Re: [PATCH 2/2] jffs2: fix buffer dump debug output

From: Cyrille Pitchen
Date: Tue Oct 21 2014 - 05:47:33 EST


Le 21/10/2014 10:17, Joe Perches a écrit :
> On Tue, 2014-10-21 at 10:05 +0200, Cyrille Pitchen wrote:
>> This patch fixes __jffs2_dbg_dump_buffer(): this function prints a message
>> claiming to dump len bytes. However, depending on the start offset, the former
>> code drops up to 31 (JFFS2_BUFDUMP_BYTES_PER_LINE - 1) bytes.
>>
>> Signed-off-by: Cyrille Pitchen <cyrille.pitchen@xxxxxxxxx>
>> ---
>> fs/jffs2/debug.c | 21 ++++++++-------------
>> 1 file changed, 8 insertions(+), 13 deletions(-)
>>
>> diff --git a/fs/jffs2/debug.c b/fs/jffs2/debug.c
>> index 07bd5bc..1b515b2 100644
>> --- a/fs/jffs2/debug.c
>> +++ b/fs/jffs2/debug.c
>> @@ -736,30 +736,25 @@ void
>> __jffs2_dbg_dump_buffer(unsigned char *buf, int len, uint32_t offs)
>> {
>> int skip;
>> - int i;
>> + int i, pos;
>>
>> printk(JFFS2_DBG_MSG_PREFIX " dump from offset %#08x to offset %#08x (%x bytes).\n",
>> offs, offs + len, len);
>> - i = skip = offs % JFFS2_BUFDUMP_BYTES_PER_LINE;
>> + i = skip = offs & (JFFS2_BUFDUMP_BYTES_PER_LINE - 1);
>> offs = offs & ~(JFFS2_BUFDUMP_BYTES_PER_LINE - 1);
>>
>> - if (skip != 0)
>> - printk(JFFS2_DBG "%#08x: ", offs);
>> -
>> + printk(JFFS2_DBG "%#08x: ", offs);
>> while (skip--)
>> printk(" ");
>>
>> - while (i < len) {
>> - if ((i % JFFS2_BUFDUMP_BYTES_PER_LINE) == 0 && i != len -1) {
>> - if (i != 0)
>> - printk("\n");
>> + for (pos = 0; pos < len; ++pos, ++i) {
>> + if (i == JFFS2_BUFDUMP_BYTES_PER_LINE) {
>> offs += JFFS2_BUFDUMP_BYTES_PER_LINE;
>> - printk(JFFS2_DBG "%0#8x: ", offs);
>> + printk(JFFS2_DBG "\n%0#8x: ", offs);
>> + i = 0;
>
> print_hex_dump would be better
>
>
Hi Joe,

thanks for your comment. Indeed using print_hex_dump() would be a good idea
since it would avoid each driver to implement its own version of buffer dumps.
Reading the source code of print_hex_dump(), the output format would change a
little bit:
the output would no longer be aligned to JFFS2_BUFDUMP_BYTES_PER_LINE boundary
using leading spaces.
If it's ok to change the output format it's good for me as well.
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