Hello Media Devs!
The patch b2f0d2724ba4: "[media] vcodec: mediatek: Add Mediatek JPEG
Decoder Driver" from Dec 14, 2016, leads to the following Smatch
static checker warning:
drivers/media/platform/mediatek/jpeg/mtk_jpeg_dec_parse.c:140 mtk_jpeg_do_parse()
warn: duplicate check 'notfound' (previous on line 67)
drivers/media/platform/mediatek/jpeg/mtk_jpeg_dec_parse.c
57 static bool mtk_jpeg_do_parse(struct mtk_jpeg_dec_param *param, u8 *src_addr_va,
58 u32 src_size)
59 {
60 bool notfound = true;
61 struct mtk_jpeg_stream stream;
62
63 stream.addr = src_addr_va;
64 stream.size = src_size;
65 stream.curr = 0;
66
67 while (notfound) {
68 int i, length, byte;
69 u32 word;
70
71 byte = read_byte(&stream);
72 if (byte == -1)
73 return false;
74 if (byte != 0xff)
75 continue;
76 do
77 byte = read_byte(&stream);
78 while (byte == 0xff);
79 if (byte == -1)
80 return false;
81 if (byte == 0)
82 continue;
83
84 length = 0;
85 switch (byte) {
86 case SOF0:
87 /* length */
88 if (read_word_be(&stream, &word))
89 break;
90
91 /* precision */
92 if (read_byte(&stream) == -1)
93 break;
94
95 if (read_word_be(&stream, &word))
96 break;
97 param->pic_h = word;
98
99 if (read_word_be(&stream, &word))
100 break;
101 param->pic_w = word;
102
103 param->comp_num = read_byte(&stream);
104 if (param->comp_num != 1 && param->comp_num != 3)
105 break;
106
107 for (i = 0; i < param->comp_num; i++) {
108 param->comp_id[i] = read_byte(&stream);
109 if (param->comp_id[i] == -1)
110 break;
111
112 /* sampling */
113 byte = read_byte(&stream);
114 if (byte == -1)
115 break;
116 param->sampling_w[i] = (byte >> 4) & 0x0F;
117 param->sampling_h[i] = byte & 0x0F;
118
119 param->qtbl_num[i] = read_byte(&stream);
120 if (param->qtbl_num[i] == -1)
121 break;
122 }
123
124 notfound = !(i == param->comp_num);
Should this:
if (i == param->comp_num)
return true;
125 break;
126 case RST ... RST + 7:
127 case SOI:
128 case EOI:
129 case TEM:
130 break;
131 default:
132 if (read_word_be(&stream, &word))
133 break;
134 length = (long)word - 2;
135 read_skip(&stream, length);
136 break;
137 }
138 }
139
--> 140 return !notfound;
We know that "notfound" is false. The double negatives confuse me. I
guess that means it must be found here?
141 }
regards,
dan carpenter
