Re: [PATCH 2/4] cifs, freezer: add wait_event_freezekillable and havecifs use it
From: Steve French
Date: Thu Sep 29 2011 - 00:28:08 EST
The general idea of the patch seems like a good idea to
me. Assuming testing feedback was good from the problem
reporters, what tree would you want it merged from?
On Wed, Sep 28, 2011 at 6:52 AM, Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> CIFS currently uses wait_event_killable to put tasks to sleep while
> they await replies from the server. That function though does not
> allow the freezer to run. In many cases, the network interface may
> be going down anyway, in which case the reply will never come. The
> client then ends up blocking the computer from suspending.
>
> Fix this by adding a new wait_event_freezable variant --
> wait_event_freezekillable. The idea is to combine the behavior of
> wait_event_killable and wait_event_freezable -- put the task to
> sleep and only allow it to be awoken by fatal signals, but also
> allow the freezer to do its job.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/cifs/transport.c | 3 ++-
> include/linux/freezer.h | 19 +++++++++++++++++--
> 2 files changed, 19 insertions(+), 3 deletions(-)
>
> diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> index 10ca6b2..791bc4f 100644
> --- a/fs/cifs/transport.c
> +++ b/fs/cifs/transport.c
> @@ -26,6 +26,7 @@
> #include <linux/wait.h>
> #include <linux/net.h>
> #include <linux/delay.h>
> +#include <linux/freezer.h>
> #include <asm/uaccess.h>
> #include <asm/processor.h>
> #include <linux/mempool.h>
> @@ -324,7 +325,7 @@ wait_for_response(struct TCP_Server_Info *server, struct mid_q_entry *midQ)
> {
> int error;
>
> - error = wait_event_killable(server->response_q,
> + error = wait_event_freezekillable(server->response_q,
> midQ->midState != MID_REQUEST_SUBMITTED);
> if (error < 0)
> return -ERESTARTSYS;
> diff --git a/include/linux/freezer.h b/include/linux/freezer.h
> index 1effc8b..3672f73 100644
> --- a/include/linux/freezer.h
> +++ b/include/linux/freezer.h
> @@ -134,10 +134,25 @@ static inline void set_freezable_with_signal(void)
> }
>
> /*
> - * Freezer-friendly wrappers around wait_event_interruptible() and
> - * wait_event_interruptible_timeout(), originally defined in <linux/wait.h>
> + * Freezer-friendly wrappers around wait_event_interruptible(),
> + * wait_event_killable() and wait_event_interruptible_timeout(), originally
> + * defined in <linux/wait.h>
> */
>
> +#define wait_event_freezekillable(wq, condition) \
> +({ \
> + int __retval; \
> + do { \
> + __retval = wait_event_killable(wq, \
> + (condition) || freezing(current)); \
> + if (__retval && !freezing(current)) \
> + break; \
> + else if (!(condition)) \
> + __retval = -ERESTARTSYS; \
> + } while (try_to_freeze()); \
> + __retval; \
> +})
> +
> #define wait_event_freezable(wq, condition) \
> ({ \
> int __retval; \
> --
> 1.7.6.2
>
>
--
Thanks,
Steve
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