vfs: add the RWF_HIPRI flag for preadv2/pwritev2

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.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stephen Bates <stephen.bates@pmcs.com>
Tested-by: Stephen Bates <stephen.bates@pmcs.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Christoph Hellwig
2016-03-03 16:04:01 +01:00
committed by Al Viro
parent 4babf2c5ef
commit 97be7ebe53
3 changed files with 8 additions and 2 deletions

View File

@@ -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)) {