On Thu, 2024-03-28 at 16:41 +0100, Gerd Bayer wrote: > Since [1], dma_alloc_coherent() does not accept requests for GFP_COMP > anymore, even on archs that may be able to fulfill this. > Functionality that > relied on the receive buffer being a compound page broke at that > point: > The SMC-D protocol, that utilizes the ism device driver, passes > receive > buffers to the splice processor in a struct splice_pipe_desc with a > single entry list of struct pages. As the buffer is no longer a > compound > page, the splice processor now rejects requests to handle more than a > page worth of data. > > Replace dma_alloc_coherent() and allocate a buffer with kmalloc() > then > create a DMA map for it with dma_map_page(). Since only receive > buffers > on ISM devices use DMA, qualify the mapping as FROM_DEVICE. > Since ISM devices are available on arch s390, only and on that arch > all > DMA is coherent, there is no need to introduce and export some kind > of > dma_sync_to_cpu() method to be called by the SMC-D protocol layer. > > Analogously, replace dma_free_coherent by a two step dma_unmap_page, > then kfree to free the receive buffer. > > [1] https://lore.kernel.org/all/20221113163535.884299-1-hch@xxxxxx/ > > Fixes: c08004eede4b ("s390/ism: don't pass bogus GFP_ flags to > dma_alloc_coherent") Late adding Christoph as the "blamed" committer. > Signed-off-by: Gerd Bayer <gbayer@xxxxxxxxxxxxx> > --- > drivers/s390/net/ism_drv.c | 35 ++++++++++++++++++++++++++--------- > 1 file changed, 26 insertions(+), 9 deletions(-) > > diff --git a/drivers/s390/net/ism_drv.c b/drivers/s390/net/ism_drv.c > index 2c8e964425dc..25911b887e5e 100644 > --- a/drivers/s390/net/ism_drv.c > +++ b/drivers/s390/net/ism_drv.c > @@ -14,6 +14,8 @@ > #include <linux/err.h> > #include <linux/ctype.h> > #include <linux/processor.h> > +#include <linux/dma-direction.h> > +#include <linux/gfp_types.h> > > #include "ism.h" > > @@ -292,13 +294,15 @@ static int ism_read_local_gid(struct ism_dev > *ism) > static void ism_free_dmb(struct ism_dev *ism, struct ism_dmb *dmb) > { > clear_bit(dmb->sba_idx, ism->sba_bitmap); > - dma_free_coherent(&ism->pdev->dev, dmb->dmb_len, > - dmb->cpu_addr, dmb->dma_addr); > + dma_unmap_page(&ism->pdev->dev, dmb->dma_addr, dmb->dmb_len, > + DMA_FROM_DEVICE); > + kfree(dmb->cpu_addr); > } > > static int ism_alloc_dmb(struct ism_dev *ism, struct ism_dmb *dmb) > { > unsigned long bit; > + int rc; > > if (PAGE_ALIGN(dmb->dmb_len) > dma_get_max_seg_size(&ism- > >pdev->dev)) > return -EINVAL; > @@ -315,14 +319,27 @@ static int ism_alloc_dmb(struct ism_dev *ism, > struct ism_dmb *dmb) > test_and_set_bit(dmb->sba_idx, ism->sba_bitmap)) > return -EINVAL; > > - dmb->cpu_addr = dma_alloc_coherent(&ism->pdev->dev, dmb- > >dmb_len, > - &dmb->dma_addr, > - GFP_KERNEL | __GFP_NOWARN > | > - __GFP_NOMEMALLOC | > __GFP_NORETRY); > - if (!dmb->cpu_addr) > - clear_bit(dmb->sba_idx, ism->sba_bitmap); > + dmb->cpu_addr = kmalloc(dmb->dmb_len, GFP_KERNEL | > __GFP_NOWARN | > + __GFP_COMP | __GFP_NOMEMALLOC | > __GFP_NORETRY); > + if (!dmb->cpu_addr) { > + rc = -ENOMEM; > + goto out_bit; > + } > + dmb->dma_addr = dma_map_page(&ism->pdev->dev, > + virt_to_page(dmb->cpu_addr), 0, > + dmb->dmb_len, DMA_FROM_DEVICE); > + if (dma_mapping_error(&ism->pdev->dev, dmb->dma_addr)) { > + rc = -ENOMEM; > + goto out_free; > + } > + > + return 0; > > - return dmb->cpu_addr ? 0 : -ENOMEM; > +out_free: > + kfree(dmb->cpu_addr); > +out_bit: > + clear_bit(dmb->sba_idx, ism->sba_bitmap); > + return rc; > } > > int ism_register_dmb(struct ism_dev *ism, struct ism_dmb *dmb,
