Messages in this thread | | | Date | Wed, 10 Jun 2015 17:11:00 +0200 | From | Christoph Hellwig <> | Subject | Re: [PATCH v4 2/9] x86: support kmap_atomic_pfn_t() for persistent memory |
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On Wed, Jun 10, 2015 at 11:03:35AM -0400, Matthew Wilcox wrote: > On Wed, Jun 10, 2015 at 02:12:02PM +0200, Christoph Hellwig wrote: > > Btw, I don't think this actually is safe without refcounting your kmap > > structure. > > > > The driver model ->remove callback can be called at any time, which > > will ioremap the memory and remap the kmap structure. But at this > > point a user might still be using it. > > Won't the device data structures be pinned by the refcount on the bdev?
An open filesystem only keeps a reference on the request_queue. The underlying driver model ->remove method will still be called on a surprise removal.
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