From ccf7a6d457a8bd618c77468c38842b3f9d82cef4 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Tue, 21 Aug 2018 21:56:59 -0700 Subject: lib/bitmap.c: drop unnecessary 0 check for u32 array operations nbits == 0 is safe to be supplied to the function body, so remove unnecessary checks in bitmap_to_arr32() and bitmap_from_arr32(). Link: http://lkml.kernel.org/r/20180531131914.44352-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Acked-by: Yury Norov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/bitmap.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) (limited to 'lib') diff --git a/lib/bitmap.c b/lib/bitmap.c index 730969c681cb..2fd07f6df0b8 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -1152,14 +1152,10 @@ EXPORT_SYMBOL(bitmap_free); * @buf: array of u32 (in host byte order), the source bitmap * @nbits: number of bits in @bitmap */ -void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, - unsigned int nbits) +void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned int nbits) { unsigned int i, halfwords; - if (!nbits) - return; - halfwords = DIV_ROUND_UP(nbits, 32); for (i = 0; i < halfwords; i++) { bitmap[i/2] = (unsigned long) buf[i]; @@ -1183,9 +1179,6 @@ void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits) { unsigned int i, halfwords; - if (!nbits) - return; - halfwords = DIV_ROUND_UP(nbits, 32); for (i = 0; i < halfwords; i++) { buf[i] = (u32) (bitmap[i/2] & UINT_MAX); -- cgit v1.2.3 From b15f5f1ae18a70f2db0ec4b4e5fa525420a67270 Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Tue, 21 Aug 2018 21:57:07 -0700 Subject: lib/test_debug_virtual.c: make struct pointer foo static The pointer foo is local to the source and does not need to be in global scope, so make it static. Cleans up sparse warning: symbol 'foo' was not declared. Should it be static? Link: http://lkml.kernel.org/r/20180624112206.5722-1-colin.king@canonical.com Signed-off-by: Colin Ian King Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/test_debug_virtual.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib') diff --git a/lib/test_debug_virtual.c b/lib/test_debug_virtual.c index b9cdeecc19dc..d5a06addeb27 100644 --- a/lib/test_debug_virtual.c +++ b/lib/test_debug_virtual.c @@ -15,7 +15,7 @@ struct foo { unsigned int bar; }; -struct foo *foo; +static struct foo *foo; static int __init test_debug_virtual_init(void) { -- cgit v1.2.3 From feba04fd2cf8f6a74865338df2e3e1e94d6cfd13 Mon Sep 17 00:00:00 2001 From: Coly Li Date: Tue, 21 Aug 2018 21:57:11 -0700 Subject: lib: add crc64 calculation routines Patch series "add crc64 calculation as kernel library", v5. This patchset adds basic implementation of crc64 calculation as a Linux kernel library. Since bcache already does crc64 by itself, this patchset also modifies bcache code to use the new crc64 library routine. Currently bcache is the only user of crc64 calculation, another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to make crc64 calculation to be a public library. bcache uses crc64 as storage checksum, if a change of crc lib routines results an inconsistent result, the unmatched checksum may make bcache 'think' the on-disk is corrupted, such a change should be avoided or detected as early as possible. Therefore a patch is being prepared which adds a crc test framework, to check consistency of different calculations. This patch (of 2): Add the re-write crc64 calculation routines for Linux kernel. The CRC64 