x86/events/amd/iommu: Clean up perf_iommu_read()

Fix coding style and use GENMASK_ULL().

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Jörg Rödel <joro@8bytes.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: iommu@lists.linux-foundation.org
Link: http://lkml.kernel.org/r/1487926102-13073-4-git-send-email-Suravee.Suthikulpanit@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/events/amd/iommu.c b/arch/x86/events/amd/iommu.c
index e112f498a0197c3af457d5212ccbbef3d6066e2b..d4375dadd4e9ead03f30640de7a9f6d60c6a690d 100644 (file)
--- a/arch/x86/events/amd/iommu.c
+++ b/arch/x86/events/amd/iommu.c
@@ -320,9 +320,7 @@ static void perf_iommu_start(struct perf_event *event, int flags)
 
 static void perf_iommu_read(struct perf_event *event)
 {
-       u64 count = 0ULL;
-       u64 prev_raw_count = 0ULL;
-       u64 delta = 0ULL;
+       u64 count, prev, delta;
        struct hw_perf_event *hwc = &event->hw;
 
        amd_iommu_pc_get_set_reg_val(_GET_DEVID(event),
@@ -330,18 +328,16 @@ static void perf_iommu_read(struct perf_event *event)
                                IOMMU_PC_COUNTER_REG, &count, false);
 
        /* IOMMU pc counter register is only 48 bits */
-       count &= 0xFFFFFFFFFFFFULL;
+       count &= GENMASK_ULL(47, 0);
 
-       prev_raw_count =  local64_read(&hwc->prev_count);
-       if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
-                                       count) != prev_raw_count)
+       prev = local64_read(&hwc->prev_count);
+       if (local64_cmpxchg(&hwc->prev_count, prev, count) != prev)
                return;
 
-       /* Handling 48-bit counter overflowing */
-       delta = (count << COUNTER_SHIFT) - (prev_raw_count << COUNTER_SHIFT);
+       /* Handle 48-bit counter overflow */
+       delta = (count << COUNTER_SHIFT) - (prev << COUNTER_SHIFT);
        delta >>= COUNTER_SHIFT;
        local64_add(delta, &event->count);
-
 }
 
 static void perf_iommu_stop(struct perf_event *event, int flags)