From: Paolo 'Blaisorblade' Giarrusso Date: Tue, 31 Oct 2006 06:07:08 +0000 (-0800) Subject: [PATCH] uml ubd driver: ubd_io_lock usage fixup X-Git-Tag: v2.6.19-rc5~118 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=33f775eea185e8df7701c4afc2c8fcee85c83282;p=pandora-kernel.git [PATCH] uml ubd driver: ubd_io_lock usage fixup Add some comments about requirements for ubd_io_lock and expand its use. When an irq signals that the "controller" (i.e. another thread on the host, which does the actual requests and is the only one blocked on I/O on the host) has done some work, we call again the request function ourselves (do_ubd_request). We now do that with ubd_io_lock held - that's useful to protect against concurrent calls to elv_next_request and so on. XXX: Maybe we shouldn't call at all the request function. Input needed on this. Are we supposed to plug and unplug the queue? That code "indirectly" does that by setting a flag, called do_ubd, which makes the request function return (it's a residual of 2.4 block layer interface). Meanwhile, however, merge this patch, which improves things. Cc: Jens Axboe Signed-off-by: Paolo 'Blaisorblade' Giarrusso Cc: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed