From: Matthew Wilcox <willy@infradead.org>
To: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Vyacheslav Dubeyko <slava@dubeyko.com>,
Al Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 01/41] fs/adfs: inode: update timestamps to centisecond precision
Date: Mon, 9 Dec 2019 09:15:59 -0800 [thread overview]
Message-ID: <20191209171559.GF32169@bombadil.infradead.org> (raw)
In-Reply-To: <20191209143959.GL25745@shell.armlinux.org.uk>
On Mon, Dec 09, 2019 at 02:40:00PM +0000, Russell King - ARM Linux admin wrote:
> > Sounds good. :) But why namely 10000000?
>
> I don't know what you mean.
>
> If you're asking, why "10000000", isn't it obvious if you read the
> commit message? adfs has "centi-second" granularity. s_time_gran
> is in nanoseconds. There are 10000000 nanoseconds in a centisecond.
>
> What do you expect?
>
> #define ADFS_TIME_GRAN 10000000
>
> sb->s_time_gran = ADFS_TIME_GRAN;
>
> ?
>
> How does that help - it just stupidly and needlessly obfuscates the
> code.
>
> The whole "use definitions for constants" is idiotic when a constant
> is only used in one place - when it means you have to search through
> more source code to find it's single definition. Sorry, I'm not
> doing that and make readability *worse*.
I'd find it more readable if you wrote it as 10 * 1000 * 1000. Saves
trying to count zeroes. I know C added the ability to spell that as
10'000'000, but I don't think all compiler versions support that yet.
Maybe this would be cleanest:
sb->s_time_gran = NSEC_PER_SEC / 100;
This is definitely how not to do it:
include/acpi/actypes.h:#define ACPI_100NSEC_PER_SEC 10000000L
next prev parent reply other threads:[~2019-12-09 17:16 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-09 11:07 [PATCH 00/41] fs/adfs updates for 5.6 Russell King - ARM Linux admin
2019-12-09 11:08 ` [PATCH 01/41] fs/adfs: inode: update timestamps to centisecond precision Russell King
2019-12-09 13:54 ` Vyacheslav Dubeyko
2019-12-09 14:03 ` Russell King - ARM Linux admin
2019-12-09 14:34 ` Vyacheslav Dubeyko
2019-12-09 14:40 ` Russell King - ARM Linux admin
2019-12-09 17:15 ` Matthew Wilcox [this message]
2019-12-09 11:08 ` [PATCH 02/41] fs/adfs: inode: fix adfs_mode2atts() Russell King
2019-12-09 11:08 ` [PATCH 03/41] fs/adfs: map: move map reading and validation to map.c Russell King
2019-12-09 11:08 ` [PATCH 04/41] fs/adfs: map: rename adfs_map_free() to adfs_map_statfs() Russell King
2019-12-09 11:08 ` [PATCH 05/41] fs/adfs: map: break up adfs_read_map() Russell King
2019-12-09 11:08 ` [PATCH 06/41] fs/adfs: map: factor out map cleanup Russell King
2019-12-09 11:08 ` [PATCH 07/41] fs/adfs: map: incorporate map offsets into layout Russell King
2019-12-09 11:08 ` [PATCH 08/41] fs/adfs: map: use find_next_bit_le() rather than open coding it Russell King
2019-12-09 11:08 ` [PATCH 09/41] fs/adfs: map: move map-specific sb initialisation to map.c Russell King
2019-12-09 11:09 ` [PATCH 10/41] fs/adfs: map: fix map scanning Russell King
2019-12-09 11:09 ` [PATCH 11/41] fs/adfs: dir: rename bh_fplus to bhs Russell King
2019-12-09 11:09 ` [PATCH 12/41] fs/adfs: dir: add common dir object initialisation Russell King
2019-12-09 11:09 ` [PATCH 13/41] fs/adfs: dir: add common directory buffer release method Russell King
2019-12-09 11:09 ` [PATCH 14/41] fs/adfs: dir: add common directory sync method Russell King
2019-12-09 11:09 ` [PATCH 15/41] fs/adfs: dir: add generic copy functions Russell King
2019-12-09 11:09 ` [PATCH 16/41] fs/adfs: dir: add generic directory reading Russell King
2019-12-09 11:09 ` [PATCH 17/41] fs/adfs: dir: add helper to read directory using inode Russell King
2019-12-09 11:09 ` [PATCH 18/41] fs/adfs: dir: add helper to mark directory buffers dirty Russell King
2019-12-09 11:09 ` [PATCH 19/41] fs/adfs: dir: update directory locking Russell King
2019-12-09 11:09 ` [PATCH 20/41] fs/adfs: dir: modernise on-disk directory structures Russell King
2019-12-09 11:10 ` [PATCH 21/41] fs/adfs: dir: improve update failure handling Russell King
2019-12-09 11:10 ` [PATCH 22/41] fs/adfs: dir: improve compiler coverage in adfs_dir_update Russell King
2019-12-09 11:10 ` [PATCH 23/41] fs/adfs: dir: switch to iterate_shared method Russell King
2019-12-09 11:10 ` [PATCH 24/41] fs/adfs: dir: add more efficient iterate() per-format method Russell King
2019-12-09 11:10 ` [PATCH 25/41] fs/adfs: dir: use pointers to access directory head/tails Russell King
2019-12-09 11:10 ` [PATCH 26/41] fs/adfs: newdir: factor out directory format validation Russell King
2019-12-09 11:10 ` [PATCH 27/41] fs/adfs: newdir: improve directory validation Russell King
2019-12-09 11:10 ` [PATCH 28/41] fs/adfs: newdir: merge adfs_dir_read() into adfs_f_read() Russell King
2019-12-09 11:10 ` [PATCH 29/41] fs/adfs: newdir: clean up adfs_f_update() Russell King
2019-12-09 11:10 ` [PATCH 30/41] fs/adfs: newdir: split out directory commit from update Russell King
2019-12-09 11:10 ` [PATCH 31/41] fs/adfs: bigdir: factor out directory entry offset calculation Russell King
2019-12-09 11:10 ` [PATCH 32/41] fs/adfs: bigdir: extract directory validation Russell King
2019-12-09 11:11 ` [PATCH 33/41] fs/adfs: bigdir: directory validation strengthening Russell King
2019-12-09 11:11 ` [PATCH 34/41] fs/adfs: bigdir: calculate and validate directory checkbyte Russell King
2019-12-09 11:11 ` [PATCH 35/41] fs/adfs: bigdir: implement directory update support Russell King
2019-12-09 11:11 ` [PATCH 36/41] fs/adfs: super: fix inode dropping Russell King
2019-12-09 11:11 ` [PATCH 37/41] fs/adfs: dir: remove debug in adfs_dir_update() Russell King
2019-12-09 11:11 ` [PATCH 38/41] fs/adfs: super: extract filesystem block probe Russell King
2019-12-09 11:11 ` [PATCH 39/41] fs/adfs: super: add support for E and E+ floppy image formats Russell King
2019-12-09 11:11 ` [PATCH 40/41] fs/adfs: mostly divorse inode number from indirect disc address Russell King
2019-12-09 11:11 ` [PATCH 41/41] Documentation: update adfs filesystem documentation Russell King
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