From: Joey Pabalinas <joeypabalinas@gmail.com>
To: longli@microsoft.com
Cc: Steve French <sfrench@samba.org>,
linux-cifs@vger.kernel.org, samba-technical@lists.samba.org,
linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org,
stable@vger.kernel.org, Joey Pabalinas <joeypabalinas@gmail.com>
Subject: Re: [PATCH] CIFS: use the correct length when pinning memory for direct I/O for write
Date: Sun, 16 Dec 2018 15:10:35 -1000 [thread overview]
Message-ID: <20181217011035.ykal46ixowdqyl7h@gmail.com> (raw)
In-Reply-To: <20181216231704.16761-1-longli@linuxonhyperv.com>
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On Sun, Dec 16, 2018 at 11:17:04PM +0000, Long Li wrote:
> From: Long Li <longli@microsoft.com>
>
> The current code attempts to pin memory using the largest possible wsize
> based on the currect SMB credits. This doesn't cause kernel oops but this is
> not optimal as we may pin more pages then actually needed.
>
> Fix this by only pinning what are needed for doing this write I/O.
>
> Signed-off-by: Long Li <longli@microsoft.com>
> Cc: stable@vger.kernel.org
Looks sane to me.
Reviewed-by: Joey Pabalinas <joeypabalinas@gmail.com>
> ---
> fs/cifs/file.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index 3467351..c23bf9d 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -2617,11 +2617,13 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
> if (rc)
> break;
>
> + cur_len = min_t(const size_t, len, wsize);
> +
> if (ctx->direct_io) {
> ssize_t result;
>
> result = iov_iter_get_pages_alloc(
> - from, &pagevec, wsize, &start);
> + from, &pagevec, cur_len, &start);
> if (result < 0) {
> cifs_dbg(VFS,
> "direct_writev couldn't get user pages "
> --
> 2.7.4
>
--
Cheers,
Joey Pabalinas
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next prev parent reply other threads:[~2018-12-17 1:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-16 23:17 [PATCH] CIFS: use the correct length when pinning memory for direct I/O for write Long Li
2018-12-17 1:10 ` Joey Pabalinas [this message]
2018-12-18 5:05 ` Steve French
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