-
Steffen Maier authored
commit 9edf7d75 upstream. Commit 64deb6ef "[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 8d88cf3f "[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> Signed-off-by: James Bottomley <JBottomley@Parallels.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
8f425c63