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Date:   Fri, 7 Apr 2023 12:32:46 +0300
From:   Mike Rapoport <rppt@linux.ibm.com>
To:     Peter Xu <peterx@redhat.com>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        David Hildenbrand <david@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Axel Rasmussen <axelrasmussen@google.com>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Leonardo Bras Soares Passos <lsoaresp@redhat.com>,
        Mike Rapoport <rppt@linux.vnet.ibm.com>,
        Nadav Amit <nadav.amit@gmail.com>
Subject: Re: [PATCH 09/29] selftests/mm: Reuse pagemap_get_entry() in
 vm_util.h
Message-ID: <ZC/jPr6BXsZR5F4b@linux.ibm.com>
References: <20230330155707.3106228-1-peterx@redhat.com>
 <20230330160711.3106988-1-peterx@redhat.com>
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On Thu, Mar 30, 2023 at 12:07:11PM -0400, Peter Xu wrote:
> Subject: selftests/mm: Reuse pagemap_get_entry() in vm_util.h

Nit: selftests/mm/uffd:

> Meanwhile drop pagemap_read_vaddr().
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>

Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>

> ---
>  tools/testing/selftests/mm/userfaultfd.c | 31 +++++++-----------------
>  1 file changed, 9 insertions(+), 22 deletions(-)
> 
> diff --git a/tools/testing/selftests/mm/userfaultfd.c b/tools/testing/selftests/mm/userfaultfd.c
> index 7e841f7e2884..795fbc4d84f8 100644
> --- a/tools/testing/selftests/mm/userfaultfd.c
> +++ b/tools/testing/selftests/mm/userfaultfd.c
> @@ -1399,19 +1399,6 @@ static int pagemap_open(void)
>  	return fd;
>  }
> 
> -static uint64_t pagemap_read_vaddr(int fd, void *vaddr)
> -{
> -	uint64_t value;
> -	int ret;
> -
> -	ret = pread(fd, &value, sizeof(uint64_t),
> -		    ((uint64_t)vaddr >> 12) * sizeof(uint64_t));
> -	if (ret != sizeof(uint64_t))
> -		err("pread() on pagemap failed");
> -
> -	return value;
> -}
> -
>  /* This macro let __LINE__ works in err() */
>  #define  pagemap_check_wp(value, wp) do {				\
>  		if (!!(value & PM_UFFD_WP) != wp)			\
> @@ -1427,7 +1414,7 @@ static int pagemap_test_fork(bool present)
>  	if (!child) {
>  		/* Open the pagemap fd of the child itself */
>  		fd = pagemap_open();
> -		value = pagemap_read_vaddr(fd, area_dst);
> +		value = pagemap_get_entry(fd, area_dst);
>  		/*
>  		 * After fork() uffd-wp bit should be gone as long as we're
>  		 * without UFFD_FEATURE_EVENT_FORK
> @@ -1446,24 +1433,24 @@ static void userfaultfd_wp_unpopulated_test(int pagemap_fd)
> 
>  	/* Test applying pte marker to anon unpopulated */
>  	wp_range(uffd, (uint64_t)area_dst, page_size, true);
> -	value = pagemap_read_vaddr(pagemap_fd, area_dst);
> +	value = pagemap_get_entry(pagemap_fd, area_dst);
>  	pagemap_check_wp(value, true);
> 
>  	/* Test unprotect on anon pte marker */
>  	wp_range(uffd, (uint64_t)area_dst, page_size, false);
> -	value = pagemap_read_vaddr(pagemap_fd, area_dst);
> +	value = pagemap_get_entry(pagemap_fd, area_dst);
>  	pagemap_check_wp(value, false);
> 
>  	/* Test zap on anon marker */
>  	wp_range(uffd, (uint64_t)area_dst, page_size, true);
>  	if (madvise(area_dst, page_size, MADV_DONTNEED))
>  		err("madvise(MADV_DONTNEED) failed");
> -	value = pagemap_read_vaddr(pagemap_fd, area_dst);
> +	value = pagemap_get_entry(pagemap_fd, area_dst);
>  	pagemap_check_wp(value, false);
> 
>  	/* Test fault in after marker removed */
>  	*area_dst = 1;
> -	value = pagemap_read_vaddr(pagemap_fd, area_dst);
> +	value = pagemap_get_entry(pagemap_fd, area_dst);
>  	pagemap_check_wp(value, false);
>  	/* Drop it to make pte none again */
>  	if (madvise(area_dst, page_size, MADV_DONTNEED))
> @@ -1522,7 +1509,7 @@ static void userfaultfd_pagemap_test(unsigned int test_pgsize)
>  	/* Touch the page */
>  	*area_dst = 1;
>  	wp_range(uffd, (uint64_t)area_dst, test_pgsize, true);
> -	value = pagemap_read_vaddr(pagemap_fd, area_dst);
> +	value = pagemap_get_entry(pagemap_fd, area_dst);
>  	pagemap_check_wp(value, true);
>  	/* Make sure uffd-wp bit dropped when fork */
>  	if (pagemap_test_fork(true))
> @@ -1536,7 +1523,7 @@ static void userfaultfd_pagemap_test(unsigned int test_pgsize)
>  		err("madvise(MADV_PAGEOUT) failed");
> 
>  	/* Uffd-wp should persist even swapped out */
> -	value = pagemap_read_vaddr(pagemap_fd, area_dst);
> +	value = pagemap_get_entry(pagemap_fd, area_dst);
>  	pagemap_check_wp(value, true);
>  	/* Make sure uffd-wp bit dropped when fork */
>  	if (pagemap_test_fork(false))
> @@ -1544,12 +1531,12 @@ static void userfaultfd_pagemap_test(unsigned int test_pgsize)
> 
>  	/* Unprotect; this tests swap pte modifications */
>  	wp_range(uffd, (uint64_t)area_dst, page_size, false);
> -	value = pagemap_read_vaddr(pagemap_fd, area_dst);
> +	value = pagemap_get_entry(pagemap_fd, area_dst);
>  	pagemap_check_wp(value, false);
> 
>  	/* Fault in the page from disk */
>  	*area_dst = 2;
> -	value = pagemap_read_vaddr(pagemap_fd, area_dst);
> +	value = pagemap_get_entry(pagemap_fd, area_dst);
>  	pagemap_check_wp(value, false);
> 
>  	close(pagemap_fd);
> -- 
> 2.39.1
> 

-- 
Sincerely yours,
Mike.