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From: Willy Tarreau <w@1wt.eu>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Denis Efremov <efremov@linux.com>, Jens Axboe <axboe@kernel.dk>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-block <linux-block@vger.kernel.org>
Subject: Re: [PATCH 01/10] floppy: cleanup: expand macro FDCS
Date: Tue, 25 Feb 2020 19:15:41 +0100	[thread overview]
Message-ID: <20200225181541.GA1138@1wt.eu> (raw)
In-Reply-To: <CAHk-=wggnfCR2JcC-U9LxfeBo2UMagd-neEs8PwDHsGVfLfS=Q@mail.gmail.com>

On Tue, Feb 25, 2020 at 10:08:51AM -0800, Linus Torvalds wrote:
> On Tue, Feb 25, 2020 at 7:22 AM Denis Efremov <efremov@linux.com> wrote:
> >
> > I think that for the first attempt changing will be enough:
> > -static int fdc;                        /* current fdc */
> > +static int current_fdc;                        /* current fdc */
> > and
> > -#define FD_IOPORT fdc_state[fdc].address
> > +#define FD_IOPORT fdc_state[current_fdc].address
> 
> Please don't do this blindly - ie without verifying that there are no
> cases of that "local fdc variable shadowing" issue.

That's exactly what I'm doing. In fact I first renamed the variable
and am manually checking all places which do not compile anymore.
Hence the surprizes.

> Of course, such a verification might be as easy as "generates exact
> same code" rather than looking at every use.

That's exactly what I'm doing.

> And btw, don't worry too much about this being in an UAPI file. I'm
> pretty sure that's because of specialty programs that use the magical
> ioctls to do special formatting. They want the special commands
> (FD_FORMAT etc), but I don't think they really use the port addresses.
> 
> So I think it's in a UAPI file entirely by mistake.

OK this will help me, thanks for the hint :-)

> We should at least try moving those bits to the floppy.c file and
> remove it from the header file.

Makes sense.

> For example, doing a Debian code search on "FDPATCHES" doesn't find
> any user space hits. Searching for "FD_STATUS" gets a lot of hits, but
> thos all seem to be because it's a symbol used by user space programs,
> ("file descriptor status"), not because those hits actually used the
> fdreg.h header file.
> 
> So we can remove at least the FD_IOPORT mess from the header file, I bet.
> 
> Worst case - if somebody finds some case that uses them, we can put it back.

I like that. And at least we'll know how they use it (likely without the
dependency on fdc).

Thanks,
Willy

  reply	other threads:[~2020-02-25 18:15 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-24 21:23 [PATCH 00/10] floppy driver cleanups (deobfuscation) Willy Tarreau
2020-02-24 21:23 ` [PATCH 01/10] floppy: cleanup: expand macro FDCS Willy Tarreau
2020-02-24 21:53   ` Linus Torvalds
2020-02-24 23:13     ` Denis Efremov
2020-02-25  3:45       ` Willy Tarreau
2020-02-25  7:14         ` Denis Efremov
2020-02-25 14:02           ` Willy Tarreau
2020-02-25 15:22             ` Denis Efremov
2020-02-25 15:39               ` Denis Efremov
2020-02-25 16:12                 ` Willy Tarreau
2020-02-25 18:02               ` Willy Tarreau
2020-02-25 18:08                 ` Willy Tarreau
2020-02-25 18:08               ` Linus Torvalds
2020-02-25 18:15                 ` Willy Tarreau [this message]
2020-02-25 18:27                   ` Linus Torvalds
2020-02-26  8:18                 ` Willy Tarreau
2020-02-25 11:37   ` Denis Efremov
2020-02-24 21:23 ` [PATCH 02/10] floppy: cleanup: expand macro UFDCS Willy Tarreau
2020-02-24 21:23 ` [PATCH 03/10] floppy: cleanup: expand macro UDP Willy Tarreau
2020-02-24 21:23 ` [PATCH 04/10] floppy: cleanup: expand macro UDRS Willy Tarreau
2020-02-24 21:23 ` [PATCH 05/10] floppy: cleanup: expand macro UDRWE Willy Tarreau
2020-02-24 21:23 ` [PATCH 06/10] floppy: cleanup: expand macro DP Willy Tarreau
2020-02-24 21:23 ` [PATCH 07/10] floppy: cleanup: expand macro DRS Willy Tarreau
2020-02-24 21:23 ` [PATCH 08/10] floppy: cleanup: expand macro DRWE Willy Tarreau
2020-02-24 21:23 ` [PATCH 09/10] floppy: cleanup: expand the R/W / format command macros Willy Tarreau
2020-02-24 21:23 ` [PATCH 10/10] floppy: cleanup: expand the reply_buffer macros Willy Tarreau
2020-02-26  8:07 ` [PATCH 11/16] floppy: remove dead code for drives scanning on ARM Willy Tarreau
2020-02-26  8:07   ` [PATCH 12/16] floppy: remove incomplete support for second FDC from ARM code Willy Tarreau
2020-02-29 16:38     ` Denis Efremov
2020-02-26  8:07   ` [PATCH 13/16] floppy: prepare ARM code to simplify base address separation Willy Tarreau
2020-02-26  8:07   ` [PATCH 14/16] floppy: introduce new functions fdc_inb() and fdc_outb() Willy Tarreau
2020-02-26  8:07   ` [PATCH 15/16] floppy: separate the FDC's base address from its registers Willy Tarreau
2020-02-26 15:36     ` Denis Efremov
2020-02-26 15:46       ` Willy Tarreau
2020-02-26  8:07   ` [PATCH 16/16] floppy: rename the global "fdc" variable to "current_fdc" Willy Tarreau
2020-03-01  8:21   ` [PATCH 11/16] floppy: remove dead code for drives scanning on ARM Denis Efremov
2020-03-01  8:59     ` Willy Tarreau
2020-02-26 14:57 ` [PATCH 00/10] floppy driver cleanups (deobfuscation) Denis Efremov
2020-02-26 17:49   ` Linus Torvalds
2020-02-26 18:41     ` Willy Tarreau
2020-02-29 14:13     ` Willy Tarreau
2020-02-29 15:58       ` Linus Torvalds
2020-02-29 23:19         ` Ondrej Zary
2020-03-01  6:46           ` Willy Tarreau
2020-03-01 17:01             ` Ondrej Zary

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