Re: [PATCH v16 3/5] fpga: image-load: signal eventfd when complete

From: Xu Yilun
Date: Sat Sep 25 2021 - 21:13:16 EST

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In reply to: Russ Weight: "Re: [PATCH v16 3/5] fpga: image-load: signal eventfd when complete"
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On Fri, Sep 24, 2021 at 02:45:57PM -0700, Russ Weight wrote:
>
>
> On 9/24/21 1:49 AM, Xu Yilun wrote:
> > On Wed, Sep 22, 2021 at 05:10:54PM -0700, Russ Weight wrote:
> >> Amend the FPGA_IMAGE_LOAD_WRITE IOCTL implementation to include an
> >> eventfd file descriptor as a parameter. The eventfd will be triggered
> >> when the image upload completes.
> >>
> >> Signed-off-by: Russ Weight <russell.h.weight@xxxxxxxxx>
> >> ---
> >> v16:
> >> - Some cleanup of documentation for the FPGA_IMAGE_LOAD_WRITE IOCTL.
> >> v15:
> >> - This patch is new to the patch-set, and adds an eventfd to the
> >> FPGA_IMAGE_LOAD_WRITE IOCTL. The eventfd is signalled upon completion
> >> of an update.
> >> ---
> >> Documentation/fpga/fpga-image-load.rst | 12 +++++++-----
> >> drivers/fpga/fpga-image-load.c | 22 ++++++++++++++++++++--
> >> include/linux/fpga/fpga-image-load.h | 2 ++
> >> include/uapi/linux/fpga-image-load.h | 3 ++-
> >> 4 files changed, 31 insertions(+), 8 deletions(-)
> >>
> >> diff --git a/Documentation/fpga/fpga-image-load.rst b/Documentation/fpga/fpga-image-load.rst
> >> index ba371c7c0ca0..22a455421bb4 100644
> >> --- a/Documentation/fpga/fpga-image-load.rst
> >> +++ b/Documentation/fpga/fpga-image-load.rst
> >> @@ -27,8 +27,10 @@ ioctl
> >>
> >> FPGA_IMAGE_LOAD_WRITE:
> >>
> >> -Start an image upload with the provided image buffer. This IOCTL returns
> >> -immediately after starting a kernel worker thread to process the image
> >> -upload which could take as long a 40 minutes depending on the actual device
> >> -being updated. This is an exclusive operation; an attempt to start
> >> -concurrent image uploads for the same device will fail with EBUSY.
> >> +Start an image upload with the provided image buffer. This IOCTL returns
> >> +immediately after starting a kernel worker thread to process the image
> >> +upload which could take as long a 40 minutes depending on the actual device
> >> +being updated. This is an exclusive operation; an attempt to start
> > Just curious, there are marks here but seems no change.
> Hmmm - sometimes when fixing up patches, I find it easier to edit
> the patch files (e.g. changing file and symbol names). The patches
> applied cleanly, but I must have forgotten to regenerate them
> before sending them for review.
>
> >
> >> +concurrent image loads for the same device will fail with EBUSY. An eventfd
> > You want to fix "uploads" to "loads"? But there are many other "upload(s)".
> My preference is upload, because load implies more than transferring
> the data but the data transfer is all that this driver really does.
> I preferred fpga_image_load to fpga_image_upload for the device name,
> just because it was a couple of characters less. I'll change "loads"
> to "uploads" here.

That's fine. This word is initiated in Patch #1 and changed in Patch #2,
which makes me wonder why.

>
> Do you think I should rename the driver to fpga_image_upload? Or do
> you think the name is OK if it is probably documented?

The name is OK.

