lkml.org 
[lkml]   [2024]   [Feb]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 2/6] uio_hv_generic: Query the ringbuffer size for device
    On Sat, Feb 17, 2024 at 10:03:36AM -0800, Saurabh Sengar wrote:
    > Query the ring buffer size from pre defined table per device.
    > Keep the size as is if the device doesn't have any preferred
    > ring size.

    What is the "as is" size?

    >
    > Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
    > ---
    > drivers/uio/uio_hv_generic.c | 7 +++++--
    > 1 file changed, 5 insertions(+), 2 deletions(-)
    >
    > diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c
    > index 20d9762331bd..4bda6b52e49e 100644
    > --- a/drivers/uio/uio_hv_generic.c
    > +++ b/drivers/uio/uio_hv_generic.c
    > @@ -238,6 +238,7 @@ hv_uio_probe(struct hv_device *dev,
    > struct hv_uio_private_data *pdata;
    > void *ring_buffer;
    > int ret;
    > + size_t ring_size = hv_dev_ring_size(channel);
    >
    > /* Communicating with host has to be via shared memory not hypercall */
    > if (!channel->offermsg.monitor_allocated) {
    > @@ -245,12 +246,14 @@ hv_uio_probe(struct hv_device *dev,
    > return -ENOTSUPP;
    > }
    >
    > + if (!ring_size)
    > + ring_size = HV_RING_SIZE * PAGE_SIZE;

    Why the magic * PAGE_SIZE here?

    Where is it documented that ring_size is in pages?

    And what happens when PAGE_SIZE is changed? Why are you relying on that
    arbritrary value to dictate your buffer sizes to a device that has
    no relationship with PAGE_SIZE?

    Yes, I know you are copying what was there today, but you have the
    chance to rethink and most importantly, DOCUMENT this decision properly
    now.

    thanks,

    greg k-h

    \
     
     \ /
      Last update: 2024-05-27 15:09    [W:2.473 / U:0.236 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site