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From: Juergen Gross <jgross@suse.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org,
	virtualization@lists.linux.dev, kvm@vger.kernel.org,
	linux-hwmon@vger.kernel.org, linux-block@vger.kernel.org
Cc: Juergen Gross <jgross@suse.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Ajay Kaher <ajay.kaher@broadcom.com>,
	Alexey Makhalov <alexey.makhalov@broadcom.com>,
	Broadcom internal kernel review list
	<bcm-kernel-feedback-list@broadcom.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	xen-devel@lists.xenproject.org, Jean Delvare <jdelvare@suse.com>,
	Guenter Roeck <linux@roeck-us.net>,
	Denis Efremov <efremov@linux.com>, Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 0/5] x86: Cleanups around slow_down_io()
Date: Wed, 26 Nov 2025 17:20:13 +0100	[thread overview]
Message-ID: <20251126162018.5676-1-jgross@suse.com> (raw)

While looking at paravirt cleanups I stumbled over slow_down_io() and
the related REALLY_SLOW_IO define.

Especially REALLY_SLOW_IO is a mess, which is proven by 2 completely
wrong use cases.

Do several cleanups, resulting in a deletion of REALLY_SLOW_IO and the
io_delay() paravirt function hook.

Patches 2 and 3 are not changing any functionality, but maybe they
should? As the potential bug has been present for more than a decade
now, I went with just deleting the useless "#define REALLY_SLOW_IO".
The alternative would be to do something similar as in patch 5.

Juergen Gross (5):
  x86/paravirt: Replace io_delay() hook with a bool
  hwmon/lm78: Drop REALLY_SLOW_IO setting
  hwmon/w83781d: Drop REALLY_SLOW_IO setting
  block/floppy: Don't use REALLY_SLOW_IO for delays
  x86/io: Remove REALLY_SLOW_IO handling

 arch/x86/include/asm/floppy.h         | 27 ++++++++++++++++++++++-----
 arch/x86/include/asm/io.h             | 12 +++++-------
 arch/x86/include/asm/paravirt.h       | 11 +----------
 arch/x86/include/asm/paravirt_types.h |  3 +--
 arch/x86/kernel/cpu/vmware.c          |  2 +-
 arch/x86/kernel/kvm.c                 |  8 +-------
 arch/x86/kernel/paravirt.c            |  3 +--
 arch/x86/xen/enlighten_pv.c           |  6 +-----
 drivers/block/floppy.c                |  2 --
 drivers/hwmon/lm78.c                  |  5 +++--
 drivers/hwmon/w83781d.c               |  5 +++--
 11 files changed, 39 insertions(+), 45 deletions(-)

-- 
2.51.0


             reply	other threads:[~2025-11-26 16:20 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-26 16:20 Juergen Gross [this message]
2025-11-26 16:20 ` [PATCH 1/5] x86/paravirt: Replace io_delay() hook with a bool Juergen Gross
2025-11-26 16:20 ` [PATCH 2/5] hwmon/lm78: Drop REALLY_SLOW_IO setting Juergen Gross
2025-11-26 17:04   ` Guenter Roeck
2025-11-26 16:20 ` [PATCH 3/5] hwmon/w83781d: " Juergen Gross
2025-11-26 17:05   ` Guenter Roeck
2025-11-26 16:20 ` [PATCH 4/5] block/floppy: Don't use REALLY_SLOW_IO for delays Juergen Gross
2025-11-26 16:20 ` [PATCH 5/5] x86/io: Remove REALLY_SLOW_IO handling Juergen Gross
2025-11-26 17:08 ` [PATCH 0/5] x86: Cleanups around slow_down_io() Guenter Roeck
2025-12-14  8:05 ` Ingo Molnar
2025-12-15  6:36   ` Jürgen Groß
2025-12-16 13:48     ` Ingo Molnar
2025-12-16 13:55       ` Jürgen Groß
2025-12-16 15:32         ` H. Peter Anvin
2025-12-16 19:59           ` David Laight
2025-12-16 21:50             ` H. Peter Anvin

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