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From: Al Viro <viro@zeniv.linux.org.uk>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-fsdevel@vger.kernel.org, brauner@kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] timerfd: convert to ->read_iter()
Date: Wed, 3 Apr 2024 23:40:37 +0100	[thread overview]
Message-ID: <20240403224037.GM538574@ZenIV> (raw)
In-Reply-To: <20240403140446.1623931-2-axboe@kernel.dk>

On Wed, Apr 03, 2024 at 08:02:52AM -0600, Jens Axboe wrote:

> -		res = put_user(ticks, (u64 __user *) buf) ? -EFAULT: sizeof(ticks);
> +		res = copy_to_iter(&ticks, sizeof(ticks), to);

Umm...  That's not an equivalent transformation - different behaviour on
short copy; try to call it via read(fd, unmapped_buffer, 8) and see what
happens.

copy_to_iter() returns the amount copied; no data copied => return 0, not -EFAULT.

> +	ufd = get_unused_fd_flags(O_RDWR | (flags & TFD_SHARED_FCNTL_FLAGS));

You do realize that get_unused_fd_flags() ignores O_RDWR (or O_NDELAY), right?
Mixing those with O_CLOEXEC makes sense for anon_inode_getfd(), but here you
have separate calls of get_unused_fd_flags() and anon_inode_getfile(), so...

  reply	other threads:[~2024-04-03 22:40 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-03 14:02 [PATCHSET v2 0/3] Convert fs drivers to ->read_iter() Jens Axboe
2024-04-03 14:02 ` [PATCH 1/3] timerfd: convert " Jens Axboe
2024-04-03 22:40   ` Al Viro [this message]
2024-04-04 12:51     ` Jens Axboe
2024-04-03 14:02 ` [PATCH 2/3] userfaultfd: " Jens Axboe
2024-04-03 22:45   ` Al Viro
2024-04-03 14:02 ` [PATCH 3/3] signalfd: " Jens Axboe
2024-04-03 22:57   ` Al Viro
2024-04-04 12:52     ` Jens Axboe
  -- strict thread matches above, loose matches on Subject: below --
2024-04-02 20:18 [PATCHSET 0/3] Convert fs drivers " Jens Axboe
2024-04-02 20:18 ` [PATCH 1/3] timerfd: convert " Jens Axboe

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