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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Shuah Khan , Jonathan Corbet , Jason Gunthorpe , John Hubbard , Peter Xu , Leon Romanovsky , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Mark Brown , Anshuman Khandual , Muhammad Usama Anjum , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Sarthak Sharma Subject: [PATCH v11 2/6] tools/lib/mm: add shared file helpers Date: Fri, 18 Sep 2026 16:52:30 +0530 Message-ID: <20260918112234.195857-3-sarthak.sharma@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260918112234.195857-1-sarthak.sharma@arm.com> References: <20260918112234.195857-1-sarthak.sharma@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 0B17640003 X-Stat-Signature: e37wejjhurxrrhgc493cxbws1thtmi4e X-HE-Tag: 1789730585-716381 X-HE-Meta: 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 iWv5y6EG nMY54Wy3TR8L9byMOVyJ//+fzesS9+TAPUNNs00d2VRhqqoO6HdT+6m1J63LVLVHPgID/WDFe/Hf7sESYD5Anz5VcYlQJGZNlPe1IYWiCX9iQerWofV3aMuV2EryPOqZ3QZ/CsBS1JIa6xVWFz8Br8CJ5A/BNJO6M9507b4Rl7jF1jRCdPHvmcb418XI8ynSeqooDdHTN/ywkgp53HNKUizdcN1vqObZqf6bEyLXSeMcPzvifRg+Nz1B6iMgJGw6fkQ+6VauFN2BI62U= 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. Acked-by: Mike Rapoport (Microsoft) Acked-by: David Hildenbrand (Arm) Tested-by: Muhammad Usama Anjum Signed-off-by: Sarthak Sharma --- MAINTAINERS | 1 + tools/lib/mm/file_utils.c | 106 +++++++++++++++++++++++++++ tools/lib/mm/file_utils.h | 13 ++++ tools/testing/selftests/mm/Makefile | 11 +-- tools/testing/selftests/mm/vm_util.c | 97 ------------------------ tools/testing/selftests/mm/vm_util.h | 7 +- 6 files changed, 127 insertions(+), 108 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 e4412c3d8d45..34f30d072499 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17295,6 +17295,7 @@ 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..9b2237e9823e --- /dev/null +++ b/tools/lib/mm/file_utils.c @@ -0,0 +1,106 @@ +// 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; + + /* Reject signs and leading whitespace that are accepted by strtoul() */ + if (buf[0] < '0' || buf[0] > '9') + return -EINVAL; + + errno = 0; + val = strtoul(buf, &end, 10); + if (errno) + return -errno; + + /* Only allow a newline after the number */ + 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 d3e9bd67904a..c36a9a7089bb 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) $(TOOLS_INCLUDES) CFLAGS += -Wunreachable-code LDLIBS = -lrt -lpthread -lm @@ -184,8 +185,8 @@ TEST_FILES += write_hugetlb_memory.sh include ../lib.mk -$(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 @@ -214,7 +215,7 @@ $(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 @@ -223,7 +224,7 @@ $(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 c1b8d60e519d..4751db798c3a 100644 --- a/tools/testing/selftests/mm/vm_util.c +++ b/tools/testing/selftests/mm/vm_util.c @@ -889,103 +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; - - /* Reject signs and leading whitespace that are accepted by strtoul() */ - if (buf[0] < '0' || buf[0] > '9') - return -EINVAL; - - errno = 0; - val = strtoul(buf, &end, 10); - if (errno) - return -errno; - - /* Only allow a newline after the number */ - 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); -- 2.53.0