From 9b5655767c6763f0322d8292f3d9dbc43816d22e Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Sun, 28 May 2017 17:53:01 -0700 Subject: [PATCH] nfp: don't wait for resources indefinitely There is currently no timeout to the resource and lock acquiring loops. We printed warnings and depended on user sending a signal to the waiting process to stop the waiting. This doesn't work very well when wait happens out of a work queue. The simplest example of that is PCI probe. When user loads the module and card is in a broken state modprobe will wait forever and signals sent to it will not actually reach the probing thread. Make sure all wait loops have a time out. Set the upper wait time to 60 seconds to stay on the safe side. Signed-off-by: Jakub Kicinski Signed-off-by: David S. Miller --- drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cpp.h | 5 +++++ drivers/net/ethernet/netronome/nfp/nfpcore/nfp_mutex.c | 9 +++++++-- .../net/ethernet/netronome/nfp/nfpcore/nfp_resource.c | 10 ++++++++-- 3 files changed, 20 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cpp.h b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cpp.h index 8d46b9acb69f..0a46c0984e68 100644 --- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cpp.h +++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cpp.h @@ -63,6 +63,11 @@ /* Max size of area it should be safe to request */ #define NFP_CPP_SAFE_AREA_SIZE SZ_2M +/* NFP_MUTEX_WAIT_* are timeouts in seconds when waiting for a mutex */ +#define NFP_MUTEX_WAIT_FIRST_WARN 15 +#define NFP_MUTEX_WAIT_NEXT_WARN 5 +#define NFP_MUTEX_WAIT_ERROR 60 + struct device; struct nfp_cpp_area; diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_mutex.c b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_mutex.c index 8a99c189efa8..f7b958181126 100644 --- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_mutex.c +++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_mutex.c @@ -195,7 +195,8 @@ void nfp_cpp_mutex_free(struct nfp_cpp_mutex *mutex) */ int nfp_cpp_mutex_lock(struct nfp_cpp_mutex *mutex) { - unsigned long warn_at = jiffies + 15 * HZ; + unsigned long warn_at = jiffies + NFP_MUTEX_WAIT_FIRST_WARN * HZ; + unsigned long err_at = jiffies + NFP_MUTEX_WAIT_ERROR * HZ; unsigned int timeout_ms = 1; int err; @@ -214,12 +215,16 @@ int nfp_cpp_mutex_lock(struct nfp_cpp_mutex *mutex) return -ERESTARTSYS; if (time_is_before_eq_jiffies(warn_at)) { - warn_at = jiffies + 60 * HZ; + warn_at = jiffies + NFP_MUTEX_WAIT_NEXT_WARN * HZ; nfp_warn(mutex->cpp, "Warning: waiting for NFP mutex [depth:%hd target:%d addr:%llx key:%08x]\n", mutex->depth, mutex->target, mutex->address, mutex->key); } + if (time_is_before_eq_jiffies(err_at)) { + nfp_err(mutex->cpp, "Error: mutex wait timed out\n"); + return -EBUSY; + } } return err; diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c index 2d15a7c9d0de..072612263dab 100644 --- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c +++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c @@ -181,7 +181,8 @@ err_unlock_dev: struct nfp_resource * nfp_resource_acquire(struct nfp_cpp *cpp, const char *name) { - unsigned long warn_at = jiffies + 15 * HZ; + unsigned long warn_at = jiffies + NFP_MUTEX_WAIT_FIRST_WARN * HZ; + unsigned long err_at = jiffies + NFP_MUTEX_WAIT_ERROR * HZ; struct nfp_cpp_mutex *dev_mutex; struct nfp_resource *res; int err; @@ -214,10 +215,15 @@ nfp_resource_acquire(struct nfp_cpp *cpp, const char *name) } if (time_is_before_eq_jiffies(warn_at)) { - warn_at = jiffies + 60 * HZ; + warn_at = jiffies + NFP_MUTEX_WAIT_NEXT_WARN * HZ; nfp_warn(cpp, "Warning: waiting for NFP resource %s\n", name); } + if (time_is_before_eq_jiffies(err_at)) { + nfp_err(cpp, "Error: resource %s timed out\n", name); + err = -EBUSY; + goto err_free; + } } nfp_cpp_mutex_free(dev_mutex); -- 2.20.1