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From: Jeya R <jeyr@codeaurora.org>
To: linux-arm-msm@vger.kernel.org, srinivas.kandagatla@linaro.org
Cc: Jeya R <jeyr@codeaurora.org>,
	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
	fastrpc.upstream@qti.qualcomm.com
Subject: [PATCH] misc: fastrpc: copy to user only for non-DMA-BUF heap buffers
Date: Thu, 23 Sep 2021 14:07:52 +0530	[thread overview]
Message-ID: <1632386272-18139-1-git-send-email-jeyr@codeaurora.org> (raw)

fastrpc_put_args is copying all the output buffers to user. For large
number of output context buffers, this might cause performance
degradation. Copying is not needed for DMA-BUF heap buffers.

Signed-off-by: Jeya R <jeyr@codeaurora.org>
---
 drivers/misc/fastrpc.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index beda610..536eabf 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -890,15 +890,17 @@ static int fastrpc_put_args(struct fastrpc_invoke_ctx *ctx,
 	inbufs = REMOTE_SCALARS_INBUFS(ctx->sc);
 
 	for (i = inbufs; i < ctx->nbufs; ++i) {
-		void *src = (void *)(uintptr_t)rpra[i].pv;
-		void *dst = (void *)(uintptr_t)ctx->args[i].ptr;
-		u64 len = rpra[i].len;
+		if (!ctx->maps[i]) {
+			void *src = (void *)(uintptr_t)rpra[i].pv;
+			void *dst = (void *)(uintptr_t)ctx->args[i].ptr;
+			u64 len = rpra[i].len;
 
-		if (!kernel) {
-			if (copy_to_user((void __user *)dst, src, len))
-				return -EFAULT;
-		} else {
-			memcpy(dst, src, len);
+			if (!kernel) {
+				if (copy_to_user((void __user *)dst, src, len))
+					return -EFAULT;
+			} else {
+				memcpy(dst, src, len);
+			}
 		}
 	}
 
-- 
2.7.4


             reply	other threads:[~2021-09-23  8:38 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-23  8:37 Jeya R [this message]
2021-09-23  8:49 ` [PATCH] misc: fastrpc: copy to user only for non-DMA-BUF heap buffers Greg KH
2021-09-23 10:24   ` jeyr
2021-09-23 17:43     ` Greg KH
2021-09-24  6:25       ` jeyr
2021-09-24  6:55         ` Greg KH

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