[tip:core/stacktrace] drm: Simplify stacktrace handling

From: tip-bot for Thomas Gleixner
Date: Mon Apr 29 2019 - 14:43:19 EST


Commit-ID: 487f3c7fb1a07ceff78bb18688eb8538a4775227
Gitweb: https://git.kernel.org/tip/487f3c7fb1a07ceff78bb18688eb8538a4775227
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Thu, 25 Apr 2019 11:45:09 +0200
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Mon, 29 Apr 2019 12:37:53 +0200

drm: Simplify stacktrace handling

Replace the indirection through struct stack_trace by using the storage
array based interfaces.

The original code in all printing functions is really wrong. It allocates a
storage array on stack which is unused because depot_fetch_stack() does not
store anything in it. It overwrites the entries pointer in the stack_trace
struct so it points to the depot storage.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Acked-by: Daniel Vetter <daniel@xxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: David Airlie <airlied@xxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: kasan-dev@xxxxxxxxxxxxxxxx
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx
Cc: Robin Murphy <robin.murphy@xxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Johannes Thumshirn <jthumshirn@xxxxxxx>
Cc: David Sterba <dsterba@xxxxxxxx>
Cc: Chris Mason <clm@xxxxxx>
Cc: Josef Bacik <josef@xxxxxxxxxxxxxx>
Cc: linux-btrfs@xxxxxxxxxxxxxxx
Cc: dm-devel@xxxxxxxxxx
Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
Cc: Alasdair Kergon <agk@xxxxxxxxxx>
Cc: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
Cc: Miroslav Benes <mbenes@xxxxxxx>
Cc: linux-arch@xxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20190425094802.622094226@xxxxxxxxxxxxx

---
drivers/gpu/drm/drm_mm.c | 22 +++++++---------------
drivers/gpu/drm/i915/i915_vma.c | 11 ++++-------
drivers/gpu/drm/i915/intel_runtime_pm.c | 21 +++++++--------------
3 files changed, 18 insertions(+), 36 deletions(-)

diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index 69552777e13a..8b4cd31ce7bd 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -106,22 +106,19 @@
static noinline void save_stack(struct drm_mm_node *node)
{
unsigned long entries[STACKDEPTH];
- struct stack_trace trace = {
- .entries = entries,
- .max_entries = STACKDEPTH,
- .skip = 1
- };
+ unsigned int n;

- save_stack_trace(&trace);
+ n = stack_trace_save(entries, ARRAY_SIZE(entries), 1);

/* May be called under spinlock, so avoid sleeping */
- node->stack = depot_save_stack(&trace, GFP_NOWAIT);
+ node->stack = stack_depot_save(entries, n, GFP_NOWAIT);
}

static void show_leaks(struct drm_mm *mm)
{
struct drm_mm_node *node;
- unsigned long entries[STACKDEPTH];
+ unsigned long *entries;
+ unsigned int nr_entries;
char *buf;

buf = kmalloc(BUFSZ, GFP_KERNEL);
@@ -129,19 +126,14 @@ static void show_leaks(struct drm_mm *mm)
return;

list_for_each_entry(node, drm_mm_nodes(mm), node_list) {
- struct stack_trace trace = {
- .entries = entries,
- .max_entries = STACKDEPTH
- };
-
if (!node->stack) {
DRM_ERROR("node [%08llx + %08llx]: unknown owner\n",
node->start, node->size);
continue;
}

- depot_fetch_stack(node->stack, &trace);
- snprint_stack_trace(buf, BUFSZ, &trace, 0);
+ nr_entries = stack_depot_fetch(node->stack, &entries);
+ stack_trace_snprint(buf, BUFSZ, entries, nr_entries, 0);
DRM_ERROR("node [%08llx + %08llx]: inserted at\n%s",
node->start, node->size, buf);
}
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index b713bed20c38..41b5bcb803cb 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -36,11 +36,8 @@

static void vma_print_allocator(struct i915_vma *vma, const char *reason)
{
- unsigned long entries[12];
- struct stack_trace trace = {
- .entries = entries,
- .max_entries = ARRAY_SIZE(entries),
- };
+ unsigned long *entries;
+ unsigned int nr_entries;
char buf[512];

if (!vma->node.stack) {
@@ -49,8 +46,8 @@ static void vma_print_allocator(struct i915_vma *vma, const char *reason)
return;
}

- depot_fetch_stack(vma->node.stack, &trace);
- snprint_stack_trace(buf, sizeof(buf), &trace, 0);
+ nr_entries = stack_depot_fetch(vma->node.stack, &entries);
+ stack_trace_snprint(buf, sizeof(buf), entries, nr_entries, 0);
DRM_DEBUG_DRIVER("vma.node [%08llx + %08llx] %s: inserted at %s\n",
vma->node.start, vma->node.size, reason, buf);
}
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 1f8acbb332c9..20c4434474e3 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -60,27 +60,20 @@
static noinline depot_stack_handle_t __save_depot_stack(void)
{
unsigned long entries[STACKDEPTH];
- struct stack_trace trace = {
- .entries = entries,
- .max_entries = ARRAY_SIZE(entries),
- .skip = 1,
- };
+ unsigned int n;

- save_stack_trace(&trace);
- return depot_save_stack(&trace, GFP_NOWAIT | __GFP_NOWARN);
+ n = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
+ return stack_depot_save(entries, n, GFP_NOWAIT | __GFP_NOWARN);
}

static void __print_depot_stack(depot_stack_handle_t stack,
char *buf, int sz, int indent)
{
- unsigned long entries[STACKDEPTH];
- struct stack_trace trace = {
- .entries = entries,
- .max_entries = ARRAY_SIZE(entries),
- };
+ unsigned long *entries;
+ unsigned int nr_entries;

- depot_fetch_stack(stack, &trace);
- snprint_stack_trace(buf, sz, &trace, indent);
+ nr_entries = stack_depot_fetch(stack, &entries);
+ stack_trace_snprint(buf, sz, entries, nr_entries, indent);
}

static void init_intel_runtime_pm_wakeref(struct drm_i915_private *i915)