IB/hfi1: Fix an assign/ordering issue with shared context IDs
The current algorithm for generating sub-context IDs is FILO. If the
contexts are not closed in that order, the uniqueness of the ID will be
compromised. I.e. logging the creation/deletion of context IDs with an
application that assigns and closes in a FIFO order reveals:
cache_id: assign: uctxt: 3 sub_ctxt: 0
cache_id: assign: uctxt: 3 sub_ctxt: 1
cache_id: assign: uctxt: 3 sub_ctxt: 2
cache_id: close: uctxt: 3 sub_ctxt: 0
cache_id: assign: uctxt: 3 sub_ctxt: 2 <<<
The sub_ctxt ID 2 is reused incorrectly.
Update the sub-context ID assign algorithm to use a bitmask of in_use
contexts. The new algorithm will allow the contexts to be closed in any
order, and will only re-use unused contexts.
Size subctxt and subctxt_cnt to match the user API size.
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
diff --git a/drivers/infiniband/hw/hfi1/file_ops.c b/drivers/infiniband/hw/hfi1/file_ops.c
index 467f876..9c177ef 100644
--- a/drivers/infiniband/hw/hfi1/file_ops.c
+++ b/drivers/infiniband/hw/hfi1/file_ops.c
@@ -49,6 +49,7 @@
#include <linux/vmalloc.h>
#include <linux/io.h>
#include <linux/sched/mm.h>
+#include <linux/bitmap.h>
#include <rdma/ib.h>
@@ -95,11 +96,10 @@ static int allocate_ctxt(struct hfi1_filedata *fd, struct hfi1_devdata *dd,
struct hfi1_user_info *uinfo);
static unsigned int poll_urgent(struct file *fp, struct poll_table_struct *pt);
static unsigned int poll_next(struct file *fp, struct poll_table_struct *pt);
-static int user_event_ack(struct hfi1_ctxtdata *uctxt, int subctxt,
+static int user_event_ack(struct hfi1_ctxtdata *uctxt, u16 subctxt,
unsigned long events);
-static int set_ctxt_pkey(struct hfi1_ctxtdata *uctxt, unsigned subctxt,
- u16 pkey);
-static int manage_rcvq(struct hfi1_ctxtdata *uctxt, unsigned subctxt,
+static int set_ctxt_pkey(struct hfi1_ctxtdata *uctxt, u16 subctxt, u16 pkey);
+static int manage_rcvq(struct hfi1_ctxtdata *uctxt, u16 subctxt,
int start_stop);
static int vma_fault(struct vm_fault *vmf);
static long hfi1_file_ioctl(struct file *fp, unsigned int cmd,
@@ -773,8 +773,8 @@ static int hfi1_file_close(struct inode *inode, struct file *fp)
HFI1_MAX_SHARED_CTXTS) + fdata->subctxt;
*ev = 0;
- if (--uctxt->cnt) {
- uctxt->active_slaves &= ~(1 << fdata->subctxt);
+ __clear_bit(fdata->subctxt, uctxt->in_use_ctxts);
+ if (!bitmap_empty(uctxt->in_use_ctxts, HFI1_MAX_SHARED_CTXTS)) {
mutex_unlock(&hfi1_mutex);
goto done;
}
@@ -868,7 +868,7 @@ static int assign_ctxt(struct hfi1_filedata *fd, struct hfi1_user_info *uinfo)
}
/*
- * Allocate a base context f context sharing is not required or we
+ * Allocate a base context if context sharing is not required or we
* couldn't find a sub context.
*/
if (!ret)
@@ -905,17 +905,24 @@ static int assign_ctxt(struct hfi1_filedata *fd, struct hfi1_user_info *uinfo)
return ret;
}
+/*
+ * The hfi1_mutex must be held when this function is called. It is
+ * necessary to ensure serialized access to the bitmask in_use_ctxts.
