selftests/vm: write strlen length instead of sizeof to nr_hugepages

When setting back the initial value to nr_hugepages, the
test was writing a length sizeof of the string and checking
that strlen was writen. Since those values are not the same,
use strlen in both place instead.

Also make the error messages more explicit to help in future
debugging.

Signed-off-by: Yannick Brosseau <scientist@fb.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

diff --git a/tools/testing/selftests/vm/compaction_test.c b/tools/testing/selftests/vm/compaction_test.c
index 932ff577ffc0b01405c1a264bbfc36b2baa8c058..6d1437f895b8ea393145eec29c40fd0c10ea1e8a 100644 (file)
--- a/tools/testing/selftests/vm/compaction_test.c
+++ b/tools/testing/selftests/vm/compaction_test.c
@@ -101,7 +101,7 @@ int check_compaction(unsigned long mem_free, unsigned int hugepage_size)
 
        /* Start with the initial condition of 0 huge pages*/
        if (write(fd, "0", sizeof(char)) != sizeof(char)) {
-               perror("Failed to write to /proc/sys/vm/nr_hugepages\n");
+               perror("Failed to write 0 to /proc/sys/vm/nr_hugepages\n");
                goto close_fd;
        }
 
@@ -110,14 +110,14 @@ int check_compaction(unsigned long mem_free, unsigned int hugepage_size)
        /* Request a large number of huge pages. The Kernel will allocate
           as much as it can */
        if (write(fd, "100000", (6*sizeof(char))) != (6*sizeof(char))) {
-               perror("Failed to write to /proc/sys/vm/nr_hugepages\n");
+               perror("Failed to write 100000 to /proc/sys/vm/nr_hugepages\n");
                goto close_fd;
        }
 
        lseek(fd, 0, SEEK_SET);
 
        if (read(fd, nr_hugepages, sizeof(nr_hugepages)) <= 0) {
-               perror("Failed to read from /proc/sys/vm/nr_hugepages\n");
+               perror("Failed to re-read from /proc/sys/vm/nr_hugepages\n");
                goto close_fd;
        }
 
@@ -136,9 +136,9 @@ int check_compaction(unsigned long mem_free, unsigned int hugepage_size)
        printf("No of huge pages allocated = %d\n",
               (atoi(nr_hugepages)));
 
-       if (write(fd, initial_nr_hugepages, sizeof(initial_nr_hugepages))
+       if (write(fd, initial_nr_hugepages, strlen(initial_nr_hugepages))
            != strlen(initial_nr_hugepages)) {
-               perror("Failed to write to /proc/sys/vm/nr_hugepages\n");
+               perror("Failed to write value to /proc/sys/vm/nr_hugepages\n");
                goto close_fd;
        }