polynomical arithmetic follows ECMA-182 specification, inspired by CRC paper of Dr. Ross N. Williams (see http://www.ross.net/crc/download/crc_v3.txt) and other public domain implementations. All the changes work in this way, - When Linux kernel is built, host program lib/gen_crc64table.c will be compiled to lib/gen_crc64table and executed. - The output of gen_crc64table execution is an array called as lookup table (a.k.a POLY 0x42f0e1eba9ea369) which contain 256 64-bit long numbers, this table is dumped into header file lib/crc64table.h. - Then the header file is included by lib/crc64.c for normal 64bit crc calculation. - Function declaration of the crc64 calculation routines is placed in include/linux/crc64.h Currently bcache is the only user of crc64_be(), another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to move crc64 calculation into lib/crc64.c as public code. [colyli@suse.de: fix review comments from v4] Link: http://lkml.kernel.org/r/20180726053352.2781-2-colyli@suse.de Link: http://lkml.kernel.org/r/20180718165545.1622-2-colyli@suse.de Signed-off-by: Coly Li Co-developed-by: Andy Shevchenko Signed-off-by: Andy Shevchenko Reviewed-by: Hannes Reinecke Cc: Greg Kroah-Hartman Cc: Andy Shevchenko Cc: Michael Lyle Cc: Kent Overstreet Cc: Thomas Gleixner Cc: Kate Stewart Cc: Eric Biggers Cc: Randy Dunlap Cc: Noah Massey Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/crc64.h | 11 +++++++++ lib/.gitignore | 2 ++ lib/Kconfig | 8 ++++++ lib/Makefile | 11 +++++++++ lib/crc64.c | 56 ++++++++++++++++++++++++++++++++++++++++++ lib/gen_crc64table.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 156 insertions(+) create mode 100644 include/linux/crc64.h create mode 100644 lib/crc64.c create mode 100644 lib/gen_crc64table.c (limited to 'lib') diff --git a/include/linux/crc64.h b/include/linux/crc64.h new file mode 100644 index 000000000000..c756e65a1b58 --- /dev/null +++ b/include/linux/crc64.h @@ -0,0 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * See lib/crc64.c for the related specification and polynomial arithmetic. + */ +#ifndef _LINUX_CRC64_H +#define _LINUX_CRC64_H + +#include + +u64 __pure crc64_be(u64 crc, const void *p, size_t len); +#endif /* _LINUX_CRC64_H */ diff --git a/lib/.gitignore b/lib/.gitignore index 09aae85418ab..f2a39c9e5485 100644 --- a/lib/.gitignore +++ b/lib/.gitignore @@ -2,5 +2,7 @@ # Generated files # gen_crc32table +gen_crc64table crc32table.h +crc64table.h oid_registry_data.c diff --git a/lib/Kconfig b/lib/Kconfig index 706836ec314d..9c10b9852563 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -170,6 +170,14 @@ config CRC32_BIT endchoice +config CRC64 + tristate "CRC64 functions" + help + This option is provided for the case where no in-kernel-tree + modules require CRC64 functions, but a module built outside + the kernel tree does. Such modules that use library CRC64 + functions require M here. + config CRC4 tristate "CRC4 functions" help diff --git a/lib/Makefile b/lib/Makefile index d95bb2525101..9baefb6cb1a1 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -103,6 +103,7 @@ obj-$(CONFIG_CRC16) += crc16.o obj-$(CONFIG_CRC_T10DIF)+= crc-t10dif.o obj-$(CONFIG_CRC_ITU_T) += crc-itu-t.o obj-$(CONFIG_CRC32) += crc32.o +obj-$(CONFIG_CRC64) += crc64.o obj-$(CONFIG_CRC32_SELFTEST) += crc32test.o obj-$(CONFIG_CRC4) += crc4.o obj-$(CONFIG_CRC7) += crc7.o @@ -217,7 +218,9 @@ obj-$(CONFIG_FONT_SUPPORT) += fonts/ obj-$(CONFIG_PRIME_NUMBERS) += prime_numbers.o