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From: Matthew Wilcox <matthew@wil.cx>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Alan Stern <stern@rowland.harvard.edu>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Hans de Goede <hdegoede@redhat.com>,
	Ben Hutchings <ben@decadent.org.uk>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"alan@lxorguk.ukuu.org.uk" <alan@lxorguk.ukuu.org.uk>,
	Matthew Dharm <mdharm-usb@one-eyed-alien.net>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-scsi <linux-scsi@vger.kernel.org>
Subject: Re: [ 38/48] SCSI & usb-storage: add try_rc_10_first flag
Date: Tue, 3 Jul 2012 14:35:12 -0600	[thread overview]
Message-ID: <20120703203512.GE28804@parisc-linux.org> (raw)
In-Reply-To: <1341346072.3076.6.camel@dabdike>

On Wed, Jul 04, 2012 at 12:07:52AM +0400, James Bottomley wrote:
> > The reason for the try_rc_10_first flag is that some devices return
> > bogus data in response to RC16.  Like, an 800 GB device claiming to
> > have 3 exabytes.
> 
> So we could easily send both and only believe RC10 if the device is
> under 2TB.  However, what about all the extra flags we read out of RC16,
> like trim, large sector size and DIF capability?  If the device lies
> about its capacity, won't we get bogus values for those as well, which
> is going to cause other screw ups?

I think the necessary algorithm is simpler than that:

Send RC10 (unless the device supports PI, in which case it's probably
	enterprisey and well-tested)
Send RC16
If RC10 capacity agrees with RC16 capacity, use extra RC16 data.
(for values of "agrees with" that include the "-1 to use RC16" indicator)

Sure, it's one extra command, but really, who cares?

-- 
Matthew Wilcox				Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."

  parent reply	other threads:[~2012-07-03 20:35 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20120701172006.535271340@decadent.org.uk>
2012-07-01 17:20 ` [ 01/48] staging:iio:ad7606: Re-add missing scale attribute Ben Hutchings
2012-07-01 17:20 ` [ 02/48] Tools: hv: verify origin of netlink connector message Ben Hutchings
2012-07-01 17:20 ` [ 03/48] edac: avoid mce decoding crash after edac driver unloaded Ben Hutchings
2012-07-01 17:20 ` [ 06/48] hwmon: (applesmc) Limit key length in warning messages Ben Hutchings
2012-07-01 17:20 ` [ 07/48] mm: fix slab->page _count corruption when using slub Ben Hutchings
2012-07-02 23:46   ` Herton Ronaldo Krzesinski
2012-07-02 23:56     ` Herton Ronaldo Krzesinski
2012-07-03  1:17       ` Herton Ronaldo Krzesinski
2012-07-03 20:19         ` Pravin Shelar
2012-07-04  4:36     ` Ben Hutchings
2012-07-01 17:20 ` [ 08/48] mm: pmd_read_atomic: fix 32bit PAE pmd walk vs pmd_populate SMP race condition Ben Hutchings
2012-07-01 17:20 ` [ 10/48] nilfs2: ensure proper cache clearing for gc-inodes Ben Hutchings
2012-07-01 17:20 ` [ 12/48] drm/i915: Finish any pending operations on the framebuffer before disabling Ben Hutchings
2012-07-01 17:20 ` [ 13/48] drm/i915: Remove use of the autoreported ringbuffer HEAD position Ben Hutchings
2012-07-01 17:20 ` [ 15/48] e1000e: Remove special case for 82573/82574 ASPM L1 disablement Ben Hutchings
2012-07-01 22:59   ` Jonathan Nieder
2012-07-01 17:20 ` [ 16/48] drm/i915: Do the fallback non-IRQ wait in ring throttle, too Ben Hutchings
2012-07-01 17:20 ` [ 17/48] staging:rts_pstor:Fix possible panic by NULL pointer dereference Ben Hutchings
2012-07-01 17:20 ` [ 21/48] drm/nouveau/fbcon: using nv_two_heads is not a good idea Ben Hutchings
2012-07-01 17:20 ` [ 29/48] ARM: SAMSUNG: Should check for IS_ERR(clk) instead of NULL Ben Hutchings
2012-07-01 17:20 ` [ 30/48] ath9k_hw: avoid possible infinite loop in ar9003_get_pll_sqsum_dvc Ben Hutchings
2012-07-01 17:20 ` [ 31/48] iwlwifi: remove log_event debugfs file debugging is disabled Ben Hutchings
2012-07-01 17:20 ` [ 32/48] ARM: SAMSUNG: Fix for S3C2412 EBI memory mapping Ben Hutchings
2012-07-01 17:20 ` [ 33/48] USB: option: add id for Cellient MEN-200 Ben Hutchings
2012-07-01 17:20 ` [ 34/48] oprofile: perf: use NR_CPUS instead or nr_cpumask_bits for static array Ben Hutchings
2012-07-01 17:20 ` [ 35/48] drm/i915: Refactor the deferred PM_IIR handling into a single function Ben Hutchings
2012-07-01 17:20 ` [ 36/48] drm/i915: rip out the PM_IIR WARN Ben Hutchings
2012-07-01 17:20 ` [ 37/48] drm/i915: Fix eDP blank screen after S3 resume on HP desktops Ben Hutchings
2012-07-01 17:20 ` [ 38/48] SCSI & usb-storage: add try_rc_10_first flag Ben Hutchings
2012-07-02  7:10   ` Hans de Goede
2012-07-02 18:52     ` Linus Torvalds
2012-07-02 20:39       ` James Bottomley
2012-07-02 22:23         ` Linus Torvalds
2012-07-03  0:41           ` Matthew Wilcox
2012-07-03  6:18             ` James Bottomley
2012-07-03 15:49               ` Alan Stern
2012-07-03 17:32                 ` Matthew Wilcox
2012-07-03 19:50                   ` Alan Stern
2012-07-03 20:07                     ` James Bottomley
2012-07-03 20:25                       ` Alan Stern
2012-07-03 20:35                       ` Matthew Wilcox [this message]
2012-07-05 21:40                         ` Alan Stern
2012-07-06  3:05                           ` Matthew Wilcox
2012-07-06 14:00                             ` Alan Stern
2012-07-04  4:39     ` Ben Hutchings
2012-07-01 17:20 ` [ 39/48] PM / Sleep: Prevent waiting forever on asynchronous suspend after abort Ben Hutchings
2012-07-01 17:20 ` [ 40/48] x86, cpufeature: Rename X86_FEATURE_DTS to X86_FEATURE_DTHERM Ben Hutchings
2012-07-01 17:20 ` [ 42/48] ALSA: hda - Add Realtek ALC280 codec support Ben Hutchings
2012-07-01 17:20 ` [ 43/48] USB: option: Add USB ID for Novatel Ovation MC551 Ben Hutchings
2012-07-01 17:20 ` [ 45/48] xen/netfront: teardown the device before unregistering it Ben Hutchings
2012-07-01 17:20 ` [ 46/48] can: flexcan: use be32_to_cpup to handle the value of dt entry Ben Hutchings
2012-07-01 17:20 ` [ 47/48] acpi_pad: fix power_saving thread deadlock Ben Hutchings
2012-07-01 17:20 ` [ 48/48] batman-adv: only drop packets of known wifi clients Ben Hutchings
2012-07-01 19:11 ` [ 00/48] 3.2.22-stable review Ben Hutchings

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