+ */
static int find_sub_ctxt(struct hfi1_filedata *fd,
const struct hfi1_user_info *uinfo)
{
int i;
struct hfi1_devdata *dd = fd->dd;
+ u16 subctxt;
for (i = dd->first_dyn_alloc_ctxt; i < dd->num_rcv_contexts; i++) {
struct hfi1_ctxtdata *uctxt = dd->rcd[i];
/* Skip ctxts which are not yet open */
- if (!uctxt || !uctxt->cnt)
+ if (!uctxt ||
+ bitmap_empty(uctxt->in_use_ctxts,
+ HFI1_MAX_SHARED_CTXTS))
continue;
/* Skip dynamically allocted kernel contexts */
@@ -931,13 +938,19 @@ static int find_sub_ctxt(struct hfi1_filedata *fd,
continue;
/* Verify the sharing process matches the master */
- if (uctxt->userversion != uinfo->userversion ||
- uctxt->cnt >= uctxt->subctxt_cnt) {
+ if (uctxt->userversion != uinfo->userversion)
return -EINVAL;
- }
+
+ /* Find an unused context */
+ subctxt = find_first_zero_bit(uctxt->in_use_ctxts,
+ HFI1_MAX_SHARED_CTXTS);
+ if (subctxt >= uctxt->subctxt_cnt)
+ return -EINVAL;
+
fd->uctxt = uctxt;
- fd->subctxt = uctxt->cnt++;
- uctxt->active_slaves |= 1 << fd->subctxt;
+ fd->subctxt = subctxt;
+ __set_bit(fd->subctxt, uctxt->in_use_ctxts);
+
return 1;
}
@@ -1055,7 +1068,7 @@ static int allocate_ctxt(struct hfi1_filedata *fd, struct hfi1_devdata *dd,
static int init_subctxts(struct hfi1_ctxtdata *uctxt,
const struct hfi1_user_info *uinfo)
{
- unsigned num_subctxts;
+ u16 num_subctxts;
num_subctxts = uinfo->subctxt_cnt;
if (num_subctxts > HFI1_MAX_SHARED_CTXTS)
@@ -1063,7 +1076,6 @@ static int init_subctxts(struct hfi1_ctxtdata *uctxt,
uctxt->subctxt_cnt = uinfo->subctxt_cnt;
uctxt->subctxt_id = uinfo->subctxt_id;
- uctxt->active_slaves = 1;
uctxt->redirect_seq_cnt = 1;
set_bit(HFI1_CTXT_BASE_UNINIT, &uctxt->event_flags);
@@ -1073,7 +1085,7 @@ static int init_subctxts(struct hfi1_ctxtdata *uctxt,
static int setup_subctxt(struct hfi1_ctxtdata *uctxt)
{
int ret = 0;
- unsigned num_subctxts = uctxt->subctxt_cnt;
+ u16 num_subctxts = uctxt->subctxt_cnt;
uctxt->subctxt_uregbase = vmalloc_user(PAGE_SIZE);
if (!uctxt->subctxt_uregbase)
@@ -1425,7 +1437,7 @@ int hfi1_set_uevent_bits(struct hfi1_pportdata *ppd, const int evtbit)
* overflow conditions. start_stop==1 re-enables, to be used to
* re-init the software copy of the head register
*/
-static int manage_rcvq(struct hfi1_ctxtdata *uctxt, unsigned subctxt,
+static int manage_rcvq(struct hfi1_ctxtdata *uctxt, u16 subctxt,
int start_stop)
{
struct hfi1_devdata *dd = uctxt->dd;
@@ -1460,7 +1472,7 @@ static int manage_rcvq(struct hfi1_ctxtdata *uctxt, unsigned subctxt,
* User process then performs actions appropriate to bit having been
* set, if desired, and checks again in future.
*/
-static int user_event_ack(struct hfi1_ctxtdata *uctxt, int subctxt,
+static int user_event_ack(struct hfi1_ctxtdata *uctxt, u16 subctxt,
unsigned long events)
{
int i;
@@ -1481,8 +1493,7 @@ static int user_event_ack(struct hfi1_ctxtdata *uctxt, int subctxt,
return 0;
}
-static int set_ctxt_pkey(struct hfi1_ctxtdata *uctxt, unsigned subctxt,
- u16 pkey)
+static int set_ctxt_pkey(struct hfi1_ctxtdata *uctxt, u16 subctxt, u16 pkey)
{
int ret = -ENOENT, i, intable = 0;
struct hfi1_pportdata *ppd = uctxt->ppd;