Thanks,
Yilun

>
> - Russ
> >
> > Others look good to me.
> >
> >> +file descriptor parameter is provided to this IOCTL. It will be signalled
> >> +at the completion of the image upload.
> >> diff --git a/drivers/fpga/fpga-image-load.c b/drivers/fpga/fpga-image-load.c
> >> index 65f553b59011..09164a0258a5 100644
> >> --- a/drivers/fpga/fpga-image-load.c
> >> +++ b/drivers/fpga/fpga-image-load.c
> >> @@ -34,6 +34,7 @@ static void fpga_image_prog_complete(struct fpga_image_load *imgld)
> >> {
> >> mutex_lock(&imgld->lock);
> >> imgld->progress = FPGA_IMAGE_PROG_IDLE;
> >> + eventfd_signal(imgld->finished, 1);
> >> mutex_unlock(&imgld->lock);
> >> }
> >>
> >> @@ -112,6 +113,8 @@ static void fpga_image_do_load(struct work_struct *work)
> >> vfree(imgld->data);
> >> imgld->data = NULL;
> >> fpga_image_prog_complete(imgld);
> >> + eventfd_ctx_put(imgld->finished);
> >> + imgld->finished = NULL;
> >> }
> >>
> >> static int fpga_image_load_ioctl_write(struct fpga_image_load *imgld,
> >> @@ -119,6 +122,7 @@ static int fpga_image_load_ioctl_write(struct fpga_image_load *imgld,
> >> {
> >> struct fpga_image_write wb;
> >> unsigned long minsz;
> >> + int ret;
> >> u8 *buf;
> >>
> >> if (imgld->driver_unload || imgld->progress != FPGA_IMAGE_PROG_IDLE)
> >> @@ -135,13 +139,23 @@ static int fpga_image_load_ioctl_write(struct fpga_image_load *imgld,
> >> if (wb.size & 0x3)
> >> return -EINVAL;
> >>
> >> + if (wb.evtfd < 0)
> >> + return -EINVAL;
> >> +
> >> buf = vzalloc(wb.size);
> >> if (!buf)
> >> return -ENOMEM;
> >>
> >> if (copy_from_user(buf, u64_to_user_ptr(wb.buf), wb.size)) {
> >> - vfree(buf);
> >> - return -EFAULT;
> >> + ret = -EFAULT;
> >> + goto exit_free;
> >> + }
> >> +
> >> + imgld->finished = eventfd_ctx_fdget(wb.evtfd);
> >> + if (IS_ERR(imgld->finished)) {
> >> + ret = PTR_ERR(imgld->finished);
> >> + imgld->finished = NULL;
> >> + goto exit_free;
> >> }
> >>
> >> imgld->data = buf;
> >> @@ -151,6 +165,10 @@ static int fpga_image_load_ioctl_write(struct fpga_image_load *imgld,
> >> queue_work(system_unbound_wq, &imgld->work);
> >>
> >> return 0;
> >> +
> >> +exit_free:
> >> + vfree(buf);
> >> + return ret;
> >> }
> >>
> >> static long fpga_image_load_ioctl(struct file *filp, unsigned int cmd,
> >> diff --git a/include/linux/fpga/fpga-image-load.h b/include/linux/fpga/fpga-image-load.h
> >> index 41ab63cf7b20..7d39daa4d921 100644
> >> --- a/include/linux/fpga/fpga-image-load.h
> >> +++ b/include/linux/fpga/fpga-image-load.h
> >> @@ -9,6 +9,7 @@
> >>
> >> #include <linux/cdev.h>
> >> #include <linux/device.h>
> >> +#include <linux/eventfd.h>
> >> #include <linux/mutex.h>
> >> #include <linux/types.h>
> >> #include <uapi/linux/fpga-image-load.h>
> >> @@ -52,6 +53,7 @@ struct fpga_image_load {
> >> u32 progress;
> >> u32 err_code; /* image load error code */
> >> bool driver_unload;
> >> + struct eventfd_ctx *finished;
> >> void *priv;
> >> };
> >>
> >> diff --git a/include/uapi/linux/fpga-image-load.h b/include/uapi/linux/fpga-image-load.h
> >> index 0382078c5a6c..152a8e1c031f 100644
> >> --- a/include/uapi/linux/fpga-image-load.h
> >> +++ b/include/uapi/linux/fpga-image-load.h
> >> @@ -38,7 +38,7 @@
> >> * struct fpga_image_write)
> >> *
> >> * Upload a data buffer to the target device. The user must provide the
> >> - * data buffer and size.
> >> + * data buffer, size, and an eventfd file descriptor.
> >> *
> >> * Return: 0 on success, -errno on failure.
> >> */
> >> @@ -46,6 +46,7 @@ struct fpga_image_write {
> >> /* Input */
> >> __u32 flags; /* Zero for now */
> >> __u32 size; /* Data size (in bytes) to be written */
> >> + __s32 evtfd; /* File descriptor for completion signal */
> >> __u64 buf; /* User space address of source data */
> >> };
> >>
> >> --
> >> 2.25.1

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Previous message: Dave Chinner: "Re: [RFC][PATCH v3 0/9] mm: Use DIO for swap and fix NFS swapfiles"
In reply to: Russ Weight: "Re: [PATCH v16 3/5] fpga: image-load: signal eventfd when complete"
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