hostprogs-y := gen_crc32table +hostprogs-y += gen_crc64table clean-files := crc32table.h +clean-files += crc64table.h $(obj)/crc32.o: $(obj)/crc32table.h @@ -227,6 +230,14 @@ quiet_cmd_crc32 = GEN $@ $(obj)/crc32table.h: $(obj)/gen_crc32table $(call cmd,crc32) +$(obj)/crc64.o: $(obj)/crc64table.h + +quiet_cmd_crc64 = GEN $@ + cmd_crc64 = $< > $@ + +$(obj)/crc64table.h: $(obj)/gen_crc64table + $(call cmd,crc64) + # # Build a fast OID lookip registry from include/linux/oid_registry.h # diff --git a/lib/crc64.c b/lib/crc64.c new file mode 100644 index 000000000000..0ef8ae6ac047 --- /dev/null +++ b/lib/crc64.c @@ -0,0 +1,56 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Normal 64-bit CRC calculation. + * + * This is a basic crc64 implementation following ECMA-182 specification, + * which can be found from, + * http://www.ecma-international.org/publications/standards/Ecma-182.htm + * + * Dr. Ross N. Williams has a great document to introduce the idea of CRC + * algorithm, here the CRC64 code is also inspired by the table-driven + * algorithm and detail example from this paper. This paper can be found + * from, + * http://www.ross.net/crc/download/crc_v3.txt + * + * crc64table[256] is the lookup table of a table-driven 64-bit CRC + * calculation, which is generated by gen_crc64table.c in kernel build + * time. The polynomial of crc64 arithmetic is from ECMA-182 specification + * as well, which is defined as, + * + * x^64 + x^62 + x^57 + x^55 + x^54 + x^53 + x^52 + x^47 + x^46 + x^45 + + * x^40 + x^39 + x^38 + x^37 + x^35 + x^33 + x^32 + x^31 + x^29 + x^27 + + * x^24 + x^23 + x^22 + x^21 + x^19 + x^17 + x^13 + x^12 + x^10 + x^9 + + * x^7 + x^4 + x + 1 + * + * Copyright 2018 SUSE Linux. + * Author: Coly Li + */ + +#include +#include +#include "crc64table.h" + +MODULE_DESCRIPTION("CRC64 calculations"); +MODULE_LICENSE("GPL v2"); + +/** + * crc64_be - Calculate bitwise big-endian ECMA-182 CRC64 + * @crc: seed value for computation. 0 or (u64)~0 for a new CRC calculation, + or the previous crc64 value if computing incrementally. + * @p: pointer to buffer over which CRC64 is run + * @len: length of buffer @p + */ +u64 __pure crc64_be(u64 crc, const void *p, size_t len) +{ + size_t i, t; + + const unsigned char *_p = p; + + for (i = 0; i < len; i++) { + t = ((crc >> 56) ^ (*_p++)) & 0xFF; + crc = crc64table[t] ^ (crc << 8); + } + + return crc; +} +EXPORT_SYMBOL_GPL(crc64_be); diff --git a/lib/gen_crc64table.c b/lib/gen_crc64table.c new file mode 100644 index 000000000000..9011926e4162 --- /dev/null +++ b/lib/gen_crc64table.c @@ -0,0 +1,68 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Generate lookup table for the table-driven CRC64 calculation. + * + * gen_crc64table is executed in kernel build time and generates + * lib/crc64table.h. This header is included by lib/crc64.c for + * the table-driven CRC64 calculation. + * + * See lib/crc64.c for more information about which specification + * and polynomial arithmetic that gen_crc64table.c follows to + * generate the lookup table. + * + * Copyright 2018 SUSE Linux. + * Author: Coly Li + */ +#include +#include + +#include + +#define CRC64_ECMA182_POLY 0x42F0E1EBA9EA3693ULL + +static uint64_t crc64_table[256] = {0}; + +static void generate_crc64_table(void) +{ + uint64_t i, j, c, crc; + + for (i = 0; i < 256; i++) { + crc = 0; + c = i << 56; + + for (j = 0; j < 8; j++) { + if ((crc ^ c) & 0x8000000000000000ULL) + crc = (crc << 1) ^ CRC64_ECMA182_POLY; + else + crc <<= 1; + c <<= 1; + } + + crc64_table[i] = crc; + } +} + +static void print_crc64_table(void) +{ + int i; + + printf("/* this file is generated - do not edit */\n\n"); + printf("#include \n"); + printf("#include \n\n"); + printf("static const u64 ____cacheline_aligned crc64table[256] = {\n"); + for (i = 0; i < 256; i++) { + printf("\t0x%016" PRIx64 "ULL", crc64_table[i]); + if (i & 0x1) + printf(",\n"); + else + printf(", "); + } + printf("};\n"); +} + +int main(int argc, char *argv[]) +{ + generate_crc64_table(); + print_crc64_table(); + return 0; +} -- cgit v1.2.3 From fd7338ef624fab2efbeb011c3e790693b4199c8e Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Tue, 21 Aug 2018 21:57:18 -0700 Subject: lib/Kconfig: remove 'default n' for tests It seems contributors follow the style of Kconfig entries where explicit 'default n' is present. The default 'default' is 'n' already, thus, drop these lines from Kconfig to make it more clear. Link: http://lkml.kernel.org/r/20180719085131.79541-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Acked-by: Coly Li Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/Kconfig | 1 - lib/Kconfig.debug | 17 ----------------- 2 files changed, 18 deletions(-) (limited to 'lib') diff --git a/lib/Kconfig b/lib/Kconfig index 9c10b9852563..a3928d4438b5 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -231,7 +231,6 @@ config AUDIT_COMPAT_GENERIC config RANDOM32_SELFTEST bool "PRNG perform self test on init" - default n help This option enables the 32 bit PRNG library functions to perform a self test on initialization. diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index ab1b599202bc..3589765141a8 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1220,7 +1220,6 @@ config LOCK_TORTURE_TEST tristate "torture tests for locking" depends on DEBUG_KERNEL select TORTURE_TEST - default n help This option provides a kernel module that runs torture tests on kernel locking primitives. The kernel module may be built @@ -1687,7 +1686,6 @@ config LKDTM tristate "Linux Kernel Dump Test Tool Module" depends on DEBUG_FS depends on BLOCK - default n help This module enables testing of the different dumping mechanisms by inducing system failures at predefined crash points. @@ -1721,7 +1719,6 @@ config KPROBES_SANITY_TEST bool "Kprobes sanity tests" depends on DEBUG_KERNEL depends on KPROBES - default n help This option provides for testing basic kprobes functionality on boot. Samples of kprobe and kretprobe are inserted and @@ -1732,7 +1729,6 @@ config KPROBES_SANITY_TEST config BACKTRACE_SELF_TEST tristate "Self test for the backtrace code" depends on DEBUG_KERNEL - default n help This option provides a kernel module that can be used to test the kernel stack backtrace code. This option is not useful @@ -1802,7 +1798,6 @@ config TEST_PRINTF config TEST_BITMAP tristate "Test bitmap_*() family of functions at runtime" - default n help Enable this option to test the bitmap functions at boot. @@ -1823,7 +1818,6 @@ config TEST_OVERFLOW config TEST_RHASHTABLE tristate "Perform selftest on resizable hash table" - default n help Enable this option to test the rhashtable functions at boot. @@ -1831,7 +1825,6 @@ config TEST_RHASHTABLE config TEST_HASH tristate "Perform selftest on hash functions" - default n help Enable this option to test the kernel's integer (), string (), and siphash () @@ -1842,7 +1835,6 @@ config TEST_HASH config TEST_PARMAN