[patch 15/50] IB/srp: Fix FMR mapping for 32-bit kernels and addresses above 4G

[Chris Wright]

-stable review patch.  If anyone has any objections, please let us know.
------------------

From: Roland Dreier <rdreier@xxxxxxxxx>

struct srp_device.fmr_page_mask was unsigned long, which means that
the top part of addresses above 4G was being chopped off on 32-bit
architectures.  Of course nothing good happens when data from SRP
targets is DMAed to the wrong place.

Fix this by changing fmr_page_mask to u64, to match the addresses
actually used by IB devices.

Thanks to Brian Cain <Brian.Cain@xxxxxx> and David McMillen
<davem@xxxxxxxxxxxxxxxxxxxxx> for help diagnosing the bug and testing
the fix.

Signed-off-by: Roland Dreier <rolandd@xxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>
---
I just asked Linus to pull this.  It fixes nasty corruption/crash
problems on 32-bit systems with > 4G of memory.

 drivers/infiniband/ulp/srp/ib_srp.c |    2 +-
 drivers/infiniband/ulp/srp/ib_srp.h |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

--- linux-2.6.19.1.orig/drivers/infiniband/ulp/srp/ib_srp.c
+++ linux-2.6.19.1/drivers/infiniband/ulp/srp/ib_srp.c
@@ -1879,7 +1879,7 @@ static void srp_add_one(struct ib_device
 	 */
 	srp_dev->fmr_page_shift = max(9, ffs(dev_attr->page_size_cap) - 1);
 	srp_dev->fmr_page_size  = 1 << srp_dev->fmr_page_shift;
-	srp_dev->fmr_page_mask  = ~((unsigned long) srp_dev->fmr_page_size - 1);
+	srp_dev->fmr_page_mask  = ~((u64) srp_dev->fmr_page_size - 1);
 
 	INIT_LIST_HEAD(&srp_dev->dev_list);
 
--- linux-2.6.19.1.orig/drivers/infiniband/ulp/srp/ib_srp.h
+++ linux-2.6.19.1/drivers/infiniband/ulp/srp/ib_srp.h
@@ -87,7 +87,7 @@ struct srp_device {
 	struct ib_fmr_pool     *fmr_pool;
 	int			fmr_page_shift;
 	int			fmr_page_size;
-	unsigned long		fmr_page_mask;
+	u64			fmr_page_mask;
 };
 
 struct srp_host {

--
-
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