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Peter Anvin" , Ajay Kaher , Alexey Makhalov , Broadcom internal kernel review list , Paolo Bonzini , Vitaly Kuznetsov , Boris Ostrovsky , xen-devel@lists.xenproject.org, Jean Delvare , Guenter Roeck , Denis Efremov , Jens Axboe Subject: [PATCH 0/5] x86: Cleanups around slow_down_io() Date: Wed, 26 Nov 2025 17:20:13 +0100 Message-ID: <20251126162018.5676-1-jgross@suse.com> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: linux-hwmon@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[99.99%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_MISSING_CHARSET(0.50)[]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; RCVD_VIA_SMTP_AUTH(0.00)[]; MIME_TRACE(0.00)[0:+]; FUZZY_RATELIMITED(0.00)[rspamd.com]; RCPT_COUNT_TWELVE(0.00)[23]; ARC_NA(0.00)[]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; URIBL_BLOCKED(0.00)[suse.com:mid,imap1.dmz-prg2.suse.org:helo]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:mid,imap1.dmz-prg2.suse.org:helo]; RCVD_TLS_ALL(0.00)[] X-Spam-Level: X-Spam-Score: -2.80 X-Spam-Flag: NO 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