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RDMA/uverbs: Export XRC domains to user space
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Allow user space to create XRC domains.  Because XRCDs are expected to
be shared among multiple processes, we use inodes to identify an XRCD.

Based on patches by Jack Morgenstein <[email protected]>

Signed-off-by: Sean Hefty <[email protected]>
Signed-off-by: Roland Dreier <[email protected]>
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@shefty @rolandd
shefty authored and rolandd committed Oct 13, 2011
1 parent d3d72d9 commit 53d0bd1
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Showing 6 changed files with 367 additions and 1 deletion.
11 changes: 11 additions & 0 deletions drivers/infiniband/core/uverbs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,8 @@ struct ib_uverbs_device {
struct ib_device *ib_dev;
int devnum;
struct cdev cdev;
struct rb_root xrcd_tree;
struct mutex xrcd_tree_mutex;
};

struct ib_uverbs_event_file {
Expand Down Expand Up @@ -120,6 +122,11 @@ struct ib_uevent_object {
u32 events_reported;
};

struct ib_uxrcd_object {
struct ib_uobject uobject;
atomic_t refcnt;
};

struct ib_uqp_object {
struct ib_uevent_object uevent;
struct list_head mcast_list;
Expand All @@ -142,6 +149,7 @@ extern struct idr ib_uverbs_ah_idr;
extern struct idr ib_uverbs_cq_idr;
extern struct idr ib_uverbs_qp_idr;
extern struct idr ib_uverbs_srq_idr;
extern struct idr ib_uverbs_xrcd_idr;

void idr_remove_uobj(struct idr *idp, struct ib_uobject *uobj);

Expand All @@ -161,6 +169,7 @@ void ib_uverbs_qp_event_handler(struct ib_event *event, void *context_ptr);
void ib_uverbs_srq_event_handler(struct ib_event *event, void *context_ptr);
void ib_uverbs_event_handler(struct ib_event_handler *handler,
struct ib_event *event);
void ib_uverbs_dealloc_xrcd(struct ib_uverbs_device *dev, struct ib_xrcd *xrcd);

#define IB_UVERBS_DECLARE_CMD(name) \
ssize_t ib_uverbs_##name(struct ib_uverbs_file *file, \
Expand Down Expand Up @@ -195,5 +204,7 @@ IB_UVERBS_DECLARE_CMD(create_srq);
IB_UVERBS_DECLARE_CMD(modify_srq);
IB_UVERBS_DECLARE_CMD(query_srq);
IB_UVERBS_DECLARE_CMD(destroy_srq);
IB_UVERBS_DECLARE_CMD(open_xrcd);
IB_UVERBS_DECLARE_CMD(close_xrcd);

#endif /* UVERBS_H */
318 changes: 318 additions & 0 deletions drivers/infiniband/core/uverbs_cmd.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,7 @@ static struct lock_class_key cq_lock_key;
static struct lock_class_key qp_lock_key;
static struct lock_class_key ah_lock_key;
static struct lock_class_key srq_lock_key;
static struct lock_class_key xrcd_lock_key;

#define INIT_UDATA(udata, ibuf, obuf, ilen, olen) \
do { \
Expand Down Expand Up @@ -255,6 +256,18 @@ static void put_srq_read(struct ib_srq *srq)
put_uobj_read(srq->uobject);
}

static struct ib_xrcd *idr_read_xrcd(int xrcd_handle, struct ib_ucontext *context,
struct ib_uobject **uobj)
{
*uobj = idr_read_uobj(&ib_uverbs_xrcd_idr, xrcd_handle, context, 0);
return *uobj ? (*uobj)->object : NULL;
}

static void put_xrcd_read(struct ib_uobject *uobj)
{
put_uobj_read(uobj);
}

ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file,
const char __user *buf,
int in_len, int out_len)
Expand Down Expand Up @@ -298,6 +311,7 @@ ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file,
INIT_LIST_HEAD(&ucontext->qp_list);
INIT_LIST_HEAD(&ucontext->srq_list);
INIT_LIST_HEAD(&ucontext->ah_list);
INIT_LIST_HEAD(&ucontext->xrcd_list);
ucontext->closing = 0;

