[PATCH net-next 09/12] nfp: don't wait for resources indefinitely
From: Jakub Kicinski <hidden>
Date: 2017-05-28 00:34:49
Subsystem:
netronome ethernet drivers, networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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 <redacted> --- drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cpp.h | 5 +++++ drivers/net/ethernet/netronome/nfp/nfpcore/nfp_mutex.c | 9 +++++++-- drivers/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 @@ nfp_resource_try_acquire(struct nfp_cpp *cpp, struct nfp_resource *res, 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);
--
2.11.0