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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 <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jakub Kicinski 2017-05-28 17:53:01 -07:00 committed by David S. Miller
parent eefbde7e10
commit 9b5655767c
3 changed files with 20 additions and 4 deletions
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5
drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cpp.h
View File

@ -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;

9
drivers/net/ethernet/netronome/nfp/nfpcore/nfp_mutex.c
View File

@ -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;

10
drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c
View File

@ -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);