linux-toradex.git/drivers/block/nbd.c, branch v4.3 Linux kernel for Apalis and Colibri modules nbd: Add locking for tasks 2015-10-08T20:21:24+00:00 Markus Pargmann mpa@pengutronix.de 2015-10-06T18:03:54+00:00 dcc909d90ccdbb73226397ff6d298f7af35b0e11 The timeout handling introduced in 7e2893a16d3e (nbd: Fix timeout detection) introduces a race condition which may lead to killing of tasks that are not in nbd context anymore. This was not observed or reproducable yet. This patch adds locking to critical use of task_recv and task_send to avoid killing tasks that already left the NBD thread functions. This lock is only acquired if a timeout occures or the nbd device starts/stops. Reported-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Markus Pargmann <mpa@pengutronix.de> Reviewed-by: Ben Hutchings <ben@decadent.org.uk> Fixes: 7e2893a16d3e ("nbd: Fix timeout detection") Signed-off-by: Jens Axboe <axboe@fb.com> 
The timeout handling introduced in
	7e2893a16d3e (nbd: Fix timeout detection)
introduces a race condition which may lead to killing of tasks that are
not in nbd context anymore. This was not observed or reproducable yet.

This patch adds locking to critical use of task_recv and task_send to
avoid killing tasks that already left the NBD thread functions. This
lock is only acquired if a timeout occures or the nbd device
starts/stops.

Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Reviewed-by: Ben Hutchings <ben@decadent.org.uk>
Fixes: 7e2893a16d3e ("nbd: Fix timeout detection")
Signed-off-by: Jens Axboe <axboe@fb.com>
nbd: flags is a u32 variable 2015-08-17T14:23:01+00:00 Markus Pargmann mpa@pengutronix.de 2015-08-17T06:20:09+00:00 22d109c1bb312dbf321f3d0ab1b0ed94f1a7e304 The flags variable is used as u32 variable. This patch changes the type to be u32. Signed-off-by: Markus Pargmann <mpa@pengutronix.de> Signed-off-by: Jens Axboe <axboe@fb.com> 
The flags variable is used as u32 variable. This patch changes the type
to be u32.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
nbd: Rename functions for clearness of recv/send path 2015-08-17T14:22:59+00:00 Markus Pargmann mpa@pengutronix.de 2015-08-17T06:20:08+00:00 cad73b2703cff68b140d68221eeecd5a30322b44 This patch renames functions so that it is clear what the function does. Otherwise it is not directly understandable what for example 'do_it' means. Signed-off-by: Markus Pargmann <mpa@pengutronix.de> Signed-off-by: Jens Axboe <axboe@fb.com> 
This patch renames functions so that it is clear what the function does.
Otherwise it is not directly understandable what for example 'do_it' means.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
nbd: Change 'disconnect' to be boolean 2015-08-17T14:22:58+00:00 Markus Pargmann mpa@pengutronix.de 2015-08-17T06:20:07+00:00 696697cb50e4b57d4163d59a496ad9e52f6bff8a Signed-off-by: Markus Pargmann <mpa@pengutronix.de> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Jens Axboe <axboe@fb.com> 
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Acked-by: Pavel Machek  <pavel@ucw.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
nbd: Add debugfs entries 2015-08-17T14:22:56+00:00 Markus Pargmann mpa@pengutronix.de 2015-08-17T06:20:06+00:00 30d53d9c11b6c2f71253a2be582969d7e6fa7f10 Add some debugfs files that help to understand the internal state of NBD. This exports the different sizes, flags, tasks and so on. Signed-off-by: Markus Pargmann <mpa@pengutronix.de> Signed-off-by: Jens Axboe <axboe@fb.com> 
Add some debugfs files that help to understand the internal state of
NBD. This exports the different sizes, flags, tasks and so on.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
nbd: Remove variable 'pid' 2015-08-17T14:22:55+00:00 Markus Pargmann mpa@pengutronix.de 2015-08-17T06:20:05+00:00 6521d39a64b3f9c3acb0fd25a34cfaf9a40e548e This patch uses nbd->task_recv to determine the value of the previously used variable 'pid' for sysfs. Signed-off-by: Markus Pargmann <mpa@pengutronix.de> Signed-off-by: Jens Axboe <axboe@fb.com> 
This patch uses nbd->task_recv to determine the value of the previously
used variable 'pid' for sysfs.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
nbd: Move clear queue debug message 2015-08-17T14:22:53+00:00 Markus Pargmann mpa@pengutronix.de 2015-08-17T06:20:04+00:00 e78273c80b213806ec7c51176ec81e034fe5cb9f This message was a warning without a reason. This patch moves it into nbd_clear_que and transforms it to a debug message. Signed-off-by: Markus Pargmann <mpa@pengutronix.de> Signed-off-by: Jens Axboe <axboe@fb.com> 
This message was a warning without a reason. This patch moves it into
nbd_clear_que and transforms it to a debug message.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
nbd: Remove 'harderror' and propagate error properly 2015-08-17T14:22:52+00:00 Markus Pargmann mpa@pengutronix.de 2015-08-17T06:20:03+00:00 193918307f4e66eb6a811f30795991c6f7680b34 Instead of a variable 'harderror' we can simply try to correctly propagate errors to the userspace. This patch removes the harderror variable and passes errors through error pointers and nbd_do_it back to the userspace. Signed-off-by: Markus Pargmann <mpa@pengutronix.de> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Jens Axboe <axboe@fb.com> 
Instead of a variable 'harderror' we can simply try to correctly
propagate errors to the userspace.

This patch removes the harderror variable and passes errors through
error pointers and nbd_do_it back to the userspace.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
nbd: restructure sock_shutdown 2015-08-17T14:22:50+00:00 Markus Pargmann mpa@pengutronix.de 2015-08-17T06:20:02+00:00 260bbce403e2ac601b422fd926f48b9924051f92 This patch restructures sock_shutdown to avoid having the main code path in an if block. Signed-off-by: Markus Pargmann <mpa@pengutronix.de> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Jens Axboe <axboe@fb.com> 
This patch restructures sock_shutdown to avoid having the main code path
in an if block.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
nbd: sock_shutdown, remove conditional lock 2015-08-17T14:22:49+00:00 Markus Pargmann mpa@pengutronix.de 2015-08-17T06:20:01+00:00 36e47bee7c9bc7771aad6e972dea92e2324338a4 Move the conditional lock from sock_shutdown into the surrounding code. Signed-off-by: Markus Pargmann <mpa@pengutronix.de> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Jens Axboe <axboe@fb.com> 
Move the conditional lock from sock_shutdown into the surrounding code.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>