oracle.com> (raw)
In-Reply-To: <20210915183518.0947de73@legacy> (Stefan Tauner's message of "Wed, 15 Sep 2021 18:35:18 +0200")
Stefan,
> This is still the case (with Linux 5.10). I would have expected that
> to be non-zero for devices with ATA_HORKAGE_ZERO_AFTER_TRIM.
The short answer is that we have split things into two distinct
operations: Deallocating a block range and zeroing a block range. And as
a result, upper layers no longer have to know whether a discard is
deterministic or not. That is all handled at the bottom of the stack
where the requested operation is translated into something suitable for
the device in question.
Because of the semantic distinction between deallocating and zeroing a
block range, discard_zeroes_data always reports 0 on modern kernels.
This is done to make applications pick the zeroing operation over
discard when they want to clear a block range.
--
Martin K. Petersen Oracle Linux Engineering
prev parent reply other threads:[~2021-10-13 3:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-26 13:04 Questions (and a possible bug) regarding the ata_device_blacklist and ATA_HORKAGE_ZERO_AFTER_TRIM Stefan Tauner
2019-09-26 22:01 ` Martin K. Petersen
2021-09-15 16:35 ` Stefan Tauner
2021-10-13 3:19 ` Martin K. Petersen [this message]
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