tristate "Perform selftest on priority array manager" - default n depends on PARMAN help Enable this option to test priority array manager on boot @@ -1852,7 +1844,6 @@ config TEST_PARMAN config TEST_LKM tristate "Test module loading with 'hello world' module" - default n depends on m help This builds the "test_module" module that emits "Hello, world" @@ -1866,7 +1857,6 @@ config TEST_LKM config TEST_USER_COPY tristate "Test user/kernel boundary protections" - default n depends on m help This builds the "test_user_copy" module that runs sanity checks @@ -1879,7 +1869,6 @@ config TEST_USER_COPY config TEST_BPF tristate "Test BPF filter functionality" - default n depends on m && NET help This builds the "test_bpf" module that runs various test vectors @@ -1893,7 +1882,6 @@ config TEST_BPF config FIND_BIT_BENCHMARK tristate "Test find_bit functions" - default n help This builds the "test_find_bit" module that measure find_*_bit() functions performance. @@ -1902,7 +1890,6 @@ config FIND_BIT_BENCHMARK config TEST_FIRMWARE tristate "Test firmware loading via userspace interface" - default n depends on FW_LOADER help This builds the "test_firmware" module that creates a userspace @@ -1915,7 +1902,6 @@ config TEST_FIRMWARE config TEST_SYSCTL tristate "sysctl test driver" - default n depends on PROC_SYSCTL help This builds the "test_sysctl" module. This driver enables to test the @@ -1926,7 +1912,6 @@ config TEST_SYSCTL config TEST_UDELAY tristate "udelay test driver" - default n help This builds the "udelay_test" module that helps to make sure that udelay() is working properly. @@ -1935,7 +1920,6 @@ config TEST_UDELAY config TEST_STATIC_KEYS tristate "Test static keys" - default n depends on m help Test the static key interfaces. @@ -1944,7 +1928,6 @@ config TEST_STATIC_KEYS config TEST_KMOD tristate "kmod stress tester" - default n depends on m depends on BLOCK && (64BIT || LBDAF) # for XFS, BTRFS depends on NETDEVICES && NET_CORE && INET # for TUN -- cgit v1.2.3 From de9df3993cfffde468c1c226382f24cec7e9fedc Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Tue, 21 Aug 2018 21:57:22 -0700 Subject: lib/test_hexdump.c: fix failure on big endian cpu On a big endian cpu, test_hexdump fails as follows. The logs show that bytes are expected in reversed order. [...] test_hexdump: Len: 24 buflen: 130 strlen: 97 test_hexdump: Result: 97 'be32db7b 0a1893b2 70bac424 7d83349b a69c31ad 9c0face9 .2.{....p..$}.4...1.....' test_hexdump: Expect: 97 '7bdb32be b293180a 24c4ba70 9b34837d ad319ca6 e9ac0f9c .2.{....p..$}.4...1.....' test_hexdump: Len: 8 buflen: 130 strlen: 77 test_hexdump: Result: 77 'be32db7b0a1893b2 .2.{....' test_hexdump: Expect: 77 'b293180a7bdb32be .2.{....' test_hexdump: Len: 6 buflen: 131 strlen: 87 test_hexdump: Result: 87 'be32 db7b 0a18 .2.{..' test_hexdump: Expect: 87 '32be 7bdb 180a .2.{..' test_hexdump: Len: 24 buflen: 131 strlen: 97 test_hexdump: Result: 97 'be32db7b 0a1893b2 70bac424 7d83349b a69c31ad 9c0face9 .2.{....p..$}.4...1.....' test_hexdump: Expect: 97 '7bdb32be b293180a 24c4ba70 9b34837d ad319ca6 e9ac0f9c .2.{....p..$}.4...1.....' test_hexdump: Len: 32 buflen: 131 strlen: 101 test_hexdump: Result: 101 'be32db7b0a1893b2 70bac4247d83349b a69c31ad9c0face9 4cd1199943b1af0c .2.{....p..$}.4...1.....L...C...' test_hexdump: Expect: 101 'b293180a7bdb32be 9b34837d24c4ba70 e9ac0f9cad319ca6 0cafb1439919d14c .2.{....p..