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
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acpi
asm-generic
clocksource
crypto
drm
keys
linux	netpoll: convert mutex into a semaphore	2013-05-01 15:00:24 -04:00
math-emu
media
memory
misc
net	Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next into for-davem	2013-04-29 15:31:57 -04:00
pcmcia
ras
rdma
rxrpc
scsi
sound
target
trace
uapi	net: Add MIB counters for checksum errors	2013-04-29 15:14:03 -04:00
video
xen
Kbuild