From: Jason Gunthorpe jgunthorpe@obsidianresearch.com
[ Upstream commit cb8864559631754ac93d5734b165ccd0cad4728c ]
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: Josh Beavers josh.beavers@gmail.com Signed-off-by: Jason Gunthorpe jgunthorpe@obsidianresearch.com Signed-off-by: Doug Ledford dledford@redhat.com Signed-off-by: Sasha Levin alexander.levin@verizon.com --- drivers/infiniband/sw/rdmavt/mmap.c | 4 ++-- drivers/infiniband/sw/rxe/rxe_mmap.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/infiniband/sw/rdmavt/mmap.c b/drivers/infiniband/sw/rdmavt/mmap.c index e202b8142759..6b712eecbd37 100644 --- a/drivers/infiniband/sw/rdmavt/mmap.c +++ b/drivers/infiniband/sw/rdmavt/mmap.c @@ -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); diff --git a/drivers/infiniband/sw/rxe/rxe_mmap.c b/drivers/infiniband/sw/rxe/rxe_mmap.c index c572a4c09359..bd812e00988e 100644 --- a/drivers/infiniband/sw/rxe/rxe_mmap.c +++ b/drivers/infiniband/sw/rxe/rxe_mmap.c @@ -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);