Re: [Xenomai-core] Comedi buffer management.
Alexis Berlemont wrote: > Hi Gilles, > > Sorry for answering so late. I was unable to regularly check my private mails > the last week; I missed yours. > >> I commited in trunk a fix of Xenomai heap management for the highmem >> case. What the patch does is essentially replacing __va_to_kva (which >> does not work correctly with highmem) with vmalloc_to_page, which is >> available on all linux versions Xenomai supports. >> >> However, I found that comedi buffer management also uses __va_to_kva. We >> can fix SetPageReserved and ClearPageReserved easily to use >> vmalloc_to_page, however, I do not see what pg_list is used for, so do >> not really know how to fix it. Here is a proposed patch: > > If I remember well, pg_list may be used by some PCI/PCIe DMA components which > can dump acquired data to physically non-contiguous buffers. In such cases, > the driver has to provide a list of the pages addresses into which the DMA > controller can trigger shots. > > Many thanks for your fix. No problem, really, I actually did not fix pg_list. It will not work with highmem. What do the DMA needs? physical adresses? Then you need to replace page_address(vmalloc_to_page(vaddr)) with page_to_phys(vmalloc_to_page(vaddr)) Or you may store the struct page, and let the drivers do what they want with it. -- Gilles. ___ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
Re: [Xenomai-core] Comedi buffer management.
Hi Gilles, Sorry for answering so late. I was unable to regularly check my private mails the last week; I missed yours. > I commited in trunk a fix of Xenomai heap management for the highmem > case. What the patch does is essentially replacing __va_to_kva (which > does not work correctly with highmem) with vmalloc_to_page, which is > available on all linux versions Xenomai supports. > > However, I found that comedi buffer management also uses __va_to_kva. We > can fix SetPageReserved and ClearPageReserved easily to use > vmalloc_to_page, however, I do not see what pg_list is used for, so do > not really know how to fix it. Here is a proposed patch: If I remember well, pg_list may be used by some PCI/PCIe DMA components which can dump acquired data to physically non-contiguous buffers. In such cases, the driver has to provide a list of the pages addresses into which the DMA controller can trigger shots. Many thanks for your fix. Alexis. > Index: ksrc/drivers/comedi/buffer.c > === > --- ksrc/drivers/comedi/buffer.c (revision 4211) > +++ ksrc/drivers/comedi/buffer.c (working copy) > @@ -46,7 +46,7 @@ void comedi_free_buffer(comedi_buf_t * b > unsigned long vaddr, vabase = (unsigned long)buf_desc->buf; > for (vaddr = vabase; vaddr < vabase + buf_desc->size; >vaddr += PAGE_SIZE) > - ClearPageReserved(virt_to_page(__va_to_kva(vaddr))); > + ClearPageReserved(vmalloc_to_page(vaddr)); > vfree(buf_desc->buf); > buf_desc->buf = NULL; > } > @@ -73,7 +73,7 @@ int comedi_alloc_buffer(comedi_buf_t * b > > for (vaddr = vabase; vaddr < vabase + buf_desc->size; >vaddr += PAGE_SIZE) > - SetPageReserved(virt_to_page(__va_to_kva(vaddr))); > + SetPageReserved(vmalloc_to_page(vaddr)); > > buf_desc->pg_list = comedi_kmalloc(((buf_desc->size) >> PAGE_SHIFT) * > sizeof(unsigned long)); > @@ -85,7 +85,7 @@ int comedi_alloc_buffer(comedi_buf_t * b > for (vaddr = vabase; vaddr < vabase + buf_desc->size; >vaddr += PAGE_SIZE) > buf_desc->pg_list[(vaddr - vabase) >> PAGE_SHIFT] = > - __va_to_kva(vaddr); > + (unsigned long) vmalloc_to_page(vaddr); > >out_virt_contig_alloc: > if (ret != 0) > > Cheers. ___ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
Re: [Xenomai-core] Comedi buffer management.
Gilles Chanteperdrix wrote: > Hi Alex, > > I commited in trunk a fix of Xenomai heap management for the highmem > case. What the patch does is essentially replacing __va_to_kva (which > does not work correctly with highmem) with vmalloc_to_page, which is > available on all linux versions Xenomai supports. > > However, I found that comedi buffer management also uses __va_to_kva. We > can fix SetPageReserved and ClearPageReserved easily to use > vmalloc_to_page, however, I do not see what pg_list is used for, so do > not really know how to fix it. Here is a proposed patch: > > Index: ksrc/drivers/comedi/buffer.c > === > --- ksrc/drivers/comedi/buffer.c (revision 4211) > +++ ksrc/drivers/comedi/buffer.c (working copy) > @@ -46,7 +46,7 @@ void comedi_free_buffer(comedi_buf_t * b > unsigned long vaddr, vabase = (unsigned long)buf_desc->buf; > for (vaddr = vabase; vaddr < vabase + buf_desc->size; >vaddr += PAGE_SIZE) > - ClearPageReserved(virt_to_page(__va_to_kva(vaddr))); > + ClearPageReserved(vmalloc_to_page(vaddr)); > vfree(buf_desc->buf); > buf_desc->buf = NULL; > } > @@ -73,7 +73,7 @@ int comedi_alloc_buffer(comedi_buf_t * b > > for (vaddr = vabase; vaddr < vabase + buf_desc->size; >vaddr += PAGE_SIZE) > - SetPageReserved(virt_to_page(__va_to_kva(vaddr))); > + SetPageReserved(vmalloc_to_page(vaddr)); > > buf_desc->pg_list = comedi_kmalloc(((buf_desc->size) >> PAGE_SHIFT) * > sizeof(unsigned long)); > @@ -85,7 +85,7 @@ int comedi_alloc_buffer(comedi_buf_t * b > for (vaddr = vabase; vaddr < vabase + buf_desc->size; >vaddr += PAGE_SIZE) > buf_desc->pg_list[(vaddr - vabase) >> PAGE_SHIFT] = > - __va_to_kva(vaddr); > + (unsigned long) vmalloc_to_page(vaddr); Ok. Due to my change the trunk was no longer compiling with comedi enabled, so I commited a temporary change: instead of storing __va_to_kva(vaddr) into the pg_list array, I store page_address(vmalloc_to_page(vaddr)), which should have the same value. But is incorrect with highmem. -- Gilles. ___ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
