From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:50829 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752825AbcBZV4F (ORCPT ); Fri, 26 Feb 2016 16:56:05 -0500 From: Jeff Moyer To: Christoph Hellwig Cc: viro@zeniv.linux.org.uk, axboe@fb.com, milosz@adfin.com, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Subject: Re: [PATCH 4/7] vfs: add the RWF_HIPRI flag for preadv2/pwritev2 References: <1456160876-14560-1-git-send-email-hch@lst.de> <1456160876-14560-5-git-send-email-hch@lst.de> Date: Fri, 26 Feb 2016 16:56:03 -0500 In-Reply-To: <1456160876-14560-5-git-send-email-hch@lst.de> (Christoph Hellwig's message of "Mon, 22 Feb 2016 18:07:53 +0100") Message-ID: MIME-Version: 1.0 Content-Type: text/plain Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Christoph Hellwig writes: > This adds a flag that tells the file system that this is a high priority > request for which it's worth to poll the hardware. The flag is purely > advisory and can be ignored if not supported. I'm not in love with the HIGHPRI name, but I don't have a better one in mind. So... Acked-by: Jeff Moyer > > Signed-off-by: Christoph Hellwig > --- > fs/read_write.c | 6 ++++-- > include/linux/fs.h | 1 + > include/uapi/linux/fs.h | 3 +++ > 3 files changed, 8 insertions(+), 2 deletions(-) > > diff --git a/fs/read_write.c b/fs/read_write.c > index 38b9afa..3b3fb22 100644 > --- a/fs/read_write.c > +++ b/fs/read_write.c > @@ -697,10 +697,12 @@ static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter, > struct kiocb kiocb; > ssize_t ret; > > - if (flags) > + if (flags & ~RWF_HIPRI) > return -EOPNOTSUPP; > > init_sync_kiocb(&kiocb, filp); > + if (flags & RWF_HIPRI) > + kiocb.ki_flags |= IOCB_HIPRI; > kiocb.ki_pos = *ppos; > > ret = fn(&kiocb, iter); > @@ -715,7 +717,7 @@ static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter, > { > ssize_t ret = 0; > > - if (flags) > + if (flags & ~RWF_HIPRI) > return -EOPNOTSUPP; > > while (iov_iter_count(iter)) { > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 875277a..a1f731c 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -320,6 +320,7 @@ struct writeback_control; > #define IOCB_EVENTFD (1 << 0) > #define IOCB_APPEND (1 << 1) > #define IOCB_DIRECT (1 << 2) > +#define IOCB_HIPRI (1 << 3) > > struct kiocb { > struct file *ki_filp; > diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h > index 149bec8..d246339 100644 > --- a/include/uapi/linux/fs.h > +++ b/include/uapi/linux/fs.h > @@ -304,4 +304,7 @@ struct fsxattr { > #define SYNC_FILE_RANGE_WRITE 2 > #define SYNC_FILE_RANGE_WAIT_AFTER 4 > > +/* flags for preadv2/pwritev2: */ > +#define RWF_HIPRI 0x00000001 /* high priority request, poll if possible */ > + > #endif /* _UAPI_LINUX_FS_H */