251 lines
6.4 KiB
Diff
251 lines
6.4 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Alexander Shishkin <alexander.shishkin@linux.intel.com>
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Date: Fri, 5 Oct 2018 15:43:05 +0300
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Subject: [PATCH] lib: Add memcat_p(): paste 2 pointer arrays together
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This adds a helper to paste 2 pointer arrays together, useful for merging
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various types of attribute arrays. There are a few places in the kernel
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tree where this is open coded, and I just added one more in the STM class.
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The naming is inspired by memset_p() and memcat(), and partial credit for
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it goes to Andy Shevchenko.
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This patch adds the function wrapped in a type-enforcing macro and a test
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module.
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Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
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Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
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Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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---
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include/linux/string.h | 7 +++
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lib/Kconfig.debug | 8 +++
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lib/Makefile | 1 +
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lib/string.c | 31 +++++++++++
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lib/test_memcat_p.c | 115 +++++++++++++++++++++++++++++++++++++++++
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5 files changed, 162 insertions(+)
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create mode 100644 lib/test_memcat_p.c
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diff --git a/include/linux/string.h b/include/linux/string.h
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index 1e0c442b941e..b8c2f80e858f 100644
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--- a/include/linux/string.h
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+++ b/include/linux/string.h
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@@ -135,6 +135,13 @@ static inline void *memset_p(void **p, void *v, __kernel_size_t n)
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return memset64((uint64_t *)p, (uintptr_t)v, n);
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}
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+extern void **__memcat_p(void **a, void **b);
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+#define memcat_p(a, b) ({ \
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+ BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)), \
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+ "type mismatch in memcat_p()"); \
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+ (typeof(*a) *)__memcat_p((void **)(a), (void **)(b)); \
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+})
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+
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#ifndef __HAVE_ARCH_MEMCPY
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extern void * memcpy(void *,const void *,__kernel_size_t);
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#endif
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diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
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index 46a910acce3f..cc6d3376cad4 100644
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--- a/lib/Kconfig.debug
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+++ b/lib/Kconfig.debug
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@@ -1966,6 +1966,14 @@ config TEST_DEBUG_VIRTUAL
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If unsure, say N.
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+config TEST_MEMCAT_P
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+ tristate "Test memcat_p() helper function"
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+ help
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+ Test the memcat_p() helper for correctly merging two
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+ pointer arrays together.
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+
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+ If unsure, say N.
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+
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endif # RUNTIME_TESTING_MENU
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config MEMTEST
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diff --git a/lib/Makefile b/lib/Makefile
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index 1d7a705d7207..d77eea2b94c4 100644
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--- a/lib/Makefile
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+++ b/lib/Makefile
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@@ -82,6 +82,7 @@ obj-$(CONFIG_TEST_UUID) += test_uuid.o
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obj-$(CONFIG_TEST_PARMAN) += test_parman.o
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obj-$(CONFIG_TEST_KMOD) += test_kmod.o
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obj-$(CONFIG_TEST_DEBUG_VIRTUAL) += test_debug_virtual.o
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+obj-$(CONFIG_TEST_MEMCAT_P) += test_memcat_p.o
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ifeq ($(CONFIG_DEBUG_KOBJECT),y)
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CFLAGS_kobject.o += -DDEBUG
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diff --git a/lib/string.c b/lib/string.c
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index f7f7770444bf..274b8593ecdf 100644
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--- a/lib/string.c
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+++ b/lib/string.c
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@@ -27,6 +27,7 @@
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#include <linux/export.h>
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#include <linux/bug.h>
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#include <linux/errno.h>
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+#include <linux/slab.h>
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#include <asm/byteorder.h>
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#include <asm/word-at-a-time.h>
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@@ -967,6 +968,36 @@ void *memscan(void *addr, int c, size_t size)
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EXPORT_SYMBOL(memscan);
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#endif
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+/*
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+ * Merge two NULL-terminated pointer arrays into a newly allocated
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+ * array, which is also NULL-terminated. Nomenclature is inspired by
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+ * memset_p() and memcat() found elsewhere in the kernel source tree.