resp.num_comp_vectors = file->device->num_comp_vectors;
Expand Down Expand Up @@ -579,6 +593,310 @@ ssize_t ib_uverbs_dealloc_pd(struct ib_uverbs_file *file,
return in_len;
}

struct xrcd_table_entry {
struct rb_node node;
struct ib_xrcd *xrcd;
struct inode *inode;
};

static int xrcd_table_insert(struct ib_uverbs_device *dev,
struct inode *inode,
struct ib_xrcd *xrcd)
{
struct xrcd_table_entry *entry, *scan;
struct rb_node **p = &dev->xrcd_tree.rb_node;
struct rb_node *parent = NULL;

entry = kmalloc(sizeof *entry, GFP_KERNEL);
if (!entry)
return -ENOMEM;

entry->xrcd = xrcd;
entry->inode = inode;

while (*p) {
parent = *p;
scan = rb_entry(parent, struct xrcd_table_entry, node);

if (inode < scan->inode) {
p = &(*p)->rb_left;
} else if (inode > scan->inode) {
p = &(*p)->rb_right;
} else {
kfree(entry);
return -EEXIST;
}
}

rb_link_node(&entry->node, parent, p);
rb_insert_color(&entry->node, &dev->xrcd_tree);
igrab(inode);
return 0;
}

static struct xrcd_table_entry *xrcd_table_search(struct ib_uverbs_device *dev,
struct inode *inode)
{
struct xrcd_table_entry *entry;
struct rb_node *p = dev->xrcd_tree.rb_node;

while (p) {
entry = rb_entry(p, struct xrcd_table_entry, node);

if (inode < entry->inode)
p = p->rb_left;
else if (inode > entry->inode)
p = p->rb_right;
else
return entry;
}

return NULL;
}

static struct ib_xrcd *find_xrcd(struct ib_uverbs_device *dev, struct inode *inode)
{
struct xrcd_table_entry *entry;

entry = xrcd_table_search(dev, inode);
if (!entry)
return NULL;

return entry->xrcd;
}

static void xrcd_table_delete(struct ib_uverbs_device *dev,
struct inode *inode)
{
struct xrcd_table_entry *entry;

entry = xrcd_table_search(dev, inode);
if (entry) {
iput(inode);
rb_erase(&entry->node, &dev->xrcd_tree);
kfree(entry);
}
}

ssize_t ib_uverbs_open_xrcd(struct ib_uverbs_file *file,
const char __user *buf, int in_len,
int out_len)
{
struct ib_uverbs_open_xrcd cmd;
struct ib_uverbs_open_xrcd_resp resp;
struct ib_udata udata;
struct ib_uxrcd_object *obj;
struct ib_xrcd *xrcd = NULL;
struct file *f = NULL;
struct inode *inode = NULL;
int ret = 0;
int new_xrcd = 0;

if (out_len < sizeof resp)
return -ENOSPC;

if (copy_from_user(&cmd, buf, sizeof cmd))
return -EFAULT;

INIT_UDATA(&udata, buf + sizeof cmd,
(unsigned long) cmd.response + sizeof resp,
in_len - sizeof cmd, out_len - sizeof resp);

mutex_lock(&file->device->xrcd_tree_mutex);

if (cmd.fd != -1) {
/* search for file descriptor */
f = fget(cmd.fd);
if (!f) {
ret = -EBADF;
goto err_tree_mutex_unlock;
}

inode = f->f_dentry->d_inode;
if (!inode) {
ret = -EBADF;
goto err_tree_mutex_unlock;
}

xrcd = find_xrcd(file->device, inode);
if (!xrcd && !(cmd.oflags & O_CREAT)) {
/* no file descriptor. Need CREATE flag */
ret = -EAGAIN;
goto err_tree_mutex_unlock;
}

if (xrcd && cmd.oflags & O_EXCL) {
ret = -EINVAL;
goto err_tree_mutex_unlock;
}
}

obj = kmalloc(sizeof *obj, GFP_KERNEL);
if (!obj) {
ret = -ENOMEM;
goto err_tree_mutex_unlock;
}

init_uobj(&obj->uobject, 0, file->ucontext, &xrcd_lock_key);

down_write(&obj->uobject.mutex);

if (!xrcd) {
xrcd = file->device->ib_dev->alloc_xrcd(file->device->ib_dev,
file->ucontext, &udata);
if (IS_ERR(xrcd)) {
ret = PTR_ERR(xrcd);
goto err;
}

