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Commit cb886455 authored by Jason Gunthorpe's avatar Jason Gunthorpe Committed by Doug Ledford
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infiniband: Fix alignment of mmap cookies to support VIPT caching 



When vmalloc_user is used to create memory that is supposed to be mmap'd
to user space, it is necessary for the mmap cookie (eg the offset) to be
aligned to SHMLBA.

This creates a situation where all virtual mappings of the same physical
page share the same virtual cache index and guarantees VIPT coherence.
Otherwise the cache is non-coherent and the kernel will not see writes
by userspace when reading the shared page (or vice-versa).

Reported-by: default avatarJosh Beavers <josh.beavers@gmail.com>
Signed-off-by: default avatarJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent 86f46aba

drivers/infiniband/sw/rdmavt/mmap.c

+2 −2
Original line number Diff line number Diff line
@@ -170,9 +170,9 @@ struct rvt_mmap_info *rvt_create_mmap_info(struct rvt_dev_info *rdi, 


	spin_lock_irq(&rdi->mmap_offset_lock);

	if (rdi->mmap_offset == 0)

		rdi->mmap_offset = PAGE_SIZE;

		rdi->mmap_offset = ALIGN(PAGE_SIZE, SHMLBA);

	ip->offset = rdi->mmap_offset;

	rdi->mmap_offset += size;

	rdi->mmap_offset += ALIGN(size, SHMLBA);

	spin_unlock_irq(&rdi->mmap_offset_lock);



	INIT_LIST_HEAD(&ip->pending_mmaps);

drivers/infiniband/sw/rxe/rxe_mmap.c

+2 −2
Original line number Diff line number Diff line
@@ -156,10 +156,10 @@ struct rxe_mmap_info *rxe_create_mmap_info(struct rxe_dev *rxe, 
	spin_lock_bh(&rxe->mmap_offset_lock);



	if (rxe->mmap_offset == 0)

		rxe->mmap_offset = PAGE_SIZE;

		rxe->mmap_offset = ALIGN(PAGE_SIZE, SHMLBA);



	ip->info.offset = rxe->mmap_offset;

	rxe->mmap_offset += size;

	rxe->mmap_offset += ALIGN(size, SHMLBA);



	spin_unlock_bh(&rxe->mmap_offset_lock);