On Fri, Mar 20, 2026 at 12:06:54AM +0800, Chunyu Hu wrote: > thp_settings provides write_file() helper for safely writing to a file and > exit when write failure happens. It's a very low level helper and many sub > tests need such a helper, not only thp tests. > > split_huge_page_test also defines a write_file locally. The two have minior > differences in return type and used exit api. And there would be conflicts > if split_huge_page_test wanted to include thp_settings.h because of > different prototype, making it less convenient. > > It's possisble to merge the two, although some tests don't use the > kselftest infrastrucutre for testing. It would also work when using the > ksft_exit_msg() to exit in my test, as the counters are all zero. Output > will be like: > > TAP version 13 > 1..62 > Bail out! /proc/sys/vm/drop_caches1 open failed: No such file or directory > # Totals: pass:0 fail:0 xfail:0 xpass:0 skip:0 error:0 > > So here we just keep the version in split_huge_page_test, and move it into > the vm_util. This makes it easy to maitain and user could just include one > vm_util.h when they don't need thp setting helpers. Keep the prototype of > void return as the function will exit on any error, return value is not > necessary, and will simply the callers like write_num() and write_string(). > > Suggested-by: Mike Rapoport <[email protected]> > Signed-off-by: Chunyu Hu <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]> > --- > Changes in v3: > - make the write_file void return > Changes in v2: > new patch from v2 > --- > .../selftests/mm/split_huge_page_test.c | 15 -------- > tools/testing/selftests/mm/thp_settings.c | 35 ++----------------- > tools/testing/selftests/mm/thp_settings.h | 1 - > tools/testing/selftests/mm/vm_util.c | 15 ++++++++ > tools/testing/selftests/mm/vm_util.h | 2 ++ > 5 files changed, 20 insertions(+), 48 deletions(-) > > diff --git a/tools/testing/selftests/mm/split_huge_page_test.c > b/tools/testing/selftests/mm/split_huge_page_test.c > index e0167111bdd1..93f205327b84 100644 > --- a/tools/testing/selftests/mm/split_huge_page_test.c > +++ b/tools/testing/selftests/mm/split_huge_page_test.c > @@ -255,21 +255,6 @@ static int check_after_split_folio_orders(char > *vaddr_start, size_t len, > return status; > } > > -static void write_file(const char *path, const char *buf, size_t buflen) > -{ > - int fd; > - ssize_t numwritten; > - > - fd = open(path, O_WRONLY); > - if (fd == -1) > - ksft_exit_fail_msg("%s open failed: %s\n", path, > strerror(errno)); > - > - numwritten = write(fd, buf, buflen - 1); > - close(fd); > - if (numwritten < 1) > - ksft_exit_fail_msg("Write failed\n"); > -} > - > static void write_debugfs(const char *fmt, ...) > { > char input[INPUT_MAX]; > diff --git a/tools/testing/selftests/mm/thp_settings.c > b/tools/testing/selftests/mm/thp_settings.c > index 574bd0f8ae48..e748ebfb3d4e 100644 > --- a/tools/testing/selftests/mm/thp_settings.c > +++ b/tools/testing/selftests/mm/thp_settings.c > @@ -6,6 +6,7 @@ > #include <string.h> > #include <unistd.h> > > +#include "vm_util.h" > #include "thp_settings.h" > > #define THP_SYSFS "/sys/kernel/mm/transparent_hugepage/" > @@ -64,29 +65,6 @@ int read_file(const char *path, char *buf, size_t buflen) > return (unsigned int) numread; > } > > -int write_file(const char *path, const char *buf, size_t buflen) > -{ > - int fd; > - ssize_t numwritten; > - > - fd = open(path, O_WRONLY); > - if (fd == -1) { > - printf("open(%s)\n", path); > - exit(EXIT_FAILURE); > - return 0; > - } > - > - numwritten = write(fd, buf, buflen - 1); > - close(fd); > - if (numwritten < 1) { > - printf("write(%s)\n", buf); > - exit(EXIT_FAILURE); > - return 0; > - } > - > - return (unsigned int) numwritten; > -} > - > unsigned long read_num(const char *path) > { > char buf[21]; > @@ -104,10 +82,7 @@ void write_num(const char *path, unsigned long num) > char buf[21]; > > sprintf(buf, "%ld", num); > - if (!write_file(path, buf, strlen(buf) + 1)) { > - perror(path); > - exit(EXIT_FAILURE); > - } > + write_file(path, buf, strlen(buf) + 1); > } > > int thp_read_string(const char *name, const char * const strings[]) > @@ -165,11 +140,7 @@ void thp_write_string(const char *name, const char *val) > printf("%s: Pathname is too long\n", __func__); > exit(EXIT_FAILURE); > } > - > - if (!write_file(path, val, strlen(val) + 1)) { > - perror(path); > - exit(EXIT_FAILURE); > - } > + write_file(path, val, strlen(val) + 1); > } > > unsigned long thp_read_num(const char *name) > diff --git a/tools/testing/selftests/mm/thp_settings.h > b/tools/testing/selftests/mm/thp_settings.h > index 76eeb712e5f1..7748a9009191 100644 > --- a/tools/testing/selftests/mm/thp_settings.h > +++ b/tools/testing/selftests/mm/thp_settings.h > @@ -63,7 +63,6 @@ struct thp_settings { > }; > > int read_file(const char *path, char *buf, size_t buflen); > -int write_file(const char *path, const char *buf, size_t buflen); > unsigned long read_num(const char *path); > void write_num(const char *path, unsigned long num); > > diff --git a/tools/testing/selftests/mm/vm_util.c > b/tools/testing/selftests/mm/vm_util.c > index a6d4ff7dfdc0..ad96d19d1b85 100644 > --- a/tools/testing/selftests/mm/vm_util.c > +++ b/tools/testing/selftests/mm/vm_util.c > @@ -764,3 +764,18 @@ int unpoison_memory(unsigned long pfn) > > return ret > 0 ? 0 : -errno; > } > + > +void write_file(const char *path, const char *buf, size_t buflen) > +{ > + int fd; > + ssize_t numwritten; > + > + fd = open(path, O_WRONLY); > + if (fd == -1) > + ksft_exit_fail_msg("%s open failed: %s\n", path, > strerror(errno)); > + > + numwritten = write(fd, buf, buflen - 1); > + close(fd); > + if (numwritten < 1) > + ksft_exit_fail_msg("Write failed\n"); > +} > diff --git a/tools/testing/selftests/mm/vm_util.h > b/tools/testing/selftests/mm/vm_util.h > index e9c4e24769c1..1a07305ceff4 100644 > --- a/tools/testing/selftests/mm/vm_util.h > +++ b/tools/testing/selftests/mm/vm_util.h > @@ -166,3 +166,5 @@ int unpoison_memory(unsigned long pfn); > > #define PAGEMAP_PRESENT(ent) (((ent) & (1ull << 63)) != 0) > #define PAGEMAP_PFN(ent) ((ent) & ((1ull << 55) - 1)) > + > +void write_file(const char *path, const char *buf, size_t buflen); > -- > 2.53.0 > -- Sincerely yours, Mike.
