On Sun, 2021-07-11 at 12:40 -0500, Eric Biggers wrote: > Some nits about comments: > > On Fri, Jun 25, 2021 at 09:58:12AM -0400, Jeff Layton wrote: > > diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c > > index 6ca7d16593ff..32b1f50433ba 100644 > > --- a/fs/crypto/fname.c > > +++ b/fs/crypto/fname.c > > @@ -178,10 +178,8 @@ static int fname_decrypt(const struct inode *inode, > > static const char lookup_table[65] = > > "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,"; > > > > -#define BASE64_CHARS(nbytes) DIV_ROUND_UP((nbytes) * 4, 3) > > - > > /** > > - * base64_encode() - base64-encode some bytes > > + * fscrypt_base64_encode() - base64-encode some bytes > > * @src: the bytes to encode > > * @len: number of bytes to encode > > * @dst: (output) the base64-encoded string. Not NUL-terminated. > > * > > * Encodes the input string using characters from the set [A-Za-z0-9+,]. > > * The encoded string is roughly 4/3 times the size of the input string. > > * > > * Return: length of the encoded string > > */ > > -static int base64_encode(const u8 *src, int len, char *dst) > > +int fscrypt_base64_encode(const u8 *src, int len, char *dst) > > As this function will be used more widely, this comment should be fixed to be > more precise. "Roughly 4/3" isn't precise; it's actually exactly > FSCRYPT_BASE64_CHARS(len), right? The following would be better: > > * Encode the input bytes using characters from the set [A-Za-z0-9+,]. > * > * Return: length of the encoded string. This will be equal to > * FSCRYPT_BASE64_CHARS(len). > I'm not certain, but I thought that FSCRYPT_BASE64_CHARS gave you a worst-case estimate of the inflation. This returns the actual length of the resulting encoded string, which may be less than FSCRYPT_BASE64_CHARS(len). > > +/** > > + * fscrypt_base64_decode() - base64-decode some bytes > > + * @src: the bytes to decode > > + * @len: number of bytes to decode > > + * @dst: (output) decoded binary data > > It's a bit confusing to talk about decoding "bytes"; it's really a string. > How about: > > * fscrypt_base64_decode() - base64-decode a string > * @src: the string to decode > * @len: length of the source string, in bytes > * @dst: (output) decoded binary data > * > * Decode a string that was previously encoded using fscrypt_base64_encode(). > * The string doesn't need to be NUL-terminated. > > > + * Return: length of the decoded binary data > > Also the error return values should be documented, e.g.: > > * Return: length of the decoded binary data, or a negative number if the source > * string isn't a valid base64-encoded string. > That update looks reasonable. Thanks, -- Jeff Layton <jlayton@xxxxxxxxxx>
