Commit c0cfc337 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

lib/stackdepot: Provide functions which operate on plain storage arrays 



The struct stack_trace indirection in the stack depot functions is a truly
pointless excercise which requires horrible code at the callsites.

Provide interfaces based on plain storage arrays.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Acked-by: default avatarAlexander Potapenko <glider@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: linux-mm@kvack.org
Cc: David Rientjes <rientjes@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: kasan-dev@googlegroups.com
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: iommu@lists.linux-foundation.org
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: David Sterba <dsterba@suse.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: linux-btrfs@vger.kernel.org
Cc: dm-devel@redhat.com
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: dri-devel@lists.freedesktop.org
Cc: David Airlie <airlied@linux.ie>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: linux-arch@vger.kernel.org
Link: https://lkml.kernel.org/r/20190425094801.414574828@linutronix.de
parent e9b98e16

include/linux/stackdepot.h

+4 −0
Original line number Diff line number Diff line
@@ -26,7 +26,11 @@ typedef u32 depot_stack_handle_t; 
struct stack_trace;



depot_stack_handle_t depot_save_stack(struct stack_trace *trace, gfp_t flags);

depot_stack_handle_t stack_depot_save(unsigned long *entries,

				      unsigned int nr_entries, gfp_t gfp_flags);



void depot_fetch_stack(depot_stack_handle_t handle, struct stack_trace *trace);

unsigned int stack_depot_fetch(depot_stack_handle_t handle,

			       unsigned long **entries);



#endif

lib/stackdepot.c

+51 −19
Original line number Diff line number Diff line
@@ -194,40 +194,60 @@ static inline struct stack_record *find_stack(struct stack_record *bucket, 
	return NULL;

}



void depot_fetch_stack(depot_stack_handle_t handle, struct stack_trace *trace)

/**

 * stack_depot_fetch - Fetch stack entries from a depot

 *

 * @handle:		Stack depot handle which was returned from

 *			stack_depot_save().

 * @entries:		Pointer to store the entries address

 *

 * Return: The number of trace entries for this depot.

 */

unsigned int stack_depot_fetch(depot_stack_handle_t handle,

			       unsigned long **entries)

{

	union handle_parts parts = { .handle = handle };

	void *slab = stack_slabs[parts.slabindex];

	size_t offset = parts.offset << STACK_ALLOC_ALIGN;

	struct stack_record *stack = slab + offset;



	trace->nr_entries = trace->max_entries = stack->size;

	trace->entries = stack->entries;

	trace->skip = 0;

	*entries = stack->entries;

	return stack->size;

}

EXPORT_SYMBOL_GPL(stack_depot_fetch);



void depot_fetch_stack(depot_stack_handle_t handle, struct stack_trace *trace)

{

	unsigned int nent = stack_depot_fetch(handle, &trace->entries);



	trace->max_entries = trace->nr_entries = nent;

}

EXPORT_SYMBOL_GPL(depot_fetch_stack);



/**

 * depot_save_stack - save stack in a stack depot.

 * @trace - the stacktrace to save.

 * @alloc_flags - flags for allocating additional memory if required.

 * stack_depot_save - Save a stack trace from an array

 *

 * @entries:		Pointer to storage array

 * @nr_entries:		Size of the storage array

 * @alloc_flags:	Allocation gfp flags

 *

 * Returns the handle of the stack struct stored in depot.

 * Return: The handle of the stack struct stored in depot

 */

depot_stack_handle_t depot_save_stack(struct stack_trace *trace,

depot_stack_handle_t stack_depot_save(unsigned long *entries,

				      unsigned int nr_entries,

				      gfp_t alloc_flags)

{

	u32 hash;

	depot_stack_handle_t retval = 0;

	struct stack_record *found = NULL, **bucket;

	unsigned long flags;

	depot_stack_handle_t retval = 0;

	struct page *page = NULL;

	void *prealloc = NULL;

	unsigned long flags;

	u32 hash;



	if (unlikely(trace->nr_entries == 0))

	if (unlikely(nr_entries == 0))

		goto fast_exit;



	hash = hash_stack(trace->entries, trace->nr_entries);

	hash = hash_stack(entries, nr_entries);

	bucket = &stack_table[hash & STACK_HASH_MASK];



	/*
@@ -235,8 +255,8 @@ depot_stack_handle_t depot_save_stack(struct stack_trace *trace, 
	 * The smp_load_acquire() here pairs with smp_store_release() to

	 * |bucket| below.

	 */

	found = find_stack(smp_load_acquire(bucket), trace->entries,

			   trace->nr_entries, hash);

	found = find_stack(smp_load_acquire(bucket), entries,

			   nr_entries, hash);

	if (found)

		goto exit;
@@ -264,10 +284,10 @@ depot_stack_handle_t depot_save_stack(struct stack_trace *trace, 


	spin_lock_irqsave(&depot_lock, flags);



	found = find_stack(*bucket, trace->entries, trace->nr_entries, hash);

	found = find_stack(*bucket, entries, nr_entries, hash);

	if (!found) {

		struct stack_record *new =

			depot_alloc_stack(trace->entries, trace->nr_entries,

			depot_alloc_stack(entries, nr_entries,

					  hash, &prealloc, alloc_flags);

		if (new) {

			new->next = *bucket;
@@ -297,4 +317,16 @@ exit: 
fast_exit:

	return retval;

}

EXPORT_SYMBOL_GPL(stack_depot_save);



/**

 * depot_save_stack - save stack in a stack depot.

 * @trace - the stacktrace to save.

 * @alloc_flags - flags for allocating additional memory if required.

 */

depot_stack_handle_t depot_save_stack(struct stack_trace *trace,

				      gfp_t alloc_flags)

{

	return stack_depot_save(trace->entries, trace->nr_entries, alloc_flags);

}

EXPORT_SYMBOL_GPL(depot_save_stack);

CRA Git | Maintained and supported by SUSTech CRA and CCSE