misc: fastrpc: Free DMA handles for RPC calls with no arguments

The FDs for DMA handles to be freed is updated in fdlist by DSP over
a remote call. This holds true even for remote calls with no
arguments. To handle this, get_args and put_args are needed to
be called for remote calls with no arguments also as fdlist
is allocated in get_args and FDs updated in fdlist is freed
in put_args.

Fixes: 8f6c1d8c4f0c ("misc: fastrpc: Add fdlist implementation")
Cc: stable <stable@kernel.org>
Signed-off-by: Ekansh Gupta <quic_ekangupt@quicinc.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20231013122007.174464-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index fb92197..a52701c 100644 (file)
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -1091,6 +1091,7 @@ static int fastrpc_put_args(struct fastrpc_invoke_ctx *ctx,
                }
        }
 
+       /* Clean up fdlist which is updated by DSP */
        for (i = 0; i < FASTRPC_MAX_FDLIST; i++) {
                if (!fdlist[i])
                        break;
@@ -1157,11 +1158,9 @@ static int fastrpc_internal_invoke(struct fastrpc_user *fl,  u32 kernel,
        if (IS_ERR(ctx))
                return PTR_ERR(ctx);
 
-       if (ctx->nscalars) {
-               err = fastrpc_get_args(kernel, ctx);
-               if (err)
-                       goto bail;
-       }
+       err = fastrpc_get_args(kernel, ctx);
+       if (err)
+               goto bail;
 
        /* make sure that all CPU memory writes are seen by DSP */
        dma_wmb();
@@ -1185,14 +1184,12 @@ static int fastrpc_internal_invoke(struct fastrpc_user *fl,  u32 kernel,
        if (err)
                goto bail;
 
-       if (ctx->nscalars) {
-               /* make sure that all memory writes by DSP are seen by CPU */
-               dma_rmb();
-               /* populate all the output buffers with results */
-               err = fastrpc_put_args(ctx, kernel);
-               if (err)
-                       goto bail;
-       }
+       /* make sure that all memory writes by DSP are seen by CPU */
+       dma_rmb();
+       /* populate all the output buffers with results */
+       err = fastrpc_put_args(ctx, kernel);
+       if (err)
+               goto bail;
 
 bail:
        if (err != -ERESTARTSYS && err != -ETIMEDOUT) {