From b65c2045cc5089bd3cfacc9fad63798fded64226 Mon Sep 17 00:00:00 2001 From: Grzegorz Morys Date: Mon, 9 Oct 2017 12:38:04 -0700 Subject: [PATCH] IB/hfi1: Correct unnecessary acquisition of HW mutex Avoid acquiring already acquired hardware mutex and releasing the unacquired one as these are redundant operations. Add printouts for such situations to help detect potential errors within the driver. Reviewed-by: Mike Marciniszyn Signed-off-by: Grzegorz Morys Signed-off-by: Dennis Dalessandro Signed-off-by: Doug Ledford --- drivers/infiniband/hw/hfi1/firmware.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/drivers/infiniband/hw/hfi1/firmware.c b/drivers/infiniband/hw/hfi1/firmware.c index 001698b744ee..cea0d4f3248f 100644 --- a/drivers/infiniband/hw/hfi1/firmware.c +++ b/drivers/infiniband/hw/hfi1/firmware.c @@ -1387,7 +1387,14 @@ int acquire_hw_mutex(struct hfi1_devdata *dd) unsigned long timeout; int try = 0; u8 mask = 1 << dd->hfi1_id; - u8 user; + u8 user = (u8)read_csr(dd, ASIC_CFG_MUTEX); + + if (user == mask) { + dd_dev_info(dd, + "Hardware mutex already acquired, mutex mask %u\n", + (u32)mask); + return 0; + } retry: timeout = msecs_to_jiffies(HM_TIMEOUT) + jiffies; @@ -1418,7 +1425,15 @@ retry: void release_hw_mutex(struct hfi1_devdata *dd) { - write_csr(dd, ASIC_CFG_MUTEX, 0); + u8 mask = 1 << dd->hfi1_id; + u8 user = (u8)read_csr(dd, ASIC_CFG_MUTEX); + + if (user != mask) + dd_dev_warn(dd, + "Unable to release hardware mutex, mutex mask %u, my mask %u\n", + (u32)user, (u32)mask); + else + write_csr(dd, ASIC_CFG_MUTEX, 0); } /* return the given resource bit(s) as a mask for the given HFI */ -- 2.30.2