From 3a291c974cf7ffb4fad4df6911b912536e511c9d Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 17 May 2021 20:16:51 -0400 Subject: d_path: saner calling conventions for __dentry_path() 1) lift NUL-termination into the callers 2) pass pointer to the end of buffer instead of that to beginning. (1) allows to simplify dentry_path() - we don't need to play silly games with restoring the leading / of "//deleted" after __dentry_path() would've overwritten it with NUL. We also do not need to check if (either) prepend() in there fails - if the buffer is not large enough, we'll end with negative buflen after prepend() and __dentry_path() will return the right value (ERR_PTR(-ENAMETOOLONG)) just fine. Signed-off-by: Al Viro --- fs/d_path.c | 33 +++++++++++++-------------------- 1 file changed, 13 insertions(+), 20 deletions(-) (limited to 'fs/d_path.c') diff --git a/fs/d_path.c b/fs/d_path.c index 01df5dfa1f88..1a1cf05e7780 100644 --- a/fs/d_path.c +++ b/fs/d_path.c @@ -326,22 +326,21 @@ char *simple_dname(struct dentry *dentry, char *buffer, int buflen) /* * Write full pathname from the root of the filesystem into the buffer. */ -static char *__dentry_path(const struct dentry *d, char *buf, int buflen) +static char *__dentry_path(const struct dentry *d, char *p, int buflen) { const struct dentry *dentry; char *end, *retval; int len, seq = 0; int error = 0; - if (buflen < 2) + if (buflen < 1) goto Elong; rcu_read_lock(); restart: dentry = d; - end = buf + buflen; + end = p; len = buflen; - prepend(&end, &len, "", 1); /* Get '/' right */ retval = end-1; *retval = '/'; @@ -373,27 +372,21 @@ Elong: char *dentry_path_raw(const struct dentry *dentry, char *buf, int buflen) { - return __dentry_path(dentry, buf, buflen); + char *p = buf + buflen; + prepend(&p, &buflen, "", 1); + return __dentry_path(dentry, p, buflen); } EXPORT_SYMBOL(dentry_path_raw); char *dentry_path(const struct dentry *dentry, char *buf, int buflen) { - char *p = NULL; - char *retval; - - if (d_unlinked(dentry)) { - p = buf + buflen; - if (prepend(&p, &buflen, "//deleted", 10) != 0) - goto Elong; - buflen++; - } - retval = __dentry_path(dentry, buf, buflen); - if (!IS_ERR(retval) && p) - *p = '/'; /* restore '/' overriden with '\0' */ - return retval; -Elong: - return ERR_PTR(-ENAMETOOLONG); + char *p = buf + buflen; + + if (unlikely(d_unlinked(dentry))) + prepend(&p, &buflen, "//deleted", 10); + else + prepend(&p, &buflen, "", 1); + return __dentry_path(dentry, p, buflen); } static void get_fs_root_and_pwd_rcu(struct fs_struct *fs, struct path *root, -- cgit