linux-kernel - [PATCH 1/4] exfat: Simplify exfat_utf8_d

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Date:   Tue, 17 Mar 2020 23:25:52 +0100
From:   Pali Rohár <pali@...nel.org>
To:     Namjae Jeon <namjae.jeon@...sung.com>,
        Sungjong Seo <sj1557.seo@...sung.com>,
        Alexander Viro <viro@...iv.linux.org.uk>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/4] exfat: Simplify exfat_utf8_d_hash() for code points above U+FFFF

Function partial_name_hash() takes long type value into which can be stored
one Unicode code point. Therefore conversion from UTF-32 to UTF-16 is not
needed.

Signed-off-by: Pali Rohár <pali@...nel.org>
---
 fs/exfat/namei.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
index a8681d91f569..e0ec4ff366f5 100644
--- a/fs/exfat/namei.c
+++ b/fs/exfat/namei.c
@@ -147,16 +147,10 @@ static int exfat_utf8_d_hash(const struct dentry *dentry, struct qstr *qstr)
 			return charlen;
 
 		/*
-		 * Convert to UTF-16: code points above U+FFFF are encoded as
-		 * surrogate pairs.
 		 * exfat_toupper() works only for code points up to the U+FFFF.
 		 */
-		if (u > 0xFFFF) {
-			hash = partial_name_hash(exfat_high_surrogate(u), hash);
-			hash = partial_name_hash(exfat_low_surrogate(u), hash);
-		} else {
-			hash = partial_name_hash(exfat_toupper(sb, u), hash);
-		}
+		hash = partial_name_hash(u <= 0xFFFF ? exfat_toupper(sb, u) : u,
+					 hash);
 	}
 
 	qstr->hash = end_name_hash(hash);
-- 
2.20.1