On 08/14/16 10:29, Joe Perches wrote: > On Sun, 2016-08-14 at 17:09 +0000, Bart Van Assche wrote: >> My primary concern is how to enable and disable log messages from user >> space. Many drivers define their own logging macros and export a bitmask >> that allows to enable and disable logging messages per category. These >> bitmask control mechanisms are annoying because figuring out what bit >> controls which message category requires a search through the driver >> source code. I'd like to see all these custom logging macros disappear >> and being replaced by a single mechanism. The "dynamic debug" mechanism >> e.g. is in my opinion much easier to use than the different custom >> logging mechanisms. > > Dynamic debug doesn't have a bitmask function and > still requires looking through the code for lines > and format strings. > > I think you are looking for a system wide equivalent > for the ethtool/netif_<level> mechanism. > > Nothing like that exists currently. > > Some code uses a bitmask/and, other code uses a > level/comparison. > > Care to propose something? Hello Joe, As far as I can see all that the ethtool msglevel API implements is a mechanism to query and set the log level from user space. What various SCSI drivers implement is not a log level but a log mask mechanism. How about the following approach to associate a name with each bit in a log mask, to export these names to user space and to make it possible to enable/disable messages per log category: * Introduce a variant of pr_debug() that allows to specify a textual representation of the log category (a short string without spaces). * Make the log category names available in /sys/kernel/debug/dynamic_debug/... * Today dynamic debug allows to enable/disable log messages by specifying the source file name, function name, line number, module name and/or format string. My proposal is to make it also possible to enable/disable log messages based on the log category name. Anyway, this is just a proposal. Anyone is welcome to come up with an alternative proposal. Bart. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
