On Wed, 2016-08-17 at 01:19 +0000, Bart Van Assche wrote: > 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. [] > > I think you are looking for a system wide equivalent > > for the ethtool/netif_ mechanism. > > > > Nothing like that exists currently. > > > > Some code uses a bitmask/and, other code uses a > > level/comparison. [] > 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. Many of these logging mechanisms are not just debug facilities. Perhaps a dynamic_debug control would be inappropriate. There have also been various custom scsi log level facilities like the blogic_msg for the very old BusLogic blogic_msg. These functions also sometimes write into some device-specific buffer. Perhaps the largest problem, if this is to be scsi only rather than system wide, is finding out what and how the various bits in a mask should be used. -- 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
