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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Jason Gunthorpe , John Hubbard , Peter Xu , Leon Romanovsky , Jonathan Corbet , Shuah Khan , Mark Brown , Anshuman Khandual , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Sarthak Sharma Subject: [PATCH v7 2/6] tools/lib/mm: add shared file helpers Date: Thu, 13 Aug 2026 23:42:26 +0530 Message-ID: <20260813181230.483746-3-sarthak.sharma@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260813181230.483746-1-sarthak.sharma@arm.com> References: <20260813181230.483746-1-sarthak.sharma@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Queue-Id: CD1C220002 X-Rspamd-Server: rspam07 X-Stat-Signature: n4ckkwkdg9jxi3zzxh345g7913es7kkm X-HE-Tag: 1786644814-398050 X-HE-Meta: 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 cn1JhgGj VLzvfX13zAli9n90Eb8iK3QNVw5EKDLyAOs796m4s0Zhac+b6c3gv37hUiqmTzezNDUNrVvj/FKKb1noH4E5kQ0bleBAqM9e9lvgdKIKA+LJUIXNFsHVBP1VKq9PtQmgvTZ6JaXlDUNvgmiuOW/ZswkQ86SshBLgOC5NOhKPPyJ7dtfY5PmiUF0udc4aZQF2a3uYzpNITDS6AUl1KznBuULhXjC5UzeVmmSSWGk5gogWN6pqsM2EIUyj7MQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Move read_file(), write_file(), read_num(), write_num() and write_num_ignore_einval() out of tools/testing/selftests/mm/vm_util.c into a new shared helper under tools/lib/mm/. These helpers are used by mm selftests today and will also be needed by shared hugepage helpers in subsequent patches. Move them to a generic location so they can be reused outside selftests as well. Keep the helpers exposed to mm selftests through vm_util.h by including the new shared header there, and link the new helper into the selftests/mm build. Update the explicit x86 protection_keys 32-bit and 64-bit build rules to preserve prerequisite paths, now that file_utils.c is built from tools/lib/mm. Add tools/lib/mm/ to the MEMORY MANAGEMENT - MISC entry in MAINTAINERS. Signed-off-by: Sarthak Sharma --- MAINTAINERS | 1 + tools/lib/mm/file_utils.c | 104 +++++++++++++++++++++++++++ tools/lib/mm/file_utils.h | 13 ++++ tools/testing/selftests/mm/Makefile | 11 +-- tools/testing/selftests/mm/vm_util.c | 95 ------------------------ tools/testing/selftests/mm/vm_util.h | 7 +- 6 files changed, 125 insertions(+), 106 deletions(-) create mode 100644 tools/lib/mm/file_utils.c create mode 100644 tools/lib/mm/file_utils.h diff --git a/MAINTAINERS b/MAINTAINERS index 0f513b42bc18..952e04fcc046 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17135,6 +17135,7 @@ F: mm/memory-tiers.c F: mm/page_idle.c F: mm/pgalloc-track.h F: mm/process_vm_access.c +F: tools/lib/mm/ F: tools/testing/selftests/mm/ MEMORY MANAGEMENT - NUMA MEMBLOCKS AND NUMA EMULATION diff --git a/tools/lib/mm/file_utils.c b/tools/lib/mm/file_utils.c new file mode 100644 index 000000000000..99a153efa8fb --- /dev/null +++ b/tools/lib/mm/file_utils.c @@ -0,0 +1,104 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include + +#include "file_utils.h" + +int read_file(const char *path, char *buf, size_t buflen) +{ + int fd, err; + ssize_t numread; + + fd = open(path, O_RDONLY); + if (fd == -1) + return -errno; + + numread = read(fd, buf, buflen - 1); + if (numread < 1) { + err = numread ? errno : ENODATA; + close(fd); + return -err; + } + + buf[numread] = '\0'; + close(fd); + + return 0; +} + +int write_file(const char *path, const char *buf, size_t buflen) +{ + int fd, saved_errno; + ssize_t numwritten; + + if (buflen < 2) + return -EINVAL; + + fd = open(path, O_WRONLY); + if (fd == -1) + return -errno; + + numwritten = write(fd, buf, buflen - 1); + saved_errno = errno; + close(fd); + + if (numwritten < 0) + return -saved_errno; + + if (numwritten != (ssize_t)(buflen - 1)) + return -EIO; + + return 0; +} + +int read_num(const char *path, unsigned long *num) +{ + unsigned long val; + int ret; + char buf[21]; + char *end; + + if (!num) + return -EINVAL; + + ret = read_file(path, buf, sizeof(buf)); + if (ret) + return ret; + + if (buf[0] < '0' || buf[0] > '9') + return -EINVAL; + + errno = 0; + val = strtoul(buf, &end, 10); + if (errno) + return -errno; + + if (*end == '\n') + end++; + + if (*end != '\0') + return -EINVAL; + + *num = val; + return 0; +} + +int write_num(const char *path, unsigned long num) +{ + char buf[21]; + + sprintf(buf, "%lu", num); + return write_file(path, buf, strlen(buf) + 1); +} + +int write_num_ignore_einval(const char *path, unsigned long num) +{ + int ret; + + ret = write_num(path, num); + return ret == -EINVAL ? 0 : ret; +} diff --git a/tools/lib/mm/file_utils.h b/tools/lib/mm/file_utils.h new file mode 100644 index 000000000000..50daa82c2b2b --- /dev/null +++ b/tools/lib/mm/file_utils.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __MM_FILE_UTILS_H__ +#define __MM_FILE_UTILS_H__ + +#include + +int read_file(const char *path, char *buf, size_t buflen); +int write_file(const char *path, const char *buf, size_t buflen); +int read_num(const char *path, unsigned long *num); +int write_num(const char *path, unsigned long num); +int write_num_ignore_einval(const char *path, unsigned long num); + +#endif diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile index 2d5366196e30..61d974d2cbae 100644 --- a/tools/testing/selftests/mm/Makefile +++ b/tools/testing/selftests/mm/Makefile @@ -37,7 +37,8 @@ endif # LDLIBS. MAKEFLAGS += --no-builtin-rules -CFLAGS = -Wall -O2 -I $(top_srcdir) $(EXTRA_CFLAGS) $(KHDR_INCLUDES) $(TOOLS_INCLUDES) +CFLAGS = -Wall -O2 -I $(top_srcdir) -I $(top_srcdir)/tools/lib +CFLAGS += $(EXTRA_CFLAGS) $(KHDR_INCLUDES) $(TOOLS_INCLUDES) CFLAGS += -Wunreachable-code LDLIBS = -lrt -lpthread -lm @@ -187,8 +188,8 @@ TEST_FILES += write_hugetlb_memory.sh include ../lib.mk -$(TEST_GEN_PROGS): vm_util.c hugepage_settings.c -$(TEST_GEN_FILES): vm_util.c hugepage_settings.c +$(TEST_GEN_PROGS): vm_util.c hugepage_settings.c $(top_srcdir)/tools/lib/mm/file_utils.c +$(TEST_GEN_FILES): vm_util.c hugepage_settings.c $(top_srcdir)/tools/lib/mm/file_utils.c $(OUTPUT)/uffd-stress: uffd-common.c $(OUTPUT)/uffd-unit-tests: uffd-common.c @@ -217,7 +218,7 @@ $(BINARIES_32): CFLAGS += -m32 -mxsave $(BINARIES_32): LDLIBS += -lrt -ldl -lm $(BINARIES_32): $(OUTPUT)/%_32: %.c $(call msg,CC,,$@) - $(Q)$(CC) $(CFLAGS) $(EXTRA_CFLAGS) $(notdir $^) $(LDLIBS) -o $@ + $(Q)$(CC) $(CFLAGS) $(EXTRA_CFLAGS) $^ $(LDLIBS) -o $@ $(foreach t,$(VMTARGETS),$(eval $(call gen-target-rule-32,$(t)))) endif @@ -226,7 +227,7 @@ $(BINARIES_64): CFLAGS += -m64 -mxsave $(BINARIES_64): LDLIBS += -lrt -ldl $(BINARIES_64): $(OUTPUT)/%_64: %.c $(call msg,CC,,$@) - $(Q)$(CC) $(CFLAGS) $(EXTRA_CFLAGS) $(notdir $^) $(LDLIBS) -o $@ + $(Q)$(CC) $(CFLAGS) $(EXTRA_CFLAGS) $^ $(LDLIBS) -o $@ $(foreach t,$(VMTARGETS),$(eval $(call gen-target-rule-64,$(t)))) endif diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c index 6424d798a1d9..4751db798c3a 100644 --- a/tools/testing/selftests/mm/vm_util.c +++ b/tools/testing/selftests/mm/vm_util.c @@ -889,101 +889,6 @@ int unpoison_memory(unsigned long pfn) return ret > 0 ? 0 : -errno; } -int read_file(const char *path, char *buf, size_t buflen) -{ - int fd, err; - ssize_t numread; - - fd = open(path, O_RDONLY); - if (fd == -1) - return -errno; - - numread = read(fd, buf, buflen - 1); - if (numread < 1) { - err = numread ? errno : ENODATA; - close(fd); - return -err; - } - - buf[numread] = '\0'; - close(fd); - - return 0; -} - -int write_file(const char *path, const char *buf, size_t buflen) -{ - int fd, saved_errno; - ssize_t numwritten; - - if (buflen < 2) - return -EINVAL; - - fd = open(path, O_WRONLY); - if (fd == -1) - return -errno; - - numwritten = write(fd, buf, buflen - 1); - saved_errno = errno; - close(fd); - - if (numwritten < 0) - return -saved_errno; - - if (numwritten != (ssize_t)(buflen - 1)) - return -EIO; - - return 0; -} - -int read_num(const char *path, unsigned long *num) -{ - unsigned long val; - int ret; - char buf[21]; - char *end; - - if (!num) - return -EINVAL; - - ret = read_file(path, buf, sizeof(buf)); - if (ret) - return ret; - - if (buf[0] < '0' || buf[0] > '9') - return -EINVAL; - - errno = 0; - val = strtoul(buf, &end, 10); - if (errno) - return -errno; - - if (*end == '\n') - end++; - - if (*end != '\0') - return -EINVAL; - - *num = val; - return 0; -} - -int write_num(const char *path, unsigned long num) -{ - char buf[21]; - - sprintf(buf, "%lu", num); - return write_file(path, buf, strlen(buf) + 1); -} - -int write_num_ignore_einval(const char *path, unsigned long num) -{ - int ret; - - ret = write_num(path, num); - return ret == -EINVAL ? 0 : ret; -} - static unsigned long shmall, shmmax; void __shm_limits_restore(void) diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h index 62f6f5b42649..fe0475f2bdf2 100644 --- a/tools/testing/selftests/mm/vm_util.h +++ b/tools/testing/selftests/mm/vm_util.h @@ -8,6 +8,7 @@ #include /* _SC_PAGESIZE */ #include "kselftest.h" #include +#include #define BIT_ULL(nr) (1ULL << (nr)) #define PM_SOFT_DIRTY BIT_ULL(55) @@ -166,12 +167,6 @@ int unpoison_memory(unsigned long pfn); #define PAGEMAP_PRESENT(ent) (((ent) & (1ull << 63)) != 0) #define PAGEMAP_PFN(ent) ((ent) & ((1ull << 55) - 1)) -int write_file(const char *path, const char *buf, size_t buflen); -int read_file(const char *path, char *buf, size_t buflen); -int read_num(const char *path, unsigned long *num); -int write_num(const char *path, unsigned long num); -int write_num_ignore_einval(const char *path, unsigned long num); - void shm_limits_prepare(unsigned long length); void __shm_limits_restore(void); -- 2.39.5