linux/net/core
Neil Horman bd7c4b604a netpoll: convert mutex into a semaphore
Bart Van Assche recently reported a warning to me:

<IRQ>  [<ffffffff8103d79f>] warn_slowpath_common+0x7f/0xc0
[<ffffffff8103d7fa>] warn_slowpath_null+0x1a/0x20
[<ffffffff814761dd>] mutex_trylock+0x16d/0x180
[<ffffffff813968c9>] netpoll_poll_dev+0x49/0xc30
[<ffffffff8136a2d2>] ? __alloc_skb+0x82/0x2a0
[<ffffffff81397715>] netpoll_send_skb_on_dev+0x265/0x410
[<ffffffff81397c5a>] netpoll_send_udp+0x28a/0x3a0
[<ffffffffa0541843>] ? write_msg+0x53/0x110 [netconsole]
[<ffffffffa05418bf>] write_msg+0xcf/0x110 [netconsole]
[<ffffffff8103eba1>] call_console_drivers.constprop.17+0xa1/0x1c0
[<ffffffff8103fb76>] console_unlock+0x2d6/0x450
[<ffffffff8104011e>] vprintk_emit+0x1ee/0x510
[<ffffffff8146f9f6>] printk+0x4d/0x4f
[<ffffffffa0004f1d>] scsi_print_command+0x7d/0xe0 [scsi_mod]

This resulted from my commit ca99ca14c which introduced a mutex_trylock
operation in a path that could execute in interrupt context.  When mutex
debugging is enabled, the above warns the user when we are in fact
exectuting in interrupt context
interrupt context.

After some discussion, It seems that a semaphore is the proper mechanism to use
here.  While mutexes are defined to be unusable in interrupt context, no such
condition exists for semaphores (save for the fact that the non blocking api
calls, like up and down_trylock must be used when in irq context).

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reported-by: Bart Van Assche <bvanassche@acm.org>
CC: Bart Van Assche <bvanassche@acm.org>
CC: David Miller <davem@davemloft.net>
CC: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-05-01 15:00:24 -04:00
..
datagram.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-04-30 03:55:20 -04:00
dev_addr_lists.c net: add dev_uc_sync_multiple() and dev_mc_sync_multiple() api 2013-04-15 16:10:47 -04:00
dev_ioctl.c net: move ioctl functions into a separated file 2013-02-18 12:27:32 -05:00
dev.c net: Use consume_skb() to free gso segmented skb 2013-04-30 00:18:13 -04:00
drop_monitor.c drop_monitor: dont sleep in atomic context 2012-06-04 11:42:01 -04:00
dst.c net: add skb_dst_set_noref_force 2013-04-02 00:22:53 +02:00
ethtool.c net: Add missing netdev feature strings for NETIF_F_HW_VLAN_STAG_* 2013-04-19 16:16:50 -04:00
fib_rules.c rtnetlink: Remove passing of attributes into rtnl_doit functions 2013-03-22 10:31:16 -04:00
filter.c filter: add ANC_PAY_OFFSET instruction for loading payload start offset 2013-03-20 13:15:45 -04:00
flow_dissector.c net: flow_dissector: add __skb_get_poff to get a start offset to payload 2013-03-20 13:15:45 -04:00
flow.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-04-01 13:36:50 -04:00
gen_estimator.c Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
gen_stats.c gen_stats: Stop using NLA_PUT*(). 2012-04-02 04:33:44 -04:00
iovec.c net: get rid of some pointless casts to sockaddr 2012-03-11 19:11:22 -07:00
link_watch.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2012-10-02 13:38:27 -07:00
Makefile net: move procfs code to net/core/net-procfs.c 2013-02-19 00:51:10 -05:00
neighbour.c neighbour: Convert NEIGH_PRINTK to neigh_dbg 2013-04-16 16:34:08 -04:00
net_namespace.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
net-procfs.c net: Print functions in /proc/net/ptype without the offset. 2013-03-25 14:12:55 -04:00
net-sysfs.c net/core: apply pm_runtime_set_memalloc_noio on network devices 2013-02-23 17:50:16 -08:00
net-sysfs.h xps: Add CONFIG_XPS 2010-11-28 18:24:14 -08:00
net-traces.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
netevent.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
netpoll.c netpoll: convert mutex into a semaphore 2013-05-01 15:00:24 -04:00
netprio_cgroup.c Revert "netprio_cgroup: make local table static" 2013-04-12 03:06:44 -04:00
pktgen.c net: proc: change proc_net_remove to remove_proc_entry 2013-02-18 14:53:08 -05:00
request_sock.c tcp: fix a panic on UP machines in reqsk_fastopen_remove 2013-01-14 18:10:05 -05:00
rtnetlink.c net: fix address check in rtnl_fdb_del 2013-04-25 04:14:08 -04:00
scm.c netprio_cgroup: remove task_struct parameter from sock_update_netprio() 2013-04-09 13:19:37 -04:00
secure_seq.c net: defer net_secret[] initialization 2013-04-29 15:14:02 -04:00
skbuff.c packet: tx timestamping on tpacket ring 2013-04-25 01:22:22 -04:00
sock_diag.c sock_diag: allow to dump bpf filters 2013-04-29 13:21:30 -04:00
sock.c netprio_cgroup: remove task_struct parameter from sock_update_netprio() 2013-04-09 13:19:37 -04:00
stream.c net: Fix the condition passed to sk_wait_event() 2010-10-03 20:41:32 -07:00
sysctl_net_core.c net: avoid to hang up on sending due to sysctl configuration overflow. 2013-01-28 23:15:27 -05:00
timestamping.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
user_dma.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
utils.c net: core: let's use native isxdigit instead of custom 2013-03-27 12:48:32 -04:00