On Fri, Apr 10, 2026 at 10:01 AM Jeff Hugo <[email protected]> wrote:
>
> For future reference, $SUBJECT should have a space between "PATCH" and
> the version. git format-patch will do it correctly for you if you use
> the -v option.
>
> On 4/1/2026 4:06 PM, Rosen Penev wrote:
> > Consolidate the two-element allocation into a single allocation using a
> > flexible array member. This reduces memory fragmentation and simplifies
> > the error path by eliminating the need to check for allocation failure
> > between the two allocations.
> >
> > Add __counted_by for runtime bounds checking.
>
> This reword addresses my "why" comment on v1. However I don't see that
> you responded to my question about how this was validated. I don't
> require a v3 of this patch, nor do I really want one. I want you to
> reply to this message and detail what validation you performed on this
> patch.
None. This is a straightforward conversion to a flexible array member
(and future devm_kzalloc_flex).
>
> > Signed-off-by: Rosen Penev <[email protected]>
> > ---
> > v2: use macro for number of elements. reword commit message.
>
> Also for future reference, a blank line to separate the change log from
> the patch diff here makes the change log easier to find and read.
>
> > drivers/accel/qaic/qaic.h | 4 ++--
> > drivers/accel/qaic/qaic_drv.c | 8 +++-----
> > 2 files changed, 5 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/accel/qaic/qaic.h b/drivers/accel/qaic/qaic.h
> > index fa7a8155658c..e237020f6aa9 100644
> > --- a/drivers/accel/qaic/qaic.h
> > +++ b/drivers/accel/qaic/qaic.h
> > @@ -152,8 +152,6 @@ struct qaic_device {
> > struct list_head cntl_xfer_list;
> > /* Synchronizes MHI control device transactions and its xfer list */
> > struct mutex cntl_mutex;
> > - /* Array of DBC struct of this device */
> > - struct dma_bridge_chan *dbc;
> > /* Work queue for tasks related to MHI control device */
> > struct workqueue_struct *cntl_wq;
> > /* Synchronizes all the users of device during cleanup */
> > @@ -206,6 +204,8 @@ struct qaic_device {
> > void *ssr_mhi_buf;
> > /* DBC which is under SSR. Sentinel U32_MAX would mean that no SSR in
> > progress */
> > u32 ssr_dbc;
> > + /* Array of DBC struct of this device */
> > + struct dma_bridge_chan dbc[] __counted_by(num_dbc);
> > };
> >
> > struct qaic_drm_device {
> > diff --git a/drivers/accel/qaic/qaic_drv.c b/drivers/accel/qaic/qaic_drv.c
> > index 63fb8c7b4abc..1dda8dfea5a4 100644
> > --- a/drivers/accel/qaic/qaic_drv.c
> > +++ b/drivers/accel/qaic/qaic_drv.c
> > @@ -43,6 +43,7 @@ MODULE_IMPORT_NS("DMA_BUF");
> > #define QAIC_DESC "Qualcomm Cloud AI Accelerators"
> > #define CNTL_MAJOR 5
> > #define CNTL_MINOR 0
> > +#define DBC_NUM 16
> >
> > struct qaic_device_config {
> > /* Indicates the AIC family the device belongs to */
> > @@ -405,15 +406,12 @@ static struct qaic_device *create_qdev(struct pci_dev
> > *pdev,
> > struct drm_device *drm;
> > int i, ret;
> >
> > - qdev = devm_kzalloc(dev, sizeof(*qdev), GFP_KERNEL);
> > + qdev = devm_kzalloc(dev, struct_size(qdev, dbc, DBC_NUM), GFP_KERNEL);
> > if (!qdev)
> > return NULL;
> >
> > + qdev->num_dbc = DBC_NUM;
> > qdev->dev_state = QAIC_OFFLINE;
> > - qdev->num_dbc = 16;
> > - qdev->dbc = devm_kcalloc(dev, qdev->num_dbc, sizeof(*qdev->dbc),
> > GFP_KERNEL);
> > - if (!qdev->dbc)
> > - return NULL;
> >
> > qddev = devm_drm_dev_alloc(&pdev->dev, &qaic_accel_driver, struct
> > qaic_drm_device, drm);
> > if (IS_ERR(qddev))
> > --
> > 2.53.0
> >
>
