All of lore.kernel.org
 help / color / mirror / Atom feed
From: Andy Lutomirski <luto@amacapital.net>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Luck, Tony" <tony.luck@intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Borislav Petkov <bp@alien8.de>, stable <stable@vger.kernel.org>,
	the arch/x86 maintainers <x86@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Paul Mackerras <paulus@samba.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Erwin Tsaur <erwin.tsaur@intel.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	linux-nvdimm <linux-nvdimm@lists.01.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 0/2] Replace and improve "mcsafe" with copy_safe()
Date: Thu, 30 Apr 2020 18:10:08 -0700	[thread overview]
Message-ID: <1AA57F55-0361-4230-82B3-B432C40C0DBC@amacapital.net> (raw)
In-Reply-To: <CAHk-=wgeMRm_yhb_fwvmgdaPMYzgXY01cYvw5htHUCTwSzswqg@mail.gmail.com>



> On Apr 30, 2020, at 5:40 PM, Linus Torvalds <torvalds@linux-foundation.org> wrote:
> 
> On Thu, Apr 30, 2020 at 5:23 PM Andy Lutomirski <luto@amacapital.net> wrote:
>> 
>>> But anyway, I don't hate something like "copy_to_user_fallible()"
>>> conceptually. The naming needs to be fixed, in that "user" can always
>>> take a fault, so it's the _source_ that can fault, not the "user"
>>> part.
>> 
>> I don’t like this.  “user” already implied that basically anything can be wrong with the memory
> 
> Maybe I didn't explain.
> 
> "user" already implies faulting. We agree.
> 
> And since we by definition cannot know what the user has mapped into
> user space, *every* normal copy_to_user() has to be able to handle
> whatever faults that throws at us.
> 
> The reason I dislike "copy_to_user_fallible()" is that the user side
> already has that 'fallible".
> 
> If it's the _source_ being "fallible" (it really needs a better name -
> I will not call it just "f") then it should be "copy_f_to_user()".
> 
> That would be ok.
> 
> So "copy_f_to_user()" makes sense. But "copy_to_user_f()" does not.
> That puts the "f" on the "user", which we already know can fault.
> 
> See what I want in the name? I want the name to say which side can
> cause problems!

We are in violent agreement. I’m moderately confident that I never suggested copy_from_user_f(). We appear to agree completely.
_______________________________________________
Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
To unsubscribe send an email to linux-nvdimm-leave@lists.01.org

WARNING: multiple messages have this Message-ID (diff)
From: Andy Lutomirski <luto@amacapital.net>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>,
	"Luck, Tony" <tony.luck@intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Borislav Petkov <bp@alien8.de>, stable <stable@vger.kernel.org>,
	the arch/x86 maintainers <x86@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Paul Mackerras <paulus@samba.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Erwin Tsaur <erwin.tsaur@intel.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	linux-nvdimm <linux-nvdimm@lists.01.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 0/2] Replace and improve "mcsafe" with copy_safe()
Date: Thu, 30 Apr 2020 18:10:08 -0700	[thread overview]
Message-ID: <1AA57F55-0361-4230-82B3-B432C40C0DBC@amacapital.net> (raw)
In-Reply-To: <CAHk-=wgeMRm_yhb_fwvmgdaPMYzgXY01cYvw5htHUCTwSzswqg@mail.gmail.com>



> On Apr 30, 2020, at 5:40 PM, Linus Torvalds <torvalds@linux-foundation.org> wrote:
> 
> On Thu, Apr 30, 2020 at 5:23 PM Andy Lutomirski <luto@amacapital.net> wrote:
>> 
>>> But anyway, I don't hate something like "copy_to_user_fallible()"
>>> conceptually. The naming needs to be fixed, in that "user" can always
>>> take a fault, so it's the _source_ that can fault, not the "user"
>>> part.
>> 
>> I don’t like this.  “user” already implied that basically anything can be wrong with the memory
> 
> Maybe I didn't explain.
> 
> "user" already implies faulting. We agree.
> 
> And since we by definition cannot know what the user has mapped into
> user space, *every* normal copy_to_user() has to be able to handle
> whatever faults that throws at us.
> 
> The reason I dislike "copy_to_user_fallible()" is that the user side
> already has that 'fallible".
> 
> If it's the _source_ being "fallible" (it really needs a better name -
> I will not call it just "f") then it should be "copy_f_to_user()".
> 
> That would be ok.
> 
> So "copy_f_to_user()" makes sense. But "copy_to_user_f()" does not.
> That puts the "f" on the "user", which we already know can fault.
> 
> See what I want in the name? I want the name to say which side can
> cause problems!

