On 4/10/18 1:01 PM, Rasmus Villemoes wrote:
> On 2018-04-09 20:16, jeffm@xxxxxxxx wrote:
>> From: Jeff Mahoney <jeffm@xxxxxxxx>
>>
>> This patch cleans up the reiserfs print formatting code by getting
>> rid of the do_reiserfs_warning macro. We push the va_list handling
>> and error_buf locking into the caller, which makes prepare_error_buf
>> more like a snprintf routine, so we'll call it that: reiserfs_snprintf.
>>
>>
>> +static DEFINE_SPINLOCK(error_lock);
>> +static char error_buf[2048];
>> +
>> void __reiserfs_warning(struct super_block *sb, const char *id,
>> const char *function, const char *fmt, ...)
>> {
>> - do_reiserfs_warning(fmt);
>> + va_list args;
>> +
>> + va_start(args, fmt);
>> +
>> + spin_lock(&error_lock);
>> + reiserfs_snprintf(error_buf, sizeof(error_buf) - 1, fmt, &args);
>> + spin_unlock(&error_lock);
>> +
>
> Subtracting 1 from the sizeof() is... unusual. Why? snprintf itself
> wants to know the size of the buffer it is printing to, and unless I'm
> misreading your reiserfs_snprintf, that's also what that (and all the
> functions it calls) wants to know.
That's a cut-paste error from an earlier version that did nul
termination differently. I'll fix.
> What is the point of introducing the separate fmt_lock spinlock if it
> will only ever be taken while already holding error_lock?
reiserfs_snprintf is not required to use error_buf anymore. It is
required to use fmt_buf.
-Jeff
--
Jeff Mahoney
SUSE Labs
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