cifs: add new function to get unicode string length in bytes

Working in units of words means we do a lot of unnecessary conversion back
and forth. Standardize on bytes instead since that's more useful for
allocating buffers and such. Also, remove hostlen_fromUCS since the new
function has a similar purpose.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>

3 files changed, 35 insertions, 23 deletions

diff --git a/fs/cifs/cifs_unicode.c b/fs/cifs/cifs_unicode.c
index 8389f359b03d..614512573c67 100644
--- a/fs/cifs/cifs_unicode.c
+++ b/fs/cifs/cifs_unicode.c
@@ -26,6 +26,37 @@
 #include "cifs_debug.h"
 
 /*
+ * cifs_ucs2_bytes - how long will a string be after conversion?
+ * @ucs - pointer to input string
+ * @maxbytes - don't go past this many bytes of input string
+ * @codepage - destination codepage
+ *
+ * Walk a ucs2le string and return the number of bytes that the string will
+ * be after being converted to the given charset, not including any null
+ * termination required. Don't walk past maxbytes in the source buffer.
+ */
+int
+cifs_ucs2_bytes(const __le16 *from, int maxbytes,
+                const struct nls_table *codepage)
+{
+        int i;
+        int charlen, outlen = 0;
+        int maxwords = maxbytes / 2;
+        char tmp[NLS_MAX_CHARSET_SIZE];
+
+        for (i = 0; from[i] && i < maxwords; i++) {
+                charlen = codepage->uni2char(le16_to_cpu(from[i]), tmp,
+                                             NLS_MAX_CHARSET_SIZE);
+                if (charlen > 0)
+                        outlen += charlen;
+                else
+                        outlen++;
+        }
+
+        return outlen;
+}
+
+/*
  * cifs_mapchar - convert a little-endian char to proper char in codepage
  * @target - where converted character should be copied
  * @src_char - 2 byte little-endian source character
diff --git a/fs/cifs/cifs_unicode.h b/fs/cifs/cifs_unicode.h
index 6aa6533e49fa..1857f5ff9337 100644
--- a/fs/cifs/cifs_unicode.h
+++ b/fs/cifs/cifs_unicode.h
@@ -74,6 +74,8 @@ extern struct UniCaseRange UniLowerRange[];
 #ifdef __KERNEL__
 int cifs_from_ucs2(char *to, const __le16 *from, int tolen, int fromlen,
                    const struct nls_table *codepage, bool mapchar);
+int cifs_ucs2_bytes(const __le16 *from, int maxbytes,
+                    const struct nls_table *codepage);
 int cifs_strfromUCS_le(char *, const __le16 *, int, const struct nls_table *);
 int cifs_strtoUCS(__le16 *, const char *, int, const struct nls_table *);
 #endif
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index a02c43b3faf5..cadacae46b82 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -3928,27 +3928,6 @@ GetInodeNumOut:
         return rc;
 }
 
-/* computes length of UCS string converted to host codepage
- * @src:        UCS string
- * @maxlen:     length of the input string in UCS characters
- *              (not in bytes)
- *
- * return:      size of input string in host codepage
- */
-static int hostlen_fromUCS(const __le16 *src, const int maxlen,
-                const struct nls_table *nls_codepage) {
-        int i;
-        int hostlen = 0;
-        char to[4];
-        int charlen;
-        for (i = 0; (i < maxlen) && src[i]; ++i) {
-                charlen = nls_codepage->uni2char(le16_to_cpu(src[i]),
-                                to, NLS_MAX_CHARSET_SIZE);
-                hostlen += charlen > 0 ? charlen : 1;
-        }
-        return hostlen;
-}
-
 /* parses DFS refferal V3 structure
  * caller is responsible for freeing target_nodes
  * returns:
@@ -4016,8 +3995,8 @@ parse_DFS_referrals(TRANSACTION2_GET_DFS_REFER_RSP *pSMBr,
                                                 GFP_KERNEL);
                         cifsConvertToUCS((__le16 *) tmp, searchName,
                                         PATH_MAX, nls_codepage, remap);
-                        node->path_consumed = hostlen_fromUCS(tmp,
-                                        le16_to_cpu(pSMBr->PathConsumed)/2,
+                        node->path_consumed = cifs_ucs2_bytes(tmp,
+                                        le16_to_cpu(pSMBr->PathConsumed),
                                         nls_codepage);
                         kfree(tmp);
                 } else