IB/hfi1: Fix expected receive setup error exit issues

Fix three error exit issues in expected receive setup.
Re-arrange error exits to increase readability.

Issues and fixes:
1. Possible missed page unpin if tidlist copyout fails and
   not all pinned pages where made part of a TID.
   Fix: Unpin the unused pages.

2. Return success with unset return values tidcnt and length
   when no pages were pinned.
   Fix: Return -ENOSPC if no pages were pinned.

3. Return success with unset return values tidcnt and length when
   no rcvarray entries available.
   Fix: Return -ENOSPC if no rcvarray entries are available.

Fixes: 7e7a436e ("staging/hfi1: Add TID entry program function body")
Fixes: 97736f36 ("IB/hfi1: Validate page aligned for a given virtual addres")
Fixes: f404ca4c ("IB/hfi1: Refactor hfi_user_exp_rcv_setup() IOCTL")
Signed-off-by: Dean Luick <dean.luick@cornelisnetworks.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Link: https://lore.kernel.org/r/167328548150.1472310.1492305874804187634.stgit@awfm-02.cornelisnetworks.comSigned-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/hw/hfi1/user_exp_rcv.c

@@ -268,15 +268,14 @@ int hfi1_user_exp_rcv_setup(struct hfi1_filedata *fd,
 	tidbuf->psets = kcalloc(uctxt->expected_count, sizeof(*tidbuf->psets),
 				GFP_KERNEL);
 	if (!tidbuf->psets) {
-		kfree(tidbuf);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto fail_release_mem;
 	}
 
 	pinned = pin_rcv_pages(fd, tidbuf);
 	if (pinned <= 0) {
-		kfree(tidbuf->psets);
-		kfree(tidbuf);
-		return pinned;
+		ret = (pinned < 0) ? pinned : -ENOSPC;
+		goto fail_unpin;
 	}
 
 	/* Find sets of physically contiguous pages */
@@ -291,14 +290,16 @@ int hfi1_user_exp_rcv_setup(struct hfi1_filedata *fd,
 	fd->tid_used += pageset_count;
 	spin_unlock(&fd->tid_lock);
 
-	if (!pageset_count)
-		goto bail;
+	if (!pageset_count) {
+		ret = -ENOSPC;
+		goto fail_unreserve;
+	}
 
 	ngroups = pageset_count / dd->rcv_entries.group_size;
 	tidlist = kcalloc(pageset_count, sizeof(*tidlist), GFP_KERNEL);
 	if (!tidlist) {
 		ret = -ENOMEM;
-		goto nomem;
+		goto fail_unreserve;
 	}
 
 	tididx = 0;
@@ -394,44 +395,60 @@ int hfi1_user_exp_rcv_setup(struct hfi1_filedata *fd,
 	}
 unlock:
 	mutex_unlock(&uctxt->exp_mutex);
-nomem:
 	hfi1_cdbg(TID, "total mapped: tidpairs:%u pages:%u (%d)", tididx,
 		  mapped_pages, ret);
+
+	/* fail if nothing was programmed, set error if none provided */
+	if (tididx == 0) {
+		if (ret >= 0)
+			ret = -ENOSPC;
+		goto fail_unreserve;
+	}
+
 	/* adjust reserved tid_used to actual count */
 	spin_lock(&fd->tid_lock);
 	fd->tid_used -= pageset_count - tididx;
 	spin_unlock(&fd->tid_lock);
-	if (tididx) {
-		tinfo->tidcnt = tididx;
-		tinfo->length = mapped_pages * PAGE_SIZE;
 
-		if (copy_to_user(u64_to_user_ptr(tinfo->tidlist),
-				 tidlist, sizeof(tidlist[0]) * tididx)) {
-			/*
-			 * On failure to copy to the user level, we need to undo
-			 * everything done so far so we don't leak resources.
-			 */
-			tinfo->tidlist = (unsigned long)&tidlist;
-			hfi1_user_exp_rcv_clear(fd, tinfo);
-			tinfo->tidlist = 0;
-			ret = -EFAULT;
-			goto bail;
-		}
+	/* unpin all pages not covered by a TID */
+	unpin_rcv_pages(fd, tidbuf, NULL, mapped_pages, pinned - mapped_pages,
+			false);
+
+	tinfo->tidcnt = tididx;
+	tinfo->length = mapped_pages * PAGE_SIZE;
+
+	if (copy_to_user(u64_to_user_ptr(tinfo->tidlist),
+			 tidlist, sizeof(tidlist[0]) * tididx)) {
+		ret = -EFAULT;
+		goto fail_unprogram;
 	}
 
-	/*
-	 * If not everything was mapped (due to insufficient RcvArray entries,
-	 * for example), unpin all unmapped pages so we can pin them nex time.
-	 */
-	if (mapped_pages != pinned)
-		unpin_rcv_pages(fd, tidbuf, NULL, mapped_pages,
-				(pinned - mapped_pages), false);
-bail:
+	kfree(tidbuf->pages);
 	kfree(tidbuf->psets);
+	kfree(tidbuf);
 	kfree(tidlist);
+	return 0;
+
+fail_unprogram:
+	/* unprogram, unmap, and unpin all allocated TIDs */
+	tinfo->tidlist = (unsigned long)tidlist;
+	hfi1_user_exp_rcv_clear(fd, tinfo);
+	tinfo->tidlist = 0;
+	pinned = 0;		/* nothing left to unpin */
+	pageset_count = 0;	/* nothing left reserved */
+fail_unreserve:
+	spin_lock(&fd->tid_lock);
+	fd->tid_used -= pageset_count;
+	spin_unlock(&fd->tid_lock);
+fail_unpin:
+	if (pinned > 0)
+		unpin_rcv_pages(fd, tidbuf, NULL, 0, pinned, false);
+fail_release_mem:
 	kfree(tidbuf->pages);
+	kfree(tidbuf->psets);
 	kfree(tidbuf);
-	return ret > 0 ? 0 : ret;
+	kfree(tidlist);
+	return ret;
 }
 
 int hfi1_user_exp_rcv_clear(struct hfi1_filedata *fd,