From: Juergen Gross <jgross@suse.com>
To: David Vrabel <david.vrabel@citrix.com>,
Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org, xen-devel@lists.xenproject.org,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCHv3 2/2] xenfs: replace xenbus and privcmd with symlinks
Date: Wed, 29 Jun 2016 06:50:55 +0200 [thread overview]
Message-ID: <577353AF.8080506__37028.6530968317$1467175947$gmane$org@suse.com> (raw)
In-Reply-To: <1467137167-28546-3-git-send-email-david.vrabel@citrix.com>
On 28/06/16 20:06, David Vrabel wrote:
> /proc/xen/xenbus does not work correctly. A read blocked waiting for
> a xenstore message holds the mutex needed for atomic file position
> updates. This blocks any writes on the same file handle, which can
> deadlock if the write is needed to unblock the read.
>
> /proc/xen/xenbus is supposed to be identical to the character device
> /dev/xen/xenbus so replace the file with a symlink.
>
> Similarly, replace /proc/xen/privcmd with a symlink since it should be
> the same as /dev/xen/privcmd.
>
> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
> ---
> v2:
> - remove unneeded includes
> ---
I think you should make xen_xenbus_fops and xen_privcmd_fops static
now that they are no longer referenced by super.c
Juergen
> drivers/xen/xenfs/super.c | 10 ++++------
> 1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/xen/xenfs/super.c b/drivers/xen/xenfs/super.c
> index 8559a71..0f2e2cd 100644
> --- a/drivers/xen/xenfs/super.c
> +++ b/drivers/xen/xenfs/super.c
> @@ -18,8 +18,6 @@
> #include <xen/xen.h>
>
> #include "xenfs.h"
> -#include "../privcmd.h"
> -#include "../xenbus/xenbus_comms.h"
>
> #include <asm/xen/hypervisor.h>
>
> @@ -45,16 +43,16 @@ static const struct file_operations capabilities_file_ops = {
> static int xenfs_fill_super(struct super_block *sb, void *data, int silent)
> {
> static struct tree_descr xenfs_files[] = {
> - [2] = { "xenbus", &xen_xenbus_fops, S_IRUSR|S_IWUSR },
> + [2] = { "xenbus", NULL, S_IFLNK | S_IRWXUGO, "/dev/xen/xenbus" },
> { "capabilities", &capabilities_file_ops, S_IRUGO },
> - { "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR },
> + { "privcmd", NULL, S_IFLNK | S_IRWXUGO, "/dev/xen/privcmd" },
> {""},
> };
>
> static struct tree_descr xenfs_init_files[] = {
> - [2] = { "xenbus", &xen_xenbus_fops, S_IRUSR|S_IWUSR },
> + [2] = { "xenbus", NULL, S_IFLNK | S_IRWXUGO, "/dev/xen/xenbus" },
> { "capabilities", &capabilities_file_ops, S_IRUGO },
> - { "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR },
> + { "privcmd", NULL, S_IFLNK | S_IRWXUGO, "/dev/xen/privcmd" },
> { "xsd_kva", &xsd_kva_file_ops, S_IRUSR|S_IWUSR},
> { "xsd_port", &xsd_port_file_ops, S_IRUSR|S_IWUSR},
> #ifdef CONFIG_XEN_SYMS
>
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next prev parent reply other threads:[~2016-06-29 4:50 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-28 18:06 [PATCHv3 0/2] libfs, xenfs: replace /proc/xen/xenbus with a symlink David Vrabel
2016-06-28 18:06 ` [PATCHv3 1/2] libfs: allow simple_fill_super() to add symlinks David Vrabel
2016-07-11 9:38 ` David Vrabel
2016-06-28 18:06 ` [PATCHv3 2/2] xenfs: replace xenbus and privcmd with symlinks David Vrabel
2016-06-29 4:50 ` Juergen Gross [this message]
2016-08-23 0:47 ` [PATCHv3 0/2] libfs, xenfs: replace /proc/xen/xenbus with a symlink Doug Goldstein
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