linux-kernel - Re: [PATCH v1 1/3] misc: fastrpc: Move fdlist to invoke context structure

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Message-ID: <rkwfjphxpnihtiuoyq5cblm5jpep6bnayfv4w2enx2smpnapye@sdvrbndwhq46>
Date: Tue, 2 Sep 2025 07:07:30 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Ekansh Gupta <ekansh.gupta@....qualcomm.com>
Cc: srini@...nel.org, linux-arm-msm@...r.kernel.org,
        gregkh@...uxfoundation.org, quic_bkumar@...cinc.com,
        linux-kernel@...r.kernel.org, quic_chennak@...cinc.com,
        dri-devel@...ts.freedesktop.org, arnd@...db.de
Subject: Re: [PATCH v1 1/3] misc: fastrpc: Move fdlist to invoke context
 structure

On Mon, Sep 01, 2025 at 11:03:34AM +0530, Ekansh Gupta wrote:
> FD list is part of meta buffer which is calculated during put args.
> Move fdlist to invoke context structure for better maintenance and
> to avoid code duplicacy for calculation of critical meta buffer
> contents that are used by fastrpc driver.

Please start with the description of a problem or an issue.

> 
> Signed-off-by: Ekansh Gupta <ekansh.gupta@....qualcomm.com>
> ---
>  drivers/misc/fastrpc.c | 16 +++++-----------
>  1 file changed, 5 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
> index 621bce7e101c..0991ac487192 100644
> --- a/drivers/misc/fastrpc.c
> +++ b/drivers/misc/fastrpc.c
> @@ -233,6 +233,7 @@ struct fastrpc_invoke_ctx {
>  	int pid;
>  	int client_id;
>  	u32 sc;
> +	u64 *fdlist;
>  	u32 *crc;
>  	u64 ctxid;
>  	u64 msg_sz;
> @@ -985,6 +986,7 @@ static int fastrpc_get_args(u32 kernel, struct fastrpc_invoke_ctx *ctx)
>  	rpra = ctx->buf->virt;
>  	list = fastrpc_invoke_buf_start(rpra, ctx->nscalars);
>  	pages = fastrpc_phy_page_start(list, ctx->nscalars);
> +	ctx->fdlist = (u64 *)(pages + ctx->nscalars);
>  	args = (uintptr_t)ctx->buf->virt + metalen;
>  	rlen = pkt_size - metalen;
>  	ctx->rpra = rpra;
> @@ -1087,18 +1089,10 @@ static int fastrpc_put_args(struct fastrpc_invoke_ctx *ctx,
>  	union fastrpc_remote_arg *rpra = ctx->rpra;
>  	struct fastrpc_user *fl = ctx->fl;
>  	struct fastrpc_map *mmap = NULL;
> -	struct fastrpc_invoke_buf *list;
> -	struct fastrpc_phy_page *pages;
> -	u64 *fdlist;
> -	int i, inbufs, outbufs, handles;
> +	int i, inbufs;
>  	int ret = 0;
>  
>  	inbufs = REMOTE_SCALARS_INBUFS(ctx->sc);
> -	outbufs = REMOTE_SCALARS_OUTBUFS(ctx->sc);
> -	handles = REMOTE_SCALARS_INHANDLES(ctx->sc) + REMOTE_SCALARS_OUTHANDLES(ctx->sc);
> -	list = fastrpc_invoke_buf_start(rpra, ctx->nscalars);
> -	pages = fastrpc_phy_page_start(list, ctx->nscalars);
> -	fdlist = (uint64_t *)(pages + inbufs + outbufs + handles);
>  
>  	for (i = inbufs; i < ctx->nbufs; ++i) {
>  		if (!ctx->maps[i]) {
> @@ -1120,9 +1114,9 @@ static int fastrpc_put_args(struct fastrpc_invoke_ctx *ctx,
>  cleanup_fdlist:
>  	/* Clean up fdlist which is updated by DSP */
>  	for (i = 0; i < FASTRPC_MAX_FDLIST; i++) {
> -		if (!fdlist[i])
> +		if (!ctx->fdlist[i])
>  			break;
> -		if (!fastrpc_map_lookup(fl, (int)fdlist[i], &mmap))
> +		if (!fastrpc_map_lookup(fl, (int)ctx->fdlist[i], &mmap))
>  			fastrpc_map_put(mmap);
>  	}
>  
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry