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由 Jason Lunz 提交于
Permit lvm to create logical volumes without crashing UML. When device-mapper's DM_DEV_CREATE_CMD ioctl is called to create a new device, dev_create()->dm_create()->alloc_dev()-> blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY) is called. blk_queue_bounce_limit(BLK_BOUNCE_ANY) calls init_emergency_isa_pool() if blk_max_pfn < blk_max_low_pfn. This is the case on UML, but init_emergency_isa_pool() hits BUG_ON(!isa_page_pool) because there doesn't seem to be a dma zone on UML for mempool_create() to allocate from. Most architectures seem to have max_low_pfn == max_pfn, but UML doesn't because of the uml_reserved chunk it keeps for itself. From what I can see, max_pfn and max_low_pfn don't get much use after the bootmem-allocator stops being used anyway, except that they initialize the block layer's blk_max_low_pfn/blk_max_pfn. This ensures init_emergency_isa_pool() doesn't crash uml in this situation by setting max_low_pfn == max_pfn in mem_init(). Signed-off-by: NJason Lunz <lunz@falooley.org> Signed-off-by: NJeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Alasdair G Kergon <agk@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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