From: Jakub Kicinski Date: Wed, 22 Mar 2017 00:59:07 +0000 (-0700) Subject: nfp: disallow sharing mutexes on the same machine X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=3d4fc6eb4bc15cd81a150b065494f0e67d2493c0;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git nfp: disallow sharing mutexes on the same machine NFP can be connected to multiple machines via PCI or other buses. Access to hardware resources is arbitrated using locks residing in device memory. Currently nfpcore only respects the mutexes when it comes to inter-host locking, but if we try to acquire the same lock again, on one host - it will simply return success because owner of the lock is already set to that host. This makes the locks useless for arbitration within one host and unfair because whichever host grabbed the lock will have a chance to reacquire it without others getting a shot. Signed-off-by: Jakub Kicinski Signed-off-by: David S. Miller --- diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c index 40108e66c654..e2267b421af0 100644 --- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c +++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c @@ -1736,11 +1736,5 @@ int nfp_cpp_mutex_trylock(struct nfp_cpp_mutex *mutex) return 0; } - /* Already locked by us? Success! */ - if (tmp == value) { - mutex->depth = 1; - return 0; - } - return nfp_mutex_is_locked(tmp) ? -EBUSY : -EINVAL; }