From mboxrd@z Thu Jan  1 00:00:00 1970
From: Cyril Hrubis <chrubis@suse.cz>
Date: Fri, 6 Apr 2018 15:02:48 +0200
Subject: [LTP] [PATCH v2 1/2] preadv/preadv03.c: Add new testcase
In-Reply-To: <1523011818-5412-1-git-send-email-yangx.jy@cn.fujitsu.com>
References: <20180405110242.GA22835@rei>
 <1523011818-5412-1-git-send-email-yangx.jy@cn.fujitsu.com>
Message-ID: <20180406130248.GB6328@rei>
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To: ltp@lists.linux.it

Hi!
> +static void setup(void)
> +{
> +	pgsz = getpagesize();
> +	tst_off1 = pgsz;
> +	tst_off2 = pgsz * 3 / 2;
> +	exp_sz1 = pgsz;
> +	exp_sz2 = pgsz / 2;
> +
> +	fd = SAFE_OPEN(FNAME, O_RDWR | O_CREAT | O_DIRECT, 0644);
> +
> +	pop_buf = SAFE_MEMALIGN(pgsz, pgsz);
> +	memset(pop_buf, 0x61, pgsz);
> +	SAFE_WRITE(1, fd, pop_buf, pgsz);
> +
> +	memset(pop_buf, 0x62, pgsz);
> +	SAFE_WRITE(1, fd, pop_buf, pgsz);
> +
> +	rd_iovec = SAFE_MEMALIGN(pgsz, pgsz + sizeof(size_t));
> +	rd_iovec->iov_base = SAFE_MEMALIGN(pgsz, pgsz);
> +	rd_iovec->iov_len = pgsz;

The open(2) manual page says that O_DIRECT buffers should be aligned to
disk block size which can be queried by BLKSSZGET ioctl(). And I suppose
that the offsets should be multiple of the disk block size as well.

> +}
> +
> +static void cleanup(void)
> +{
> +	free(pop_buf);
> +	free(rd_iovec->iov_base);
> +	free(rd_iovec);
> +
> +	if (fd > 0)
> +		SAFE_CLOSE(fd);
> +}

-- 
Cyril Hrubis
chrubis@suse.cz