From: Shamir Rabinovitch <shamir.rabinovitch@xxxxxxxxxx>
ufile (&ucontext) with the process who own them must not be released
when there are other ufile (&ucontext) that depens at them.
Signed-off-by: Shamir Rabinovitch <shamir.rabinovitch@xxxxxxxxxx>
Signed-off-by: Shamir Rabinovitch <srabinov7@xxxxxxxxx>
---
drivers/infiniband/core/rdma_core.c | 29 +++++++++++++++++++++++++++
drivers/infiniband/core/uverbs.h | 22 ++++++++++++++++++++
drivers/infiniband/core/uverbs_cmd.c | 16 +++++++++++++++
drivers/infiniband/core/uverbs_main.c | 4 ++++
4 files changed, 71 insertions(+)
diff --git a/drivers/infiniband/core/rdma_core.c b/drivers/infiniband/core/rdma_core.c
index 651625f632d7..c81ff8e28fc6 100644
--- a/drivers/infiniband/core/rdma_core.c
+++ b/drivers/infiniband/core/rdma_core.c
@@ -841,6 +841,33 @@ static void ufile_destroy_ucontext(struct ib_uverbs_file *ufile,
ufile->ucontext = NULL;
}
+static void __uverbs_ufile_refcount(struct ib_uverbs_file *ufile)
+{
+ int wait;
+
+ if (ufile->parent) {
+ pr_debug("%s: release parent ufile. ufile %p parent %p\n",
+ __func__, ufile, ufile->parent);
+ if (atomic_dec_and_test(&ufile->parent->refcount))
+ complete(&ufile->parent->context_released);
+ }
+
+ if (!atomic_dec_and_test(&ufile->refcount)) {
+wait:
+ wait = wait_for_completion_interruptible_timeout(
+ &ufile->context_released, 3*HZ);
+ if (wait == -ERESTARTSYS) {
+ WARN_ONCE(1,
+ "signal while waiting for context release! ufile %p\n",
+ ufile);
+ } else if (wait == 0) {
+ pr_debug("%s: timeout while waiting for context release! ufile %p\n",
+ __func__, ufile);
+ goto wait;
+ }
+ }
+}
+
static int __uverbs_cleanup_ufile(struct ib_uverbs_file *ufile,
enum rdma_remove_reason reason)
{
@@ -923,6 +950,8 @@ void uverbs_destroy_ufile_hw(struct ib_uverbs_file *ufile,
if (!list_empty(&ufile->uobjects))
__uverbs_cleanup_ufile(ufile, reason);
+ __uverbs_ufile_refcount(ufile);
+
ufile_destroy_ucontext(ufile, reason);
done:
diff --git a/drivers/infiniband/core/uverbs.h b/drivers/infiniband/core/uverbs.h
index cf76336cb460..c7e711188567 100644
--- a/drivers/infiniband/core/uverbs.h
+++ b/drivers/infiniband/core/uverbs.h
@@ -165,6 +165,28 @@ struct ib_uverbs_file {
struct xarray idr;
struct file *filp;
+
+ /* context sharing support */
+
+ /*
+ * refcount=1 : zero external context depend on this context
+ * refcount>1 : (refcount-1) external context depend on this context
+ */
+ atomic_t refcount;
+
+ /*
+ * parent =NULL : this context has not imported any objects
+ * parent!=NULL : this context imported objects from parent context
+ */
+ struct ib_uverbs_file *parent;
+
+ /*
+ * context_released completion is signalled by the last
+ * user of this context in case of shared context.
+ * any pre matured release of the context will be delayed
+ * till the last user of this context is gone.
+ */
+ struct completion context_released;
};
struct ib_uverbs_event {
diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index 21f0a1a986f4..8d015587946b 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -3816,6 +3816,10 @@ static int ib_uverbs_import_lock(struct uverbs_attr_bundle *attrs,
struct ib_uverbs_device *fd_dev;
int ret = 0;
+ /* shared context cannot import */
+ if (atomic_read(&file->refcount) > 1)
+ return -EINVAL;
+
*filep = fget(fd);
if (!*filep)
return -EINVAL;
@@ -3829,6 +3833,18 @@ static int ib_uverbs_import_lock(struct uverbs_attr_bundle *attrs,
*ufile = (*filep)->private_data;
fd_dev = (*ufile)->device;
+ if (file->parent) {
+ /* multiple import must use same parent context! */
+ if (file->parent != *ufile) {
+ ret = -EINVAL;
+ goto file;
+ }
+ } else {
+ /* first import must update parent refcount */
+ file->parent = *ufile;
+ atomic_inc(&(*ufile)->refcount);
+ }
+
/* check that both files belong to same ib_device */
if (dev != fd_dev) {
ret = -EINVAL;
diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index fa88a586284c..3c28034a7a9a 100644
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -1081,6 +1081,10 @@ static int ib_uverbs_open(struct inode *inode, struct file *filp)
goto err;
}
+ /* shared context support */
+ atomic_set(&file->refcount, 1);
+ init_completion(&file->context_released);
+
file->device = dev;
kref_init(&file->ref);
mutex_init(&file->ucontext_lock);
--
2.20.1
