linux-kernel - Re: [PATCH 2/3] fs/pstore: fs/squashfs: Change lz4 compressor functions to work with new version

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Date:   Thu, 22 Dec 2016 16:31:54 +0100
From:   Sven Schmidt <4sschmid@...ormatik.uni-hamburg.de>
To:     sergey.senozhatsky@...il.com
Cc:     akpm@...ux-foundation.org, bongkyu.kim@....com,
        gregkh@...uxfoundation.org, ccross@...roid.com,
        keescook@...omium.org, anton@...msg.org,
        linux-kernel@...r.kernel.org, tony.luck@...el.com,
        Sven Schmidt <4sschmid@...ormatik.uni-hamburg.de>
Subject: Re: [PATCH 2/3] fs/pstore: fs/squashfs: Change lz4 compressor functions to work with new version

On 12/22/2016 02:21 PM, Sergey Senozhatsky wrote:
> On (12/20/16 19:53), Sven Schmidt wrote:
>> @@ -366,7 +366,7 @@ static int decompress_lz4(void *in, void *out, size_t inlen, size_t outlen)
>>  
>>  static void allocate_lz4(void)
>>  {
>> -	big_oops_buf_sz = lz4_compressbound(psinfo->bufsize);
>> +	big_oops_buf_sz = LZ4_compressBound(psinfo->bufsize);
>>  	big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
>>  	if (big_oops_buf) {
>>  		workspace = kmalloc(LZ4_MEM_COMPRESS, GFP_KERNEL);
>> @@ -493,7 +493,6 @@ static void pstore_dump(struct kmsg_dumper *dumper,
>>  		if (!is_locked) {
>>  			pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
>>  				       , in_nmi() ? "NMI" : why);
>> -			return;
> 
> why did you remove this "failed to lock buf in critical path" return?
> 
> 
>>  		}
>>  	} else {
>>  		spin_lock_irqsave(&psinfo->buf_lock, flags);
>> @@ -585,8 +584,8 @@ static void pstore_console_write(struct console *con, const char *s, unsigned c)
>>  		} else {
>>  			spin_lock_irqsave(&psinfo->buf_lock, flags);
>>  		}
>> -		psinfo->write_buf(PSTORE_TYPE_CONSOLE, 0, &id, 0,
>> -				  s, 0, c, psinfo);
>> +		memcpy(psinfo->buf, s, c);
>> +		psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, 0, c, psinfo);
> 
> why extra memcpy()?
> 
> 	-ss
> 
>>  		spin_unlock_irqrestore(&psinfo->buf_lock, flags);
>>  		s += c;
>>  		c = e - s;
>> diff --git a/fs/squashfs/lz4_wrapper.c b/fs/squashfs/lz4_wrapper.c
>> index ff4468b..c087a63 100644
>> --- a/fs/squashfs/lz4_wrapper.c
>> +++ b/fs/squashfs/lz4_wrapper.c
>> @@ -108,8 +108,7 @@ static int lz4_uncompress(struct squashfs_sb_info *msblk, void *strm,
>>  		put_bh(bh[i]);
>>  	}
>>  
>> -	res = lz4_decompress_unknownoutputsize(stream->input, length,
>> -					stream->output, &dest_len);
>> +	res = LZ4_decompress_safe(stream->input, stream->output, length, (int)dest_len);
>>  	if (res)
>>  		return -EIO;
>

Hey Sergey and thanks for your time. I'm afraid I messed up the diffstat on this.
Actually I just replaced the function calls and corrected the use of return values.
I will send an updated patchset later since there also have been errors
reported from the buildbots.

Sven