$}.4...1.....L...C...' test_hexdump: failed 801 out of 1184 tests This patch fixes it. Link: http://lkml.kernel.org/r/f3112437f62c2f48300535510918e8be1dceacfb.1533610877.git.christophe.leroy@c-s.fr Fixes: 64d1d77a44697 ("hexdump: introduce test suite") Signed-off-by: Christophe Leroy Reviewed-by: Andy Shevchenko Cc: Michael Ellerman Cc: rashmica Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/test_hexdump.c | 28 +++++++++++++++++++++++----- 1 file changed, 23 insertions(+), 5 deletions(-) (limited to 'lib') diff --git a/lib/test_hexdump.c b/lib/test_hexdump.c index 3f415d8101f3..626f580b4ff7 100644 --- a/lib/test_hexdump.c +++ b/lib/test_hexdump.c @@ -18,7 +18,7 @@ static const unsigned char data_b[] = { static const unsigned char data_a[] = ".2.{....p..$}.4...1.....L...C..."; -static const char * const test_data_1_le[] __initconst = { +static const char * const test_data_1[] __initconst = { "be", "32", "db", "7b", "0a", "18", "93", "b2", "70", "ba", "c4", "24", "7d", "83", "34", "9b", "a6", "9c", "31", "ad", "9c", "0f", "ac", "e9", @@ -32,16 +32,33 @@ static const char * const test_data_2_le[] __initconst = { "d14c", "9919", "b143", "0caf", }; +static const char * const test_data_2_be[] __initconst = { + "be32", "db7b", "0a18", "93b2", + "70ba", "c424", "7d83", "349b", + "a69c", "31ad", "9c0f", "ace9", + "4cd1", "1999", "43b1", "af0c", +}; + static const char * const test_data_4_le[] __initconst = { "7bdb32be", "b293180a", "24c4ba70", "9b34837d", "ad319ca6", "e9ac0f9c", "9919d14c", "0cafb143", }; +static const char * const test_data_4_be[] __initconst = { + "be32db7b", "0a1893b2", "70bac424", "7d83349b", + "a69c31ad", "9c0face9", "4cd11999", "43b1af0c", +}; + static const char * const test_data_8_le[] __initconst = { "b293180a7bdb32be", "9b34837d24c4ba70", "e9ac0f9cad319ca6", "0cafb1439919d14c", }; +static const char * const test_data_8_be[] __initconst = { + "be32db7b0a1893b2", "70bac4247d83349b", + "a69c31ad9c0face9", "4cd1199943b1af0c", +}; + #define FILL_CHAR '#' static unsigned total_tests __initdata; @@ -56,6 +73,7 @@ static void __init test_hexdump_prepare_test(size_t len, int rowsize, size_t l = len; int gs = groupsize, rs = rowsize; unsigned int i; + const bool is_be = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN); if (rs != 16 && rs != 32) rs = 16; @@ -67,13 +85,13 @@ static void __init test_hexdump_prepare_test(size_t len, int rowsize, gs = 1; if (gs == 8) - result = test_data_8_le; + result = is_be ? test_data_8_be : test_data_8_le; else if (gs == 4) - result = test_data_4_le; + result = is_be ? test_data_4_be : test_data_4_le; else if (gs == 2) - result = test_data_2_le; + result = is_be ? test_data_2_be : test_data_2_le; else - result = test_data_1_le; + result = test_data_1; /* hex dump */ p = test; -- cgit v1.2.3 From 93f976b5190df32793908d49165f78e67fcb66cf Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Tue, 21 Aug 2018 22:01:45 -0700 Subject: lib/rhashtable: simplify bucket_table_alloc() As of ce91f6ee5b3b ("mm: kvmalloc does not fallback to vmalloc for incompatible gfp flags") we can simplify the caller and trust kvzalloc() to just do the right thing. For the case of the GFP_ATOMIC context, we can drop the __GFP_NORETRY flag for obvious reasons, and for the __GFP_NOWARN case, however, it is changed such that the caller passes the flag instead of making bucket_table_alloc() handle it. This slightly changes the gfp flags passed on to nested_table_alloc() as it will now also use GFP_ATOMIC | __GFP_NOWARN. However, I consider this a positive consequence as for the same reasons we want nowarn semantics in bucket_table_alloc(). [manfred@colorfullife.com: commit id extended to 12 digits, line wraps updated] Link: http://lkml.kernel.org/r/20180712185241.4017-8-manfred@colorfullife.com Signed-off-by: Davidlohr Bueso Signed-off-by: Manfred Spraul Acked-by: Michal Hocko Cc: Dmitry Vyukov Cc: Herbert Xu Cc: Kees Cook Cc: Michael Kerrisk Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/rhashtable.