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Re: [Qemu-devel] [PATCH v2] linux-user: Implement copy_file_range
From: |
Laurent Vivier |
Subject: |
Re: [Qemu-devel] [PATCH v2] linux-user: Implement copy_file_range |
Date: |
Thu, 15 Feb 2018 15:31:03 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 |
Le 06/02/2018 à 11:31, Andreas Schwab a écrit :
> No attempt is made to emulate it on the host.
I don't understand what you mean here...
> Signed-off-by: Andreas Schwab <address@hidden>
> ---
> v2: fix spacing
> ---
> linux-user/syscall.c | 39 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 39 insertions(+)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index bed154139e..92b4f59c05 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
...
> +#if defined(TARGET_NR_copy_file_range) && defined(__NR_copy_file_range)
> + case TARGET_NR_copy_file_range:
> + {
> + loff_t inoff, outoff;
> + loff_t *pinoff = NULL, *poutoff = NULL;
> +
> + if (arg2) {
> + if (get_user_u64(inoff, arg2)) {
> + goto efault;
> + }
> + pinoff = &inoff;
> + }
> + if (arg4) {
> + if (get_user_u64(outoff, arg4)) {
> + goto efault;
> + }
> + poutoff = &outoff;
> + }
> + ret = get_errno(safe_copy_file_range(arg1, pinoff, arg3, poutoff,
> + arg5, arg6));
> + if (arg2) {
> + if (put_user_u64(inoff, arg2)) {
> + goto efault;
> + }
> + }
> + if (arg4) {
> + if (put_user_u64(outoff, arg4)) {
> + goto efault;
> + }
> + }
According to the linux implementation, this should be something like:
if (ret > 0) {
if (arg2) {
if (put_user_u64(inoff, arg2)) {
ret = -TARGET_EFAULT;
}
}
if (arg4) {
if (put_user_u64(outoff, arg4)) {
ret = -TARGET_EFAULT;
}
}
}
[TARGET_NR_splice should do this the same way]
Thanks,
Laurent