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From:   Abel Vesa <abel.vesa@linaro.org>
To:     Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Amol Maheshwari <amahesh@qti.qualcomm.com>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@somainline.org>,
        Ekansh Gupta <quic_ekagupt@quicinc.com>
Cc:     Rob Herring <robh@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-arm-msm@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        devicetree@vger.kernel.org
Subject: [PATCH v2 06/10] misc: fastrpc: Rework fastrpc_req_munmap
Date:   Fri,  2 Sep 2022 18:48:56 +0300
Message-Id: <20220902154900.3404524-7-abel.vesa@linaro.org>
In-Reply-To: <20220902154900.3404524-1-abel.vesa@linaro.org>
References: <20220902154900.3404524-1-abel.vesa@linaro.org>
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Move the lookup of the munmap request to the fastrpc_req_munmap and pass
on only the buf to the lower level fastrpc_req_munmap_impl. That way
we can use the lower level fastrpc_req_munmap_impl on error path in
fastrpc_req_mmap to free the buf without searching for the munmap
request it belongs to.

Co-developed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
---
 drivers/misc/fastrpc.c | 47 +++++++++++++++++++++---------------------
 1 file changed, 23 insertions(+), 24 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index 5eececd9b6bd..7c364c58e379 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -1630,30 +1630,14 @@ static int fastrpc_get_dsp_info(struct fastrpc_user *fl, char __user *argp)
 	return 0;
 }
 
-static int fastrpc_req_munmap_impl(struct fastrpc_user *fl,
-				   struct fastrpc_req_munmap *req)
+static int fastrpc_req_munmap_impl(struct fastrpc_user *fl, struct fastrpc_buf *buf)
 {
 	struct fastrpc_invoke_args args[1] = { [0] = { 0 } };
-	struct fastrpc_buf *buf = NULL, *iter, *b;
 	struct fastrpc_munmap_req_msg req_msg;
 	struct device *dev = fl->sctx->dev;
 	int err;
 	u32 sc;
 
-	spin_lock(&fl->lock);
-	list_for_each_entry_safe(iter, b, &fl->mmaps, node) {
-		if ((iter->raddr == req->vaddrout) && (iter->size == req->size)) {
-			buf = iter;
-			break;
-		}
-	}
-	spin_unlock(&fl->lock);
-
-	if (!buf) {
-		dev_err(dev, "mmap not in list\n");
-		return -EINVAL;
-	}
-
 	req_msg.pgid = fl->tgid;
 	req_msg.size = buf->size;
 	req_msg.vaddr = buf->raddr;
@@ -1679,12 +1663,29 @@ static int fastrpc_req_munmap_impl(struct fastrpc_user *fl,
 
 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;
 
 	if (copy_from_user(&req, argp, sizeof(req)))
 		return -EFAULT;
 
-	return fastrpc_req_munmap_impl(fl, &req);
+	spin_lock(&fl->lock);
+	list_for_each_entry_safe(iter, b, &fl->mmaps, node) {
+		if ((iter->raddr == req.vaddrout) && (iter->size == req.size)) {
+			buf = iter;
+			break;
+		}
+	}
+	spin_unlock(&fl->lock);
+
+	if (!buf) {
+		dev_err(dev, "mmap\t\tpt 0x%09llx [len 0x%08llx] not in list\n",
+			req.vaddrout, req.size);
+		return -EINVAL;
+	}
+
+	return fastrpc_req_munmap_impl(fl, buf);
 }
 
 static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
@@ -1693,7 +1694,6 @@ static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
 	struct fastrpc_buf *buf = NULL;
 	struct fastrpc_mmap_req_msg req_msg;
 	struct fastrpc_mmap_rsp_msg rsp_msg;
-	struct fastrpc_req_munmap req_unmap;
 	struct fastrpc_phy_page pages;
 	struct fastrpc_req_mmap req;
 	struct device *dev = fl->sctx->dev;
@@ -1755,11 +1755,8 @@ static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
 	spin_unlock(&fl->lock);
 
 	if (copy_to_user((void __user *)argp, &req, sizeof(req))) {
-		/* unmap the memory and release the buffer */
-		req_unmap.vaddrout = buf->raddr;
-		req_unmap.size = buf->size;
-		fastrpc_req_munmap_impl(fl, &req_unmap);
-		return -EFAULT;
+		err = -EFAULT;
+		goto err_assign;
 	}
 
 	dev_dbg(dev, "mmap\t\tpt 0x%09lx OK [len 0x%08llx]\n",
@@ -1767,6 +1764,8 @@ static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
 
 	return 0;
 
+err_assign:
+	fastrpc_req_munmap_impl(fl, buf);
 err_invoke:
 	fastrpc_buf_free(buf);
 
-- 
2.34.1