IB/ipath: Don't corrupt pending mmap list when unmapped objects are freed

Fix the pending mmap code so it doesn't corrupt the list of pending
mmaps and crash the machine when pending mmaps are destroyed without
first being mapped.  Also, remove an unused variable, and use standard
kernel lists instead of our own homebrewed linked list implementation
to keep the pending mmap list.

Signed-off-by: Robert Walsh <robert.walsh@qlogic.com>
Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 22 insertions, 29 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_cq.c b/drivers/infiniband/hw/ipath/ipath_cq.c
index ea78e6dddc9..4715f89528c 100644
--- a/drivers/infiniband/hw/ipath/ipath_cq.c
+++ b/drivers/infiniband/hw/ipath/ipath_cq.c
@@ -243,33 +243,21 @@ struct ib_cq *ipath_create_cq(struct ib_device *ibdev, int entries,
 	 * See ipath_mmap() for details.
 	 */
 	if (udata && udata->outlen >= sizeof(__u64)) {
-		struct ipath_mmap_info *ip;
-		__u64 offset = (__u64) wc;
 		int err;
+		u32 s = sizeof *wc + sizeof(struct ib_wc) * entries;
 
-		err = ib_copy_to_udata(udata, &offset, sizeof(offset));
-		if (err) {
-			ret = ERR_PTR(err);
+		cq->ip = ipath_create_mmap_info(dev, s, context, wc);
+		if (!cq->ip) {
+			ret = ERR_PTR(-ENOMEM);
 			goto bail_wc;
 		}
 
-		/* Allocate info for ipath_mmap(). */
-		ip = kmalloc(sizeof(*ip), GFP_KERNEL);
-		if (!ip) {
-			ret = ERR_PTR(-ENOMEM);
-			goto bail_wc;
+		err = ib_copy_to_udata(udata, &cq->ip->offset,
+				       sizeof(cq->ip->offset));
+		if (err) {
+			ret = ERR_PTR(err);
+			goto bail_ip;
 		}
-		cq->ip = ip;
-		ip->context = context;
-		ip->obj = wc;
-		kref_init(&ip->ref);
-		ip->mmap_cnt = 0;
-		ip->size = PAGE_ALIGN(sizeof(*wc) +
-				      sizeof(struct ib_wc) * entries);
-		spin_lock_irq(&dev->pending_lock);
-		ip->next = dev->pending_mmaps;
-		dev->pending_mmaps = ip;
-		spin_unlock_irq(&dev->pending_lock);
 	} else
 		cq->ip = NULL;
 
@@ -277,12 +265,18 @@ struct ib_cq *ipath_create_cq(struct ib_device *ibdev, int entries,
 	if (dev->n_cqs_allocated == ib_ipath_max_cqs) {
 		spin_unlock(&dev->n_cqs_lock);
 		ret = ERR_PTR(-ENOMEM);
-		goto bail_wc;
+		goto bail_ip;
 	}
 
 	dev->n_cqs_allocated++;
 	spin_unlock(&dev->n_cqs_lock);
 
+	if (cq->ip) {
+		spin_lock_irq(&dev->pending_lock);
+		list_add(&cq->ip->pending_mmaps, &dev->pending_mmaps);
+		spin_unlock_irq(&dev->pending_lock);
+	}
+
 	/*
 	 * ib_create_cq() will initialize cq->ibcq except for cq->ibcq.cqe.
 	 * The number of entries should be >= the number requested or return
@@ -301,12 +295,12 @@ struct ib_cq *ipath_create_cq(struct ib_device *ibdev, int entries,
 
 	goto done;
 
+bail_ip:
+	kfree(cq->ip);
 bail_wc:
 	vfree(wc);
-
 bail_cq:
 	kfree(cq);
-
 done:
 	return ret;
 }
@@ -443,13 +437,12 @@ int ipath_resize_cq(struct ib_cq *ibcq, int cqe, struct ib_udata *udata)
 	if (cq->ip) {
 		struct ipath_ibdev *dev = to_idev(ibcq->device);
 		struct ipath_mmap_info *ip = cq->ip;
+		u32 s = sizeof *wc + sizeof(struct ib_wc) * cqe;
 
-		ip->obj = wc;
-		ip->size = PAGE_ALIGN(sizeof(*wc) +
-				      sizeof(struct ib_wc) * cqe);
+		ipath_update_mmap_info(dev, ip, s, wc);
 		spin_lock_irq(&dev->pending_lock);
-		ip->next = dev->pending_mmaps;
-		dev->pending_mmaps = ip;
+		if (list_empty(&ip->pending_mmaps))
+			list_add(&ip->pending_mmaps, &dev->pending_mmaps);
 		spin_unlock_irq(&dev->pending_lock);
 	}