6.12-stable review patch. If anyone has any objections, please let me know.
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From: Jerome Brunet jbrunet@baylibre.com
[ Upstream commit 793908d60b8745c386b9f4e29eb702f74ceb0886 ]
When allocating space for an endpoint function on a BAR with a fixed size, the size saved in 'struct pci_epf_bar.size' should be the fixed size as expected by pci_epc_set_bar().
However, if pci_epf_alloc_space() increased the allocation size to accommodate iATU alignment requirements, it previously saved the larger aligned size in .size, which