Revert "FROMLIST: misc: fastrpc: Remove buffer from list prior to unmap operation"

This change corresponds to the v4 version shared with the
upstream community.

Revert it to apply the complete v6 revision, which includes additional
fixes and updates not present in the earlier version.

This reverts commit cd522d4.

Signed-off-by: Vinayak Katoch <vkatoch@qti.qualcomm.com>

Author: quic-vkatoch

drivers/misc/fastrpc.c

@@ -2050,6 +2050,9 @@ static int fastrpc_req_munmap_impl(struct fastrpc_user *fl, struct fastrpc_buf *
 				      &args[0]);
 	if (!err) {
 		dev_dbg(dev, "unmmap\tpt 0x%09lx OK\n", buf->raddr);
+		spin_lock(&fl->lock);
+		list_del(&buf->node);
+		spin_unlock(&fl->lock);
 		fastrpc_buf_free(buf);
 	} else {
 		dev_err(dev, "unmmap\tpt 0x%09lx ERROR\n", buf->raddr);
@@ -2063,15 +2066,13 @@ static int fastrpc_req_munmap(struct fastrpc_user *fl, char __user *argp)
 	struct fastrpc_buf *buf = NULL, *iter, *b;
 	struct fastrpc_req_munmap req;
 	struct device *dev = fl->sctx->dev;
-	int err;
 
 	if (copy_from_user(&req, argp, sizeof(req)))
 		return -EFAULT;
 
 	spin_lock(&fl->lock);
 	list_for_each_entry_safe(iter, b, &fl->mmaps, node) {
 		if ((iter->raddr == req.vaddrout) && (iter->size == req.size)) {
-			list_del(&iter->node);
 			buf = iter;
 			break;
 		}
@@ -2084,14 +2085,7 @@ static int fastrpc_req_munmap(struct fastrpc_user *fl, char __user *argp)
 		return -EINVAL;
 	}
 
-	err = fastrpc_req_munmap_impl(fl, buf);
-	if (err) {
-		spin_lock(&fl->lock);
-		list_add_tail(&buf->node, &fl->mmaps);
-		spin_unlock(&fl->lock);
-	}
-
-	return err;
+	return fastrpc_req_munmap_impl(fl, buf);
 }
 
 static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
@@ -2182,17 +2176,14 @@ static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
 
 	if (copy_to_user((void __user *)argp, &req, sizeof(req))) {
 		err = -EFAULT;
-		goto err_copy;
+		goto err_assign;
 	}
 
 	dev_dbg(dev, "mmap\t\tpt 0x%09lx OK [len 0x%08llx]\n",
 		buf->raddr, buf->size);
 
 	return 0;
-err_copy:
-	spin_lock(&fl->lock);
-	list_del(&buf->node);
-	spin_unlock(&fl->lock);
+
 err_assign:
 	fastrpc_req_munmap_impl(fl, buf);