[3.19.y-ckt stable] Patch "IB/qib: Change lkey table allocation to support more MRs" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    IB/qib: Change lkey table allocation to support more MRs

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt8.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 62c41ff658408cf6aee1892bb6f5d74dac2b6ed3 Mon Sep 17 00:00:00 2001
From: Mike Marciniszyn <mike.marciniszyn at intel.com>
Date: Tue, 21 Jul 2015 08:36:07 -0400
Subject: IB/qib: Change lkey table allocation to support more MRs

commit d6f1c17e162b2a11e708f28fa93f2f79c164b442 upstream.

The lkey table is allocated with with a get_user_pages() with an
order based on a number of index bits from a module parameter.

The underlying kernel code cannot allocate that many contiguous pages.

There is no reason the underlying memory needs to be physically
contiguous.

This patch:
- switches the allocation/deallocation to vmalloc/vfree
- caps the number of bits to 23 to insure at least 1 generation bit
  o this matches the module parameter description

Reviewed-by: Vinit Agnihotri <vinit.abhay.agnihotri at intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn at intel.com>
Signed-off-by: Doug Ledford <dledford at redhat.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/infiniband/hw/qib/qib_keys.c  |  4 ++++
 drivers/infiniband/hw/qib/qib_verbs.c | 14 ++++++++++----
 drivers/infiniband/hw/qib/qib_verbs.h |  2 ++
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/hw/qib/qib_keys.c b/drivers/infiniband/hw/qib/qib_keys.c
index 3b9afcc..eabe547 100644
--- a/drivers/infiniband/hw/qib/qib_keys.c
+++ b/drivers/infiniband/hw/qib/qib_keys.c
@@ -86,6 +86,10 @@ int qib_alloc_lkey(struct qib_mregion *mr, int dma_region)
 	 * unrestricted LKEY.
 	 */
 	rkt->gen++;
+	/*
+	 * bits are capped in qib_verbs.c to insure enough bits
+	 * for generation number
+	 */
 	mr->lkey = (r << (32 - ib_qib_lkey_table_size)) |
 		((((1 << (24 - ib_qib_lkey_table_size)) - 1) & rkt->gen)
 		 << 8);
diff --git a/drivers/infiniband/hw/qib/qib_verbs.c b/drivers/infiniband/hw/qib/qib_verbs.c
index 9bcfbd8..40afdfc 100644
--- a/drivers/infiniband/hw/qib/qib_verbs.c
+++ b/drivers/infiniband/hw/qib/qib_verbs.c
@@ -40,6 +40,7 @@
 #include <linux/rculist.h>
 #include <linux/mm.h>
 #include <linux/random.h>
+#include <linux/vmalloc.h>

 #include "qib.h"
 #include "qib_common.h"
@@ -2086,10 +2087,16 @@ int qib_register_ib_device(struct qib_devdata *dd)
 	 * the LKEY).  The remaining bits act as a generation number or tag.
 	 */
 	spin_lock_init(&dev->lk_table.lock);
+	/* insure generation is at least 4 bits see keys.c */
+	if (ib_qib_lkey_table_size > MAX_LKEY_TABLE_BITS) {
+		qib_dev_warn(dd, "lkey bits %u too large, reduced to %u\n",
+			ib_qib_lkey_table_size, MAX_LKEY_TABLE_BITS);
+		ib_qib_lkey_table_size = MAX_LKEY_TABLE_BITS;
+	}
 	dev->lk_table.max = 1 << ib_qib_lkey_table_size;
 	lk_tab_size = dev->lk_table.max * sizeof(*dev->lk_table.table);
 	dev->lk_table.table = (struct qib_mregion __rcu **)
-		__get_free_pages(GFP_KERNEL, get_order(lk_tab_size));
+		vmalloc(lk_tab_size);
 	if (dev->lk_table.table == NULL) {
 		ret = -ENOMEM;
 		goto err_lk;
@@ -2262,7 +2269,7 @@ err_tx:
 					sizeof(struct qib_pio_header),
 				  dev->pio_hdrs, dev->pio_hdrs_phys);
 err_hdrs:
-	free_pages((unsigned long) dev->lk_table.table, get_order(lk_tab_size));
+	vfree(dev->lk_table.table);
 err_lk:
 	kfree(dev->qp_table);
 err_qpt:
@@ -2316,8 +2323,7 @@ void qib_unregister_ib_device(struct qib_devdata *dd)
 					sizeof(struct qib_pio_header),
 				  dev->pio_hdrs, dev->pio_hdrs_phys);
 	lk_tab_size = dev->lk_table.max * sizeof(*dev->lk_table.table);
-	free_pages((unsigned long) dev->lk_table.table,
-		   get_order(lk_tab_size));
+	vfree(dev->lk_table.table);
 	kfree(dev->qp_table);
 }

diff --git a/drivers/infiniband/hw/qib/qib_verbs.h b/drivers/infiniband/hw/qib/qib_verbs.h
index bfc8948..44ca28c 100644
--- a/drivers/infiniband/hw/qib/qib_verbs.h
+++ b/drivers/infiniband/hw/qib/qib_verbs.h
@@ -647,6 +647,8 @@ struct qib_qpn_table {
 	struct qpn_map map[QPNMAP_ENTRIES];
 };

+#define MAX_LKEY_TABLE_BITS 23
+
 struct qib_lkey_table {
 	spinlock_t lock; /* protect changes in this struct */
 	u32 next;               /* next unused index (speeds search) */
--
1.9.1