diff mbox

[4/7] vfs: add the RWF_HIPRI flag for preadv2/pwritev2

Message ID 1456160876-14560-5-git-send-email-hch@lst.de (mailing list archive)
State New, archived
Headers show

Commit Message

Christoph Hellwig Feb. 22, 2016, 5:07 p.m. UTC
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>
---
 fs/read_write.c         | 6 ++++--
 include/linux/fs.h      | 1 +
 include/uapi/linux/fs.h | 3 +++
 3 files changed, 8 insertions(+), 2 deletions(-)

Comments

Jeff Moyer Feb. 26, 2016, 9:56 p.m. UTC | #1
Christoph Hellwig <hch@lst.de> 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 <jmoyer@redhat.com>

>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  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 */
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Christoph Hellwig Feb. 27, 2016, 8:58 a.m. UTC | #2
On Fri, Feb 26, 2016 at 04:56:03PM -0500, Jeff Moyer wrote:
> Christoph Hellwig <hch@lst.de> 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...

I don't really like it too much either.  So if someone else has a better
suggestion: you're welcome!
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diff mbox

Patch

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 */