From: Oleg Nesterov <oleg@redhat.com>
To: Christian Brauner <christian@brauner.io>
Cc: viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org,
torvalds@linux-foundation.org, fweimer@redhat.com,
jannh@google.com, tglx@linutronix.de, arnd@arndb.de,
shuah@kernel.org, dhowells@redhat.com, tkjos@android.com,
ldv@altlinux.org, miklos@szeredi.hu, linux-alpha@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org,
linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org,
linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-s390@vger.kernel.org, linux-sh@vger.kernel.org,
sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org,
linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org,
x86@kernel.org
Subject: Re: [PATCH v1 1/2] open: add close_range()
Date: Wed, 22 May 2019 18:57:37 +0200 [thread overview]
Message-ID: <20190522165737.GC4915@redhat.com> (raw)
In-Reply-To: <20190522155259.11174-1-christian@brauner.io>
On 05/22, Christian Brauner wrote:
>
> +static struct file *pick_file(struct files_struct *files, unsigned fd)
> {
> - struct file *file;
> + struct file *file = NULL;
> struct fdtable *fdt;
>
> spin_lock(&files->file_lock);
> @@ -632,15 +629,65 @@ int __close_fd(struct files_struct *files, unsigned fd)
> goto out_unlock;
> rcu_assign_pointer(fdt->fd[fd], NULL);
> __put_unused_fd(files, fd);
> - spin_unlock(&files->file_lock);
> - return filp_close(file, files);
>
> out_unlock:
> spin_unlock(&files->file_lock);
> - return -EBADF;
> + return file;
...
> +int __close_range(struct files_struct *files, unsigned fd, unsigned max_fd)
> +{
> + unsigned int cur_max;
> +
> + if (fd > max_fd)
> + return -EINVAL;
> +
> + rcu_read_lock();
> + cur_max = files_fdtable(files)->max_fds;
> + rcu_read_unlock();
> +
> + /* cap to last valid index into fdtable */
> + if (max_fd >= cur_max)
> + max_fd = cur_max - 1;
> +
> + while (fd <= max_fd) {
> + struct file *file;
> +
> + file = pick_file(files, fd++);
Well, how about something like
static unsigned int find_next_opened_fd(struct fdtable *fdt, unsigned start)
{
unsigned int maxfd = fdt->max_fds;
unsigned int maxbit = maxfd / BITS_PER_LONG;
unsigned int bitbit = start / BITS_PER_LONG;
bitbit = find_next_bit(fdt->full_fds_bits, maxbit, bitbit) * BITS_PER_LONG;
if (bitbit > maxfd)
return maxfd;
if (bitbit > start)
start = bitbit;
return find_next_bit(fdt->open_fds, maxfd, start);
}
unsigned close_next_fd(struct files_struct *files, unsigned start, unsigned maxfd)
{
unsigned fd;
struct file *file;
struct fdtable *fdt;
spin_lock(&files->file_lock);
fdt = files_fdtable(files);
fd = find_next_opened_fd(fdt, start);
if (fd >= fdt->max_fds || fd > maxfd) {
fd = -1;
goto out;
}
file = fdt->fd[fd];
rcu_assign_pointer(fdt->fd[fd], NULL);
__put_unused_fd(files, fd);
out:
spin_unlock(&files->file_lock);
if (fd == -1u)
return fd;
filp_close(file, files);
return fd + 1;
}
?
Then close_range() can do
while (fd < max_fd)
fd = close_next_fd(fd, maxfd);
Oleg.
next prev parent reply other threads:[~2019-05-22 16:58 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-22 15:52 [PATCH v1 1/2] open: add close_range() Christian Brauner
2019-05-22 15:52 ` [PATCH v1 2/2] tests: add close_range() tests Christian Brauner
2019-05-22 16:57 ` Oleg Nesterov [this message]
2019-05-23 11:51 ` [PATCH v1 1/2] open: add close_range() Christian Brauner
2019-05-23 14:14 ` Christian Brauner
2019-05-23 14:28 ` Christian Brauner
2019-05-23 16:21 ` Oleg Nesterov
2019-05-23 14:32 ` Jann Horn
2019-05-23 14:37 ` Christian Brauner
2019-05-23 16:22 ` Konstantin Khlebnikov
2019-05-23 16:29 ` David Laight
2019-05-23 16:33 ` Christian Brauner
2019-05-24 7:43 ` Arnd Bergmann
2019-05-24 9:57 ` Christian Brauner
2019-05-24 10:31 ` Christian Brauner
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