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) (limited to 'lib') diff --git a/lib/rhashtable.c b/lib/rhashtable.c index ae4223e0f5bc..238c8daa9852 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -174,10 +174,7 @@ static struct bucket_table *bucket_table_alloc(struct rhashtable *ht, int i; size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]); - if (gfp != GFP_KERNEL) - tbl = kzalloc(size, gfp | __GFP_NOWARN | __GFP_NORETRY); - else - tbl = kvzalloc(size, gfp); + tbl = kvzalloc(size, gfp); size = nbuckets; @@ -450,7 +447,7 @@ static int rhashtable_insert_rehash(struct rhashtable *ht, err = -ENOMEM; - new_tbl = bucket_table_alloc(ht, size, GFP_ATOMIC); + new_tbl = bucket_table_alloc(ht, size, GFP_ATOMIC | __GFP_NOWARN); if (new_tbl == NULL) goto fail; -- cgit v1.2.3 From 2d22ecf6db1c390974476758681ba4229018e774 Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Tue, 21 Aug 2018 22:01:48 -0700 Subject: lib/rhashtable: guarantee initial hashtable allocation rhashtable_init() may fail due to -ENOMEM, thus making the entire api unusable. This patch removes this scenario, however unlikely. In order to guarantee memory allocation, this patch always ends up doing GFP_KERNEL|__GFP_NOFAIL for both the tbl as well as alloc_bucket_spinlocks(). Upon the first table allocation failure, we shrink the size to the smallest value that makes sense and retry with __GFP_NOFAIL semantics. With the defaults, this means that from 64 buckets, we retry with only 4. Any later issues regarding performance due to collisions or larger table resizing (when more memory becomes available) is the least of our problems. Link: http://lkml.kernel.org/r/20180712185241.4017-9-manfred@colorfullife.com Signed-off-by: Davidlohr Bueso Signed-off-by: Manfred Spraul Acked-by: Herbert Xu Cc: Dmitry Vyukov Cc: Kees Cook Cc: Michael Kerrisk Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/rhashtable.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) (limited to 'lib') diff --git a/lib/rhashtable.c b/lib/rhashtable.c index 238c8daa9852..310e29b51507 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -178,10 +178,11 @@ static struct bucket_table *bucket_table_alloc(struct rhashtable *ht, size = nbuckets; - if (tbl == NULL && gfp != GFP_KERNEL) { + if (tbl == NULL && (gfp & ~__GFP_NOFAIL) != GFP_KERNEL) { tbl = nested_bucket_table_alloc(ht, nbuckets, gfp); nbuckets = 0; } + if (tbl == NULL) return NULL; @@ -1057,9 +1058,16 @@ int rhashtable_init(struct rhashtable *ht, } } + /* + * This is api initialization and thus we need to guarantee the + * initial rhashtable allocation. Upon failure, retry with the + * smallest possible size with __GFP_NOFAIL semantics. + */ tbl = bucket_table_alloc(ht, size, GFP_KERNEL); - if (tbl == NULL) - return -ENOMEM; + if (unlikely(tbl == NULL)) { + size = max_t(u16, ht->p.min_size, HASH_MIN_SIZE); + tbl = bucket_table_alloc(ht, size, GFP_KERNEL | __GFP_NOFAIL); + } atomic_set(&ht->nelems, 0); -- cgit v1.2.3