Re: [PATCH V2 05/11] remoteproc: qcom_q6v5_mss: revert "map/unmap metadata region before/after use"

[Manivannan Sadhasivam]

On Mon, Jan 09, 2023 at 03:30:22PM +0530, Sibi Sankar wrote:
> Hey Mani,
> Thanks for taking time to review the series.
> 
> On 1/9/23 13:48, Manivannan Sadhasivam wrote:
> > + Christoph
> > 
> > Hi Sibi,
> > 
> > On Mon, Jan 09, 2023 at 09:18:37AM +0530, Sibi Sankar wrote:
> > > This reverts commit fc156629b23a21181e473e60341e3a78af25a1d4.
> > > 
> > > The memory region allocated using dma_alloc_attr with no kernel mapping
> > > attribute set would still be a part of the linear kernel map. Hence as a
> > > precursor to using reserved memory for modem metadata region, revert back
> > > to the simpler way of dynamic memory allocation.
> > > 
> > > Suggested-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> > > Signed-off-by: Sibi Sankar <quic_sibis@xxxxxxxxxxx>
> > 
> > Christoph already submitted a patch that reverts fc156629b23a:
> > https://lore.kernel.org/linux-arm-msm/20221223092703.61927-2-hch@xxxxxx/
> 
> Having ^^ revert as part of the this series makes more sense. I'll
> just replace my patch with ^^ in the next re-spin.
> 

That makes sense to me.

Thanks,
Mani

> > 
> > Thanks,
> > Mani
> > 
> > > ---
> > >   drivers/remoteproc/qcom_q6v5_mss.c | 38 +++++-------------------------
> > >   1 file changed, 6 insertions(+), 32 deletions(-)
> > > 
> > > diff --git a/drivers/remoteproc/qcom_q6v5_mss.c b/drivers/remoteproc/qcom_q6v5_mss.c
> > > index 2f4027664a0e..e2f765f87ec9 100644
> > > --- a/drivers/remoteproc/qcom_q6v5_mss.c
> > > +++ b/drivers/remoteproc/qcom_q6v5_mss.c
> > > @@ -10,7 +10,6 @@
> > >   #include <linux/clk.h>
> > >   #include <linux/delay.h>
> > >   #include <linux/devcoredump.h>
> > > -#include <linux/dma-map-ops.h>
> > >   #include <linux/dma-mapping.h>
> > >   #include <linux/interrupt.h>
> > >   #include <linux/kernel.h>
> > > @@ -961,52 +960,27 @@ static void q6v5proc_halt_axi_port(struct q6v5 *qproc,
> > >   static int q6v5_mpss_init_image(struct q6v5 *qproc, const struct firmware *fw,
> > >   				const char *fw_name)
> > >   {
> > > -	unsigned long dma_attrs = DMA_ATTR_FORCE_CONTIGUOUS | DMA_ATTR_NO_KERNEL_MAPPING;
> > > -	unsigned long flags = VM_DMA_COHERENT | VM_FLUSH_RESET_PERMS;
> > > -	struct page **pages;
> > > -	struct page *page;
> > > +	unsigned long dma_attrs = DMA_ATTR_FORCE_CONTIGUOUS;
> > >   	dma_addr_t phys;
> > >   	void *metadata;
> > >   	int mdata_perm;
> > >   	int xferop_ret;
> > >   	size_t size;
> > > -	void *vaddr;
> > > -	int count;
> > > +	void *ptr;
> > >   	int ret;
> > > -	int i;
> > >   	metadata = qcom_mdt_read_metadata(fw, &size, fw_name, qproc->dev);
> > >   	if (IS_ERR(metadata))
> > >   		return PTR_ERR(metadata);
> > > -	page = dma_alloc_attrs(qproc->dev, size, &phys, GFP_KERNEL, dma_attrs);
> > > -	if (!page) {
> > > +	ptr = dma_alloc_attrs(qproc->dev, size, &phys, GFP_KERNEL, dma_attrs);
> > > +	if (!ptr) {
> > >   		kfree(metadata);
> > >   		dev_err(qproc->dev, "failed to allocate mdt buffer\n");
> > >   		return -ENOMEM;
> > >   	}
> > > -	count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> > > -	pages = kmalloc_array(count, sizeof(struct page *), GFP_KERNEL);
> > > -	if (!pages) {
> > > -		ret = -ENOMEM;
> > > -		goto free_dma_attrs;
> > > -	}
> > > -
> > > -	for (i = 0; i < count; i++)
> > > -		pages[i] = nth_page(page, i);
> > > -
> > > -	vaddr = vmap(pages, count, flags, pgprot_dmacoherent(PAGE_KERNEL));
> > > -	kfree(pages);
> > > -	if (!vaddr) {
> > > -		dev_err(qproc->dev, "unable to map memory region: %pa+%zx\n", &phys, size);
> > > -		ret = -EBUSY;
> > > -		goto free_dma_attrs;
> > > -	}
> > > -
> > > -	memcpy(vaddr, metadata, size);
> > > -
> > > -	vunmap(vaddr);
> > > +	memcpy(ptr, metadata, size);
> > >   	/* Hypervisor mapping to access metadata by modem */
> > >   	mdata_perm = BIT(QCOM_SCM_VMID_HLOS);
> > > @@ -1036,7 +1010,7 @@ static int q6v5_mpss_init_image(struct q6v5 *qproc, const struct firmware *fw,
> > >   			 "mdt buffer not reclaimed system may become unstable\n");
> > >   free_dma_attrs:
> > > -	dma_free_attrs(qproc->dev, size, page, phys, dma_attrs);
> > > +	dma_free_attrs(qproc->dev, size, ptr, phys, dma_attrs);
> > >   	kfree(metadata);
> > >   	return ret < 0 ? ret : 0;
> > > -- 
> > > 2.17.1
> > > 
> > 

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