The user input to files in the resctrl filesystem are expected to be terminated with a newline. Testing the user input includes a test for the presence of a newline and then replacing the newline with NUL byte followed by comparison using strcmp().
sysfs_streq() exists to test if strings are equal, treating both NUL and newline-then-NUL as equivalent string terminations. Even more, sysfs_match_string() exists to match a given string in an array using sysfs_streq(). Replace existing strcmp() comparisons of strings that are terminated with a newline with more appropriate sysfs_streq() via the sysfs_match_string() API that can perform the match across the different mode strings that are already maintained in an array. Suggested-by: Andy Shevchenko <andriy.shevche...@linux.intel.com> Signed-off-by: Reinette Chatre <reinette.cha...@intel.com> Reviewed-by: Andy Shevchenko <andriy.shevche...@linux.intel.com> --- Changes since V6: - Add Andy's Reviewed-by tag arch/x86/kernel/cpu/resctrl/rdtgroup.c | 28 ++++++++++---------------- 1 file changed, 11 insertions(+), 17 deletions(-) diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c index 25c7379ddb0b..dfd3c6f58901 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -1414,13 +1414,11 @@ static ssize_t rdtgroup_mode_write(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { struct rdtgroup *rdtgrp; - enum rdtgrp_mode mode; int ret = 0; + int user_m; - /* Valid input requires a trailing newline */ - if (nbytes == 0 || buf[nbytes - 1] != '\n') + if (nbytes == 0) return -EINVAL; - buf[nbytes - 1] = '\0'; rdtgrp = rdtgroup_kn_lock_live(of->kn); if (!rdtgrp) { @@ -1430,29 +1428,25 @@ static ssize_t rdtgroup_mode_write(struct kernfs_open_file *of, rdt_last_cmd_clear(); - mode = rdtgrp->mode; + user_m = sysfs_match_string(rdt_mode_str, buf); - if ((!strcmp(buf, "shareable") && mode == RDT_MODE_SHAREABLE) || - (!strcmp(buf, "exclusive") && mode == RDT_MODE_EXCLUSIVE) || - (!strcmp(buf, "pseudo-locksetup") && - mode == RDT_MODE_PSEUDO_LOCKSETUP) || - (!strcmp(buf, "pseudo-locked") && mode == RDT_MODE_PSEUDO_LOCKED)) + /* Do nothing and return success if user asks for current mode */ + if (user_m == rdtgrp->mode) goto out; - if (mode == RDT_MODE_PSEUDO_LOCKED) { + if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED) { rdt_last_cmd_puts("Cannot change pseudo-locked group\n"); ret = -EINVAL; goto out; } - if (!strcmp(buf, "shareable")) { + if (user_m == RDT_MODE_SHAREABLE) { if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) { ret = rdtgroup_locksetup_exit(rdtgrp); if (ret) goto out; } - rdtgrp->mode = RDT_MODE_SHAREABLE; - } else if (!strcmp(buf, "exclusive")) { + } else if (user_m == RDT_MODE_EXCLUSIVE) { if (!rdtgroup_mode_test_exclusive(rdtgrp)) { ret = -EINVAL; goto out; @@ -1462,16 +1456,16 @@ static ssize_t rdtgroup_mode_write(struct kernfs_open_file *of, if (ret) goto out; } - rdtgrp->mode = RDT_MODE_EXCLUSIVE; - } else if (!strcmp(buf, "pseudo-locksetup")) { + } else if (user_m == RDT_MODE_PSEUDO_LOCKSETUP) { ret = rdtgroup_locksetup_enter(rdtgrp); if (ret) goto out; - rdtgrp->mode = RDT_MODE_PSEUDO_LOCKSETUP; } else { rdt_last_cmd_puts("Unknown or unsupported mode\n"); ret = -EINVAL; + goto out; } + rdtgrp->mode = user_m; out: rdtgroup_kn_unlock(of->kn); -- 2.26.2