On 22/02/2021 13:23, Hannes Reinecke wrote:
Hi all,
+
quite some drivers use internal commands for various purposes, most commonly sending TMFs or querying the HBA status. While these commands use the same submission mechanism than normal I/O commands, they will not be counted as outstanding commands, requiring those drivers to implement their own mechanism to figure out outstanding commands. The block layer already has the concept of 'reserved' tags for precisely this purpose, namely non-I/O tags which live off a separate tag pool. That guarantees that these commands can always be sent, and won't be influenced by tag starvation from the I/O tag pool. This patchset enables the use of reserved tags for the SCSI midlayer by allocating a virtual LUN for the HBA itself which just serves as a resource to allocate valid tags from. This removes quite some hacks which were required for some drivers (eg. fnic or snic), and allows the use of tagset iterators within the drivers. The entire patchset can be found at git://git.kernel.org/pub/scm/linux/kernel/git/hare/scsi-devel.git reserved-tags.v7
Thanks for doing this, I'll have a look.
