https://github.com/torvalds/linux
Revision 10a214dc996236e6547b84fb5ca007316b30c2e6 authored by Devesh Sharma on 24 December 2015, 18:14:07 UTC, committed by Doug Ledford on 28 December 2015, 16:45:54 UTC
Recently Dough Ledford reported a deadlock happening between ocrdma-load sequence and NetworkManager service issuing "open" on be2net interface. The deadlock happens when any be2net hook (e.g. open/close) is called in parallel to insmod ocrdma.ko. A. be2net is sending administrative open/close event to ocrdma holding device_list_mutex. It does this from ndo_open/ndo_stop hooks of be2net. So sequence of locks is rtnl_lock---> device_list lock B. When new ocrdma roce device gets registered, infiniband stack now takes rtnl_lock in ib_register_device() in GID initialization routines. So sequence of locks in this path is device_list lock ---> rtnl_lock. This improper locking sequence causes deadlock. With this patch we stop using administrative open and close events injected by be2net driver. These events were used to dispatch PORT_ACTIVE and PORT_ERROR events to the IB-stack. This patch implements a logic to receive async-link-events generated from CNA whenever link-state-change is detected. Now on, these async-events will be used to dispatch PORT_ACTIVE and PORT_ERROR events to IB-stack. Depending on async-events from CNA removes the need to hold device-list-mutex and thus breaks the busy-wait scenario. Reported-by: Doug Ledford <dledford@redhat.com> CC: Sathya Perla <sathya.perla@avagotech.com> Signed-off-by: Padmanabh Ratnakar <padmanabh.ratnakar@avagotech.com> Signed-off-by: Selvin Xavier <selvin.xavier@avagotech.com> Signed-off-by: Devesh Sharma <devesh.sharma@avagotech.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
1 parent 36ac0db
Tip revision: 10a214dc996236e6547b84fb5ca007316b30c2e6 authored by Devesh Sharma on 24 December 2015, 18:14:07 UTC
RDMA/ocrdma: Depend on async link events from CNA
RDMA/ocrdma: Depend on async link events from CNA
Tip revision: 10a214d
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COPYING | -rw-r--r-- | 18.3 KB |
CREDITS | -rw-r--r-- | 94.9 KB |
Kbuild | -rw-r--r-- | 2.6 KB |
Kconfig | -rw-r--r-- | 252 bytes |
MAINTAINERS | -rw-r--r-- | 328.5 KB |
Makefile | -rw-r--r-- | 53.5 KB |
README | -rw-r--r-- | 18.2 KB |
REPORTING-BUGS | -rw-r--r-- | 7.3 KB |
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