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+ */
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+void **__memcat_p(void **a, void **b)
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+{
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+ void **p = a, **new;
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+ int nr;
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+
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+ /* count the elements in both arrays */
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+ for (nr = 0, p = a; *p; nr++, p++)
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+ ;
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+ for (p = b; *p; nr++, p++)
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+ ;
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+ /* one for the NULL-terminator */
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+ nr++;
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+
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+ new = kmalloc_array(nr, sizeof(void *), GFP_KERNEL);
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+ if (!new)
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+ return NULL;
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+
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+ /* nr -> last index; p points to NULL in b[] */
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+ for (nr--; nr >= 0; nr--, p = p == b ? &a[nr] : p - 1)
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+ new[nr] = *p;
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+
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+ return new;
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+}
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+EXPORT_SYMBOL_GPL(__memcat_p);
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+
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#ifndef __HAVE_ARCH_STRSTR
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/**
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* strstr - Find the first substring in a %NUL terminated string
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diff --git a/lib/test_memcat_p.c b/lib/test_memcat_p.c
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new file mode 100644
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index 000000000000..2b163a749ecb
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--- /dev/null
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+++ b/lib/test_memcat_p.c
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@@ -0,0 +1,115 @@
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+// SPDX-License-Identifier: GPL-2.0
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+/*
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+ * Test cases for memcat_p() in lib/string.c
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+ */
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+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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+
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+#include <linux/string.h>
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+#include <linux/slab.h>
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+#include <linux/module.h>
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+
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+struct test_struct {
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+ int num;
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+ unsigned int magic;
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+};
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+
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+#define MAGIC 0xf00ff00f
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+/* Size of each of the NULL-terminated input arrays */
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+#define INPUT_MAX 128
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+/* Expected number of non-NULL elements in the output array */
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+#define EXPECT (INPUT_MAX * 2 - 2)
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+
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+static int __init test_memcat_p_init(void)
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+{
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+ struct test_struct **in0, **in1, **out, **p;
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+ int err = -ENOMEM, i, r, total = 0;
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+
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+ in0 = kcalloc(INPUT_MAX, sizeof(*in0), GFP_KERNEL);
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+ if (!in0)
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+ return err;
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+
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+ in1 = kcalloc(INPUT_MAX, sizeof(*in1), GFP_KERNEL);
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+ if (!in1)
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+ goto err_free_in0;
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+
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+ for (i = 0, r = 1; i < INPUT_MAX - 1; i++) {
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+ in0[i] = kmalloc(sizeof(**in0), GFP_KERNEL);
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+ if (!in0[i])
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+ goto err_free_elements;
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+
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+ in1[i] = kmalloc(sizeof(**in1), GFP_KERNEL);
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+ if (!in1[i]) {
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+ kfree(in0[i]);
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+ goto err_free_elements;
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+ }
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+
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+ /* lifted from test_sort.c */
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+ r = (r * 725861) % 6599;
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+ in0[i]->num = r;
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+ in1[i]->num = -r;
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+ in0[i]->magic = MAGIC;
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+ in1[i]->magic = MAGIC;
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+ }
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+
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+ in0[i] = in1[i] = NULL;
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+
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+ out = memcat_p(in0, in1);
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+ if (!out)
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+ goto err_free_all_elements;
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+
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+ err = -EINVAL;
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+ for (i = 0, p = out; *p && (i < INPUT_MAX * 2 - 1); p++, i++) {
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+ total += (*p)->num;
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+
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+ if ((*p)->magic != MAGIC) {
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+ pr_err("test failed: wrong magic at %d: %u\n", i,
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+ (*p)->magic);
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+ goto err_free_out;
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+ }
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+ }
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+
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+ if (total) {
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+ pr_err("test failed: expected zero total, got %d\n", total);
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+ goto err_free_out;
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+ }
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+
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+ if (i != EXPECT) {
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+ pr_err("test failed: expected output size %d, got %d\n",
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+ EXPECT, i);
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+ goto err_free_out;
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+ }
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+
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+ for (i = 0; i < INPUT_MAX - 1; i++)
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+ if (out[i] != in0[i] || out[i + INPUT_MAX - 1] != in1[i]) {
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+ pr_err("test failed: wrong element order at %d\n", i);
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+ goto err_free_out;
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+ }
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+
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+ err = 0;
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+ pr_info("test passed\n");
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+
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+err_free_out:
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+ kfree(out);
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+err_free_all_elements:
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+ i = INPUT_MAX;
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+err_free_elements:
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+ for (i--; i >= 0; i--) {
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+ kfree(in1[i]);
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+ kfree(in0[i]);
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+ }
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+
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+ kfree(in1);
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+err_free_in0:
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+ kfree(in0);
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+
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+ return err;
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+}
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+
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+static void __exit test_memcat_p_exit(void)
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+{
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+}
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+
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+module_init(test_memcat_p_init);
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+module_exit(test_memcat_p_exit);
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+
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+MODULE_LICENSE("GPL");
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--
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https://clearlinux.org
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