[PATCH 2/4] exfat: Simplify exfat_utf8_d_cmp() for code points above U+FFFF

From: "Pali Rohár" <pali@kernel.org>
To: Namjae Jeon <namjae.jeon@samsung.com>,
	Sungjong Seo <sj1557.seo@samsung.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 2/4] exfat: Simplify exfat_utf8_d_cmp() for code points above U+FFFF
Date: Tue, 17 Mar 2020 23:25:53 +0100	[thread overview]
Message-ID: <20200317222555.29974-3-pali@kernel.org> (raw)
In-Reply-To: <20200317222555.29974-1-pali@kernel.org>

If two Unicode code points represented in UTF-16 are different then also
their UTF-32 representation must be different. Therefore conversion from
UTF-32 to UTF-16 is not needed.

Signed-off-by: Pali Rohár <pali@kernel.org>
---
 fs/exfat/namei.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
index e0ec4ff366f5..f07cab5fcd28 100644
--- a/fs/exfat/namei.c
+++ b/fs/exfat/namei.c
@@ -179,14 +179,9 @@ static int exfat_utf8_d_cmp(const struct dentry *dentry, unsigned int len,
 		if (u_a <= 0xFFFF && u_b <= 0xFFFF) {
 			if (exfat_toupper(sb, u_a) != exfat_toupper(sb, u_b))
 				return 1;
-		} else if (u_a > 0xFFFF && u_b > 0xFFFF) {
-			if (exfat_low_surrogate(u_a) !=
-					exfat_low_surrogate(u_b) ||
-			    exfat_high_surrogate(u_a) !=
-					exfat_high_surrogate(u_b))
-				return 1;
 		} else {
-			return 1;
+			if (u_a != u_b)
+				return 1;
 		}
 	}
 
-- 
2.20.1

