[PATCH 11/12] IB/ehca: Serialize MR alloc and MR free hvCalls

From: Joachim Fenkes
Date: Tue Sep 11 2007 - 09:36:26 EST


Some firmware levels exhibit a race condition between H_ALLOC_RESOURCE(MR)
and H_FREE_RESOURCE(MR). Work around this problem by locking these hvCalls
against each other.

Signed-off-by: Joachim Fenkes <fenkes@xxxxxxxxxx>
---
drivers/infiniband/hw/ehca/hcp_if.c | 28 +++++++++++++++++++++-------
1 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/drivers/infiniband/hw/ehca/hcp_if.c b/drivers/infiniband/hw/ehca/hcp_if.c
index a70a5ed..d3d1ef2 100644
--- a/drivers/infiniband/hw/ehca/hcp_if.c
+++ b/drivers/infiniband/hw/ehca/hcp_if.c
@@ -120,15 +120,28 @@ static long ehca_plpar_hcall_norets(unsigned long opcode,
unsigned long arg7)
{
long ret;
- int i, sleep_msecs;
+ int i, sleep_msecs, do_lock;
+ unsigned long flags;

ehca_gen_dbg("opcode=%lx " HCALL7_REGS_FORMAT,
opcode, arg1, arg2, arg3, arg4, arg5, arg6, arg7);

+ /* lock H_FREE_RESOURCE(MR) against itself and H_ALLOC_RESOURCE(MR) */
+ if ((opcode == H_FREE_RESOURCE) && (arg7 == 5)) {
+ arg7 = 0; /* better not upset firmware */
+ do_lock = 1;
+ }
+
for (i = 0; i < 5; i++) {
+ if (do_lock)
+ spin_lock_irqsave(&hcall_lock, flags);
+
ret = plpar_hcall_norets(opcode, arg1, arg2, arg3, arg4,
arg5, arg6, arg7);

+ if (do_lock)
+ spin_unlock_irqrestore(&hcall_lock, flags);
+
if (H_IS_LONG_BUSY(ret)) {
sleep_msecs = get_longbusy_msecs(ret);
msleep_interruptible(sleep_msecs);
@@ -161,23 +174,24 @@ static long ehca_plpar_hcall9(unsigned long opcode,
unsigned long arg9)
{
long ret;
- int i, sleep_msecs, lock_is_set = 0;
+ int i, sleep_msecs, do_lock;
unsigned long flags = 0;

ehca_gen_dbg("INPUT -- opcode=%lx " HCALL9_REGS_FORMAT, opcode,
arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9);

+ /* lock H_ALLOC_RESOURCE(MR) against itself and H_FREE_RESOURCE(MR) */
+ do_lock = ((opcode == H_ALLOC_RESOURCE) && (arg2 == 5));
+
for (i = 0; i < 5; i++) {
- if ((opcode == H_ALLOC_RESOURCE) && (arg2 == 5)) {
+ if (do_lock)
spin_lock_irqsave(&hcall_lock, flags);
- lock_is_set = 1;
- }

ret = plpar_hcall9(opcode, outs,
arg1, arg2, arg3, arg4, arg5,
arg6, arg7, arg8, arg9);

- if (lock_is_set)
+ if (do_lock)
spin_unlock_irqrestore(&hcall_lock, flags);

if (H_IS_LONG_BUSY(ret)) {
@@ -807,7 +821,7 @@ u64 hipz_h_free_resource_mr(const struct ipz_adapter_handle adapter_handle,
return ehca_plpar_hcall_norets(H_FREE_RESOURCE,
adapter_handle.handle, /* r4 */
mr->ipz_mr_handle.handle, /* r5 */
- 0, 0, 0, 0, 0);
+ 0, 0, 0, 0, 5);
}

u64 hipz_h_reregister_pmr(const struct ipz_adapter_handle adapter_handle,
--
1.5.2


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