We are in violent agreement. I’m moderately confident that I never suggested copy_from_user_f(). We appear to agree completely.


  reply	other threads:[~2020-05-01  1:10 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-30  8:24 [PATCH v2 0/2] Replace and improve "mcsafe" with copy_safe() Dan Williams
2020-04-30  8:24 ` Dan Williams
2020-04-30  8:25 ` [PATCH v2 1/2] copy_safe: Rename memcpy_mcsafe() to copy_safe() Dan Williams
2020-04-30  8:25   ` Dan Williams
2020-05-01  2:55   ` Sasha Levin
2020-04-30  8:25 ` [PATCH v2 2/2] x86/copy_safe: Introduce copy_safe_fast() Dan Williams
2020-04-30  8:25   ` Dan Williams
2020-05-01  2:55   ` Sasha Levin
2020-04-30 14:02 ` [PATCH v2 0/2] Replace and improve "mcsafe" with copy_safe() Linus Torvalds
2020-04-30 14:02   ` Linus Torvalds
2020-04-30 16:51   ` Andy Lutomirski
2020-04-30 16:51     ` Andy Lutomirski
2020-04-30 17:17     ` Linus Torvalds
2020-04-30 17:17       ` Linus Torvalds
2020-04-30 18:42       ` Andy Lutomirski
2020-04-30 18:42         ` Andy Lutomirski
2020-04-30 19:22         ` Luck, Tony
2020-04-30 19:22           ` Luck, Tony
2020-04-30 19:50           ` Linus Torvalds
2020-04-30 19:50             ` Linus Torvalds
2020-04-30 20:25             ` Luck, Tony
2020-04-30 20:25               ` Luck, Tony
2020-04-30 23:52             ` Dan Williams
2020-04-30 23:52               ` Dan Williams
2020-05-01  0:10               ` Linus Torvalds
2020-05-01  0:10                 ` Linus Torvalds
2020-05-01  0:23                 ` Andy Lutomirski
2020-05-01  0:23                   ` Andy Lutomirski
2020-05-01  0:39                   ` Linus Torvalds
2020-05-01  0:39                     ` Linus Torvalds
2020-05-01  1:10                     ` Andy Lutomirski [this message]
2020-05-01  1:10                       ` Andy Lutomirski
2020-05-01 14:09                   ` Luck, Tony
2020-05-01 14:09                     ` Luck, Tony
2020-05-03  0:29                     ` Andy Lutomirski
2020-05-03  0:29                       ` Andy Lutomirski
2020-05-04 20:05                       ` Luck, Tony
2020-05-04 20:05                         ` Luck, Tony
2020-05-04 20:26                         ` Andy Lutomirski
2020-05-04 20:26                           ` Andy Lutomirski
2020-05-04 21:30                           ` Dan Williams
2020-05-04 21:30                             ` Dan Williams
2020-05-01  0:24                 ` Linus Torvalds
2020-05-01  0:24                   ` Linus Torvalds
2020-05-01  1:20                   ` Andy Lutomirski
2020-05-01  1:20                     ` Andy Lutomirski
2020-05-01  1:21                 ` Dan Williams
2020-05-01  1:21                   ` Dan Williams
2020-05-01 18:28                   ` Linus Torvalds
2020-05-01 18:28                     ` Linus Torvalds
2020-05-01 20:17                     ` Dave Hansen
2020-05-01 20:17                       ` Dave Hansen
2020-05-03 12:57                     ` David Laight
2020-05-03 12:57                       ` David Laight
2020-05-04 18:33                       ` Dan Williams
2020-05-04 18:33                         ` Dan Williams
2020-05-11 15:24                   ` Vivek Goyal
2020-05-11 15:24                     ` Vivek Goyal
2020-04-30 19:51           ` Dan Williams
2020-04-30 19:51             ` Dan Williams
2020-04-30 20:07             ` Andy Lutomirski
2020-04-30 20:07               ` Andy Lutomirski
2020-05-01  7:46         ` David Laight
2020-05-01  7:46           ` David Laight

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1AA57F55-0361-4230-82B3-B432C40C0DBC@amacapital.net \
    --to=luto@amacapital.net \
    --cc=acme@kernel.org \
    --cc=benh@kernel.crashing.org \
    --cc=bp@alien8.de \
    --cc=erwin.tsaur@intel.com \
    --cc=hpa@zytor.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-nvdimm@lists.01.org \
    --cc=luto@kernel.org \
    --cc=mingo@redhat.com \
    --cc=mpe@ellerman.id.au \
    --cc=paulus@samba.org \
    --cc=peterz@infradead.org \
    --cc=stable@vger.kernel.org \
    --cc=tglx@linutronix.de \
    --cc=tony.luck@intel.com \
    --cc=torvalds@linux-foundation.org \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.