Messages in this thread | | | Date | Wed, 20 May 2020 00:47:49 +0300 | From | Andy Shevchenko <> | Subject | Re: [PATCH V6 4/4] x86/resctrl: Use appropriate API for strings terminated by newline |
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On Tue, May 19, 2020 at 02:28:31PM -0700, Reinette Chatre wrote: > 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.
FWIW, Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> > --- > Changes since V5: > - Remove the early check of the sysfs_match_string() return code. (Andy) > > 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 088a1536bccc..07e0f150c56e 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); > -- > 2.21.0 >
-- With Best Regards, Andy Shevchenko
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