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
..
acpi	Fixes:	2013-03-12 20:25:53 -07:00
asm-generic	x86-32: Fix possible incomplete TLB invalidate with PAE pagetables	2013-04-12 16:56:47 -07:00
clocksource	ImgTec Meta architecture changes for v3.9-rc1	2013-03-03 12:06:09 -08:00
crypto
drm	drm/radeon: add Richland pci ids	2013-03-15 18:47:19 -04:00
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	libfc, fcoe, bnx2fc: Split fc_disc_init into fc_disc_{init, config}	2013-03-25 16:03:03 -07:00
sound	Merge remote-tracking branch 'asoc/fix/max98090' into asoc-next	2013-03-26 14:08:03 +00:00
target	target: Rename spc_get_write_same_sectors -> sbc_get_write_same_sectors	2013-02-23 12:46:14 -08:00
trace	Revert "block: add missing block_bio_complete() tracepoint"	2013-04-18 09:00:26 -07:00
uapi	net: Add MIB counters for checksum errors	2013-04-29 15:14:03 -04:00
video	ARM: at91: fix LCD-wiring mode	2013-03-13 11:05:04 +01:00
xen	xen-netback: coalesce slots in TX path and fix regressions	2013-04-22 15:37:01 -04:00
Kbuild