Patch "infiniband: Fix alignment of mmap cookies to support VIPT caching" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

infiniband: Fix alignment of mmap cookies to support VIPT caching

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
infiniband-fix-alignment-of-mmap-cookies-to-support-vipt-caching.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jason Gunthorpe <[email protected]>
Date: Fri, 10 Mar 2017 11:34:20 -0700
Subject: infiniband: Fix alignment of mmap cookies to support VIPT caching

From: Jason Gunthorpe <[email protected]>

[ 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).

---
 drivers/infiniband/sw/rdmavt/mmap.c  |    4 ++--
 drivers/infiniband/sw/rxe/rxe_mmap.c |    4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

@@ -170,9 +170,9 @@ struct rvt_mmap_info *rvt_create_mmap_in
 
 	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);

@@ -156,10 +156,10 @@ struct rxe_mmap_info *rxe_create_mmap_in
 	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);
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/infiniband-fix-alignment-of-mmap-cookies-to-support-vipt-caching.patch