From ce76d938dd98817f998c905e01fbb99b072c0bf6 Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Fri, 5 Oct 2018 15:43:05 +0300 Subject: lib: Add memcat_p(): paste 2 pointer arrays together This adds a helper to paste 2 pointer arrays together, useful for merging various types of attribute arrays. There are a few places in the kernel tree where this is open coded, and I just added one more in the STM class. The naming is inspired by memset_p() and memcat(), and partial credit for it goes to Andy Shevchenko. This patch adds the function wrapped in a type-enforcing macro and a test module. Signed-off-by: Alexander Shishkin Reviewed-by: Andy Shevchenko Tested-by: Mathieu Poirier Signed-off-by: Greg Kroah-Hartman --- lib/Kconfig.debug | 8 ++++ lib/Makefile | 1 + lib/string.c | 31 ++++++++++++++ lib/test_memcat_p.c | 115 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 155 insertions(+) create mode 100644 lib/test_memcat_p.c (limited to 'lib') diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 4966c4fbe7f7..c0176510262e 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1965,6 +1965,14 @@ config TEST_DEBUG_VIRTUAL If unsure, say N. +config TEST_MEMCAT_P + tristate "Test memcat_p() helper function" + help + Test the memcat_p() helper for correctly merging two + pointer arrays together. + + If unsure, say N. + endif # RUNTIME_TESTING_MENU config MEMTEST diff --git a/lib/Makefile b/lib/Makefile index ca3f7ebb900d..c2588a2d7b1e 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -71,6 +71,7 @@ obj-$(CONFIG_TEST_UUID) += test_uuid.o obj-$(CONFIG_TEST_PARMAN) += test_parman.o obj-$(CONFIG_TEST_KMOD) += test_kmod.o obj-$(CONFIG_TEST_DEBUG_VIRTUAL) += test_debug_virtual.o +obj-$(CONFIG_TEST_MEMCAT_P) += test_memcat_p.o ifeq ($(CONFIG_DEBUG_KOBJECT),y) CFLAGS_kobject.o += -DDEBUG diff --git a/lib/string.c b/lib/string.c index 2c0900a5d51a..453f35994eb6 100644 --- a/lib/string.c +++ b/lib/string.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include @@ -890,6 +891,36 @@ void *memscan(void *addr, int c, size_t size) EXPORT_SYMBOL(memscan); #endif +/* + * Merge two NULL-terminated pointer arrays into a newly allocated + * array, which is also NULL-terminated. Nomenclature is inspired by + * memset_p() and memcat() found elsewhere in the kernel source tree. + */ +void **__memcat_p(void **a, void **b) +{ + void **p = a, **new; + int nr; + + /* count the elements in both arrays */ + for (nr = 0, p = a; *p; nr++, p++) + ; + for (p = b; *p; nr++, p++) + ; + /* one for the NULL-terminator */ + nr++; + + new = kmalloc_array(nr, sizeof(void *), GFP_KERNEL); + if (!new) + return NULL; + + /* nr -> last index; p points to NULL in b[] */ + for (nr--; nr >= 0; nr--, p = p == b ? &a[nr] : p - 1) + new[nr] = *p; + + return new; +} +EXPORT_SYMBOL_GPL(__memcat_p); + #ifndef __HAVE_ARCH_STRSTR /** * strstr - Find the first substring in a %NUL terminated string diff --git a/lib/test_memcat_p.c b/lib/test_memcat_p.c new file mode 100644 index 000000000000..2b163a749ecb --- /dev/null +++ b/lib/test_memcat_p.c @@ -0,0 +1,115 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Test cases for memcat_p() in lib/string.c + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include + +struct test_struct { + int num; + unsigned int magic; +}; + +#define MAGIC 0xf00ff00f +/* Size of each of the NULL-terminated input arrays */ +#define INPUT_MAX 128 +/* Expected number of non-NULL elements in the output array */ +#define EXPECT (INPUT_MAX * 2 - 2) + +static int __init test_memcat_p_init(void) +{ + struct test_struct **in0, **in1, **out, **p; + int err = -ENOMEM, i, r, total = 0; + + in0 = kcalloc(INPUT_MAX, sizeof(*in0), GFP_KERNEL); + if (!in0) + return err; + + in1 = kcalloc(INPUT_MAX, sizeof(*in1), GFP_KERNEL); + if (!in1) + goto err_free_in0; + + for (i = 0, r = 1; i < INPUT_MAX - 1; i++) { + in0[i] = kmalloc(sizeof(**in0), GFP_KERNEL); + if (!in0[i]) + goto err_free_elements; + + in1[i] = kmalloc(sizeof(**in1), GFP_KERNEL); + if (!in1[i]) { + kfree(in0[i]); + goto err_free_elements; + } + + /* lifted from test_sort.c */ + r = (r * 725861) % 6599; + in0[i]->num = r; + in1[i]->num = -r; + in0[i]->magic = MAGIC; + in1[i]->magic = MAGIC; + } + + in0[i] = in1[i] = NULL; + + out = memcat_p(in0, in1); + if (!out) + goto err_free_all_elements; + + err = -EINVAL; + for (i = 0, p = out; *p && (i < INPUT_MAX * 2 - 1); p++, i++) { + total += (*p)->num; + + if ((*p)->magic != MAGIC) { + pr_err("test failed: wrong magic at %d: %u\n", i, + (*p)->magic); + goto err_free_out; + } + } + + if (total) { + pr_err("test failed: expected zero total, got %d\n", total); + goto err_free_out; + } + + if (i != EXPECT) { + pr_err("test failed: expected output size %d, got %d\n", + EXPECT, i); + goto err_free_out; + } + + for (i = 0; i < INPUT_MAX - 1; i++) + if (out[i] != in0[i] || out[i + INPUT_MAX - 1] != in1[i]) { + pr_err("test failed: wrong element order at %d\n", i); + goto err_free_out; + } + + err = 0; + pr_info("test passed\n"); + +err_free_out: + kfree(out); +err_free_all_elements: + i = INPUT_MAX; +err_free_elements: + for (i--; i >= 0; i--) { + kfree(in1[i]); + kfree(in0[i]); + } + + kfree(in1); +err_free_in0: + kfree(in0); + + return err; +} + +static void __exit test_memcat_p_exit(void) +{ +} + +module_init(test_memcat_p_init); +module_exit(test_memcat_p_exit); + +MODULE_LICENSE("GPL"); -- cgit From 93048c0944150b316a15f92c41a4d626c8df37fd Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Tue, 16 Oct 2018 14:13:40 +0300 Subject: lib: Fix ia64 bootloader linkage kbuild robot reports that since commit ce76d938dd98 ("lib: Add memcat_p(): paste 2 pointer arrays together") the ia64/hp/sim/boot fails to link: > LD arch/ia64/hp/sim/boot/bootloader > lib/string.o: In function `__memcat_p': > string.c:(.text+0x1f22): undefined reference to `__kmalloc' > string.c:(.text+0x1ff2): undefined reference to `__kmalloc' > make[1]: *** [arch/ia64/hp/sim/boot/Makefile:37: arch/ia64/hp/sim/boot/bootloader] Error 1 The reason is, the above commit, via __memcat_p(), adds a call to __kmalloc to string.o, which happens to be used in the bootloader, but there's no kmalloc or slab or anything. Since the linker would only pull in objects that contain referenced symbols, moving __memcat_p() to a different compilation unit solves the problem. Fixes: ce76d938dd98 ("lib: Add memcat_p(): paste 2 pointer arrays together") Signed-off-by: Alexander Shishkin Reported-by: kbuild test robot Cc: Fenghua Yu Cc: Tony Luck Cc: Joe Perches Signed-off-by: Greg Kroah-Hartman --- lib/Makefile | 2 +- lib/memcat_p.c | 34 ++++++++++++++++++++++++++++++++++ lib/string.c | 30 ------------------------------ lib/test_memcat_p.c | 2 +- 4 files changed, 36 insertions(+), 32 deletions(-) create mode 100644 lib/memcat_p.c (limited to 'lib') diff --git a/lib/Makefile b/lib/Makefile index c2588a2d7b1e..40e79f88c3cd 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -24,7 +24,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ flex_proportions.o ratelimit.o show_mem.o \ is_single_threaded.o plist.o decompress.o kobject_uevent.o \ earlycpio.o seq_buf.o siphash.o dec_and_lock.o \ - nmi_backtrace.o nodemask.o win_minmax.o + nmi_backtrace.o nodemask.o win_minmax.o memcat_p.o lib-$(CONFIG_PRINTK) += dump_stack.o lib-$(CONFIG_MMU) += ioremap.o diff --git a/lib/memcat_p.c b/lib/memcat_p.c new file mode 100644 index 000000000000..b810fbc66962 --- /dev/null +++ b/lib/memcat_p.c @@ -0,0 +1,34 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +/* + * Merge two NULL-terminated pointer arrays into a newly allocated + * array, which is also NULL-terminated. Nomenclature is inspired by + * memset_p() and memcat() found elsewhere in the kernel source tree. + */ +void **__memcat_p(void **a, void **b) +{ + void **p = a, **new; + int nr; + + /* count the elements in both arrays */ + for (nr = 0, p = a; *p; nr++, p++) + ; + for (p = b; *p; nr++, p++) + ; + /* one for the NULL-terminator */ + nr++; + + new = kmalloc_array(nr, sizeof(void *), GFP_KERNEL); + if (!new) + return NULL; + + /* nr -> last index; p points to NULL in b[] */ + for (nr--; nr >= 0; nr--, p = p == b ? &a[nr] : p - 1) + new[nr] = *p; + + return new; +} +EXPORT_SYMBOL_GPL(__memcat_p); + diff --git a/lib/string.c b/lib/string.c index 453f35994eb6..38e4ca08e757 100644 --- a/lib/string.c +++ b/lib/string.c @@ -891,36 +891,6 @@ void *memscan(void *addr, int c, size_t size) EXPORT_SYMBOL(memscan); #endif -/* - * Merge two NULL-terminated pointer arrays into a newly allocated - * array, which is also NULL-terminated. Nomenclature is inspired by - * memset_p() and memcat() found elsewhere in the kernel source tree. - */ -void **__memcat_p(void **a, void **b) -{ - void **p = a, **new; - int nr; - - /* count the elements in both arrays */ - for (nr = 0, p = a; *p; nr++, p++) - ; - for (p = b; *p; nr++, p++) - ; - /* one for the NULL-terminator */ - nr++; - - new = kmalloc_array(nr, sizeof(void *), GFP_KERNEL); - if (!new) - return NULL; - - /* nr -> last index; p points to NULL in b[] */ - for (nr--; nr >= 0; nr--, p = p == b ? &a[nr] : p - 1) - new[nr] = *p; - - return new; -} -EXPORT_SYMBOL_GPL(__memcat_p); - #ifndef __HAVE_ARCH_STRSTR /** * strstr - Find the first substring in a %NUL terminated string diff --git a/lib/test_memcat_p.c b/lib/test_memcat_p.c index 2b163a749ecb..849c477d49d0 100644 --- a/lib/test_memcat_p.c +++ b/lib/test_memcat_p.c @@ -1,6 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 /* - * Test cases for memcat_p() in lib/string.c + * Test cases for memcat_p() in lib/memcat_p.c */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt -- cgit