x86, UV: Remove BAU check for stay-busy

Remove a faulty assumption that a long running BAU request has
encountered a hardware problem and will never finish.

Numalink congestion can make a request appear to have
encountered such a problem, but it is not safe to cancel the
request.  If such a cancel is done but a reply is later received
we can miss a TLB shootdown.

We depend upon the max_bau_concurrent 'throttle' to prevent the
stay-busy case from happening.

Signed-off-by: Cliff Wickman <cpw@sgi.com>
Cc: gregkh@suse.de
LKML-Reference: <E1OJvNy-0004ad-BV@eag09.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 0 insertions, 24 deletions

diff --git a/arch/x86/include/asm/uv/uv_bau.h b/arch/x86/include/asm/uv/uv_bau.h
index 1c8f1e9bf74f..c19b870ea58a 100644
--- a/arch/x86/include/asm/uv/uv_bau.h
+++ b/arch/x86/include/asm/uv/uv_bau.h
@@ -402,7 +402,6 @@ struct bau_control {
         unsigned short uvhub_quiesce;
         short socket_acknowledge_count[DEST_Q_SIZE];
         cycles_t send_message;
-        spinlock_t masks_lock;
         spinlock_t uvhub_lock;
         spinlock_t queue_lock;
         /* tunables */
diff --git a/arch/x86/kernel/tlb_uv.c b/arch/x86/kernel/tlb_uv.c
index ab929e976502..dc962b5ac870 100644
--- a/arch/x86/kernel/tlb_uv.c
+++ b/arch/x86/kernel/tlb_uv.c
@@ -405,12 +405,10 @@ static int uv_wait_completion(struct bau_desc *bau_desc,
         unsigned long mmr;
         unsigned long mask;
         cycles_t ttime;
-        cycles_t timeout_time;
         struct ptc_stats *stat = bcp->statp;
         struct bau_control *hmaster;
 
         hmaster = bcp->uvhub_master;
-        timeout_time = get_cycles() + bcp->timeout_interval;
 
         /* spin on the status MMR, waiting for it to go idle */
         while ((descriptor_status = (((unsigned long)
@@ -450,26 +448,6 @@ static int uv_wait_completion(struct bau_desc *bau_desc,
                          * descriptor_status is still BUSY
                          */
                         cpu_relax();
-                        relaxes++;
-                        if (relaxes >= 10000) {
-                                relaxes = 0;
-                                if (get_cycles() > timeout_time) {
-                                        quiesce_local_uvhub(hmaster);
-
-                                        /* single-thread the register change */
-                                        spin_lock(&hmaster->masks_lock);
-                                        mmr = uv_read_local_mmr(mmr_offset);
-                                        mask = 0UL;
-                                        mask |= (3UL < right_shift);
-                                        mask = ~mask;
-                                        mmr &= mask;
-                                        uv_write_local_mmr(mmr_offset, mmr);
-                                        spin_unlock(&hmaster->masks_lock);
-                                        end_uvhub_quiesce(hmaster);
-                                        stat->s_busy++;
-                                        return FLUSH_GIVEUP;
-                                }
-                        }
                 }
         }
         bcp->conseccompletes++;
@@ -1580,7 +1558,6 @@ static void uv_init_per_cpu(int nuvhubs)
         for_each_present_cpu(cpu) {
                 bcp = &per_cpu(bau_control, cpu);
                 memset(bcp, 0, sizeof(struct bau_control));
-                spin_lock_init(&bcp->masks_lock);
                 pnode = uv_cpu_hub_info(cpu)->pnode;
                 uvhub = uv_cpu_hub_info(cpu)->numa_blade_id;
                 uvhub_mask |= (1 << uvhub);