xrcd->inode = inode;
xrcd->device = file->device->ib_dev;
atomic_set(&xrcd->usecnt, 0);
mutex_init(&xrcd->tgt_qp_mutex);
INIT_LIST_HEAD(&xrcd->tgt_qp_list);
new_xrcd = 1;
}

atomic_set(&obj->refcnt, 0);
obj->uobject.object = xrcd;
ret = idr_add_uobj(&ib_uverbs_xrcd_idr, &obj->uobject);
if (ret)
goto err_idr;

memset(&resp, 0, sizeof resp);
resp.xrcd_handle = obj->uobject.id;

if (inode) {
if (new_xrcd) {
/* create new inode/xrcd table entry */
ret = xrcd_table_insert(file->device, inode, xrcd);
if (ret)
goto err_insert_xrcd;
}
atomic_inc(&xrcd->usecnt);
}

if (copy_to_user((void __user *) (unsigned long) cmd.response,
&resp, sizeof resp)) {
ret = -EFAULT;
goto err_copy;
}

if (f)
fput(f);

mutex_lock(&file->mutex);
list_add_tail(&obj->uobject.list, &file->ucontext->xrcd_list);
mutex_unlock(&file->mutex);

obj->uobject.live = 1;
up_write(&obj->uobject.mutex);

mutex_unlock(&file->device->xrcd_tree_mutex);
return in_len;

err_copy:
if (inode) {
if (new_xrcd)
xrcd_table_delete(file->device, inode);
atomic_dec(&xrcd->usecnt);
}

err_insert_xrcd:
idr_remove_uobj(&ib_uverbs_xrcd_idr, &obj->uobject);

err_idr:
ib_dealloc_xrcd(xrcd);

err:
put_uobj_write(&obj->uobject);

err_tree_mutex_unlock:
if (f)
fput(f);

mutex_unlock(&file->device->xrcd_tree_mutex);

return ret;
}

ssize_t ib_uverbs_close_xrcd(struct ib_uverbs_file *file,
const char __user *buf, int in_len,
int out_len)
{
struct ib_uverbs_close_xrcd cmd;
struct ib_uobject *uobj;
struct ib_xrcd *xrcd = NULL;
struct inode *inode = NULL;
struct ib_uxrcd_object *obj;
int live;
int ret = 0;

if (copy_from_user(&cmd, buf, sizeof cmd))
return -EFAULT;

mutex_lock(&file->device->xrcd_tree_mutex);
uobj = idr_write_uobj(&ib_uverbs_xrcd_idr, cmd.xrcd_handle, file->ucontext);
if (!uobj) {
ret = -EINVAL;
goto out;
}

xrcd = uobj->object;
inode = xrcd->inode;
obj = container_of(uobj, struct ib_uxrcd_object, uobject);
if (atomic_read(&obj->refcnt)) {
put_uobj_write(uobj);
ret = -EBUSY;
goto out;
}

if (!inode || atomic_dec_and_test(&xrcd->usecnt)) {
ret = ib_dealloc_xrcd(uobj->object);
if (!ret)
uobj->live = 0;
}

live = uobj->live;
if (inode && ret)
atomic_inc(&xrcd->usecnt);

put_uobj_write(uobj);

if (ret)
goto out;

if (inode && !live)
xrcd_table_delete(file->device, inode);

idr_remove_uobj(&ib_uverbs_xrcd_idr, uobj);
mutex_lock(&file->mutex);
list_del(&uobj->list);
mutex_unlock(&file->mutex);

put_uobj(uobj);
ret = in_len;

out:
mutex_unlock(&file->device->xrcd_tree_mutex);
return ret;
}

void ib_uverbs_dealloc_xrcd(struct ib_uverbs_device *dev,
struct ib_xrcd *xrcd)
{
struct inode *inode;

inode = xrcd->inode;
if (inode && !atomic_dec_and_test(&xrcd->usecnt))
return;

ib_dealloc_xrcd(xrcd);

if (inode)
xrcd_table_delete(dev, inode);
}

ssize_t ib_uverbs_reg_mr(struct ib_uverbs_file *file,
const char __user *buf, int in_len,
int out_len)
Expand Down
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