This is a note to let you know that I've just added the patch titled
s390/ism: Properly fix receive message buffer allocation
to the 6.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
s390-ism-properly-fix-receive-message-buffer-allocat.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit df972fb3bc8566aa13addad84de8495a755aacbd
Author: Gerd Bayer <gbayer@xxxxxxxxxxxxx>
Date: Mon Apr 15 15:15:07 2024 +0200
s390/ism: Properly fix receive message buffer allocation
[ Upstream commit 83781384a96b95e2b6403d3c8a002b2c89031770 ]
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 folio_alloc and
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 folio_put 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")
Signed-off-by: Gerd Bayer <gbayer@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/s390/net/ism_drv.c b/drivers/s390/net/ism_drv.c
index 2c8e964425dc3..43778b088ffac 100644
--- a/drivers/s390/net/ism_drv.c
+++ b/drivers/s390/net/ism_drv.c
@@ -292,13 +292,16 @@ 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);
+ folio_put(virt_to_folio(dmb->cpu_addr));
}
static int ism_alloc_dmb(struct ism_dev *ism, struct ism_dmb *dmb)
{
+ struct folio *folio;
unsigned long bit;
+ int rc;
if (PAGE_ALIGN(dmb->dmb_len) > dma_get_max_seg_size(&ism->pdev->dev))
return -EINVAL;
@@ -315,14 +318,30 @@ 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);
+ folio = folio_alloc(GFP_KERNEL | __GFP_NOWARN | __GFP_NOMEMALLOC |
+ __GFP_NORETRY, get_order(dmb->dmb_len));
- return dmb->cpu_addr ? 0 : -ENOMEM;
+ if (!folio) {
+ rc = -ENOMEM;
+ goto out_bit;
+ }
+
+ dmb->cpu_addr = folio_address(folio);
+ 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;
+
+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,
