From: Al Viro <viro@ZenIV.linux.org.uk>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <kafai@fb.com>
Subject: Re: sendfile from 9p fs into af_alg
Date: Wed, 23 Nov 2016 15:53:01 +0000 [thread overview]
Message-ID: <20161123155301.GP1555@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20161123085809.GA46992@ast-mbp.thefacebook.com>
On Wed, Nov 23, 2016 at 12:58:11AM -0800, Alexei Starovoitov wrote:
> if I read it correctly 9p actually responded with 8192 bytes of requests...
> whereas the file size was 9624.
> For large file sizes (in megabytes) the difference between what
> sendfile is reporting and actual file size can be 3x.
> In the small file case (like above dump) it looks rounded to page size for some reason.
OK, I think I see one bug in there; could you check if this gets it back to
normal?
diff --git a/fs/splice.c b/fs/splice.c
index dcaf185..5a7750b 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -408,7 +408,8 @@ static ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
if (res <= 0)
return -ENOMEM;
- nr_pages = res / PAGE_SIZE;
+ BUG_ON(dummy);
+ nr_pages = DIV_ROUND_UP(res, PAGE_SIZE);
vec = __vec;
if (nr_pages > PIPE_DEF_BUFFERS) {
next prev parent reply other threads:[~2016-11-23 15:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-23 3:58 sendfile from 9p fs into af_alg Alexei Starovoitov
2016-11-23 4:46 ` Al Viro
2016-11-23 4:55 ` Alexei Starovoitov
2016-11-23 6:16 ` Al Viro
2016-11-23 8:58 ` Alexei Starovoitov
2016-11-23 15:53 ` Al Viro [this message]
2016-11-23 16:29 ` Alexei Starovoitov
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