Steffen Maier 9edf7d75ee [SCSI] zfcp: status read buffers on first adapter open with link down ... Commit 64deb6efdc "[SCSI] zfcp: Use status_read_buf_num provided by FCP channel" started using a value returned by the channel but only evaluated the value if the fabric link is up. Commit 8d88cf3f3b "[SCSI] zfcp: Update status read mempool" introduced mempool resizings based on the above value. On setting an FCP device online for the very first time since boot, a new zeroed adapter object is allocated. If the link is down, the number of status read requests remains zero. Since just the config data exchange is incomplete, we proceed with adapter open recovery. However, we unconditionally call mempool_resize with adapter->stat_read_buf_num == 0 in this case. This causes a kernel message "kernel BUG at mm/mempool.c:131!" in process "zfcperp<FCP-device-bus-ID>" with last function mempool_resize in Krnl PSW and zfcp_erp_thread in the Call Trace. Don't evaluate channel values which are invalid on link down. The number of status read requests is always valid, evaluated, and set to a positive minimum greater than zero. The adapter open recovery can proceed and the channel has status read buffers to inform us on a future link up event. While we are not aware of any other code path that could result in mempool resize attempts of size zero, we still also initialize the number of status read buffers to be posted to a static minimum number on adapter object allocation. Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> #2.6.35+ Signed-off-by: James Bottomley <JBottomley@Parallels.com>		2013-05-31 16:32:38 -07:00
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block	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux	2013-05-21 09:36:46 -07:00
char	s390/memory hotplug,sclp: get rid of per memory increment usecount	2013-05-02 15:50:28 +02:00
cio	s390/cio: add channel ID sysfs attribute	2013-05-15 16:47:39 +02:00
crypto	s390/zcrypt: ap bus rescan problem when toggle crypto adapters on/off	2013-05-02 17:10:20 +02:00
kvm	Merge tag 'kvm-3.10-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm	2013-05-05 14:47:31 -07:00
net	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2013-04-22 20:32:51 -04:00
scsi	[SCSI] zfcp: status read buffers on first adapter open with link down	2013-05-31 16:32:38 -07:00
Makefile	[S390] split/move machine check handler code	2009-03-26 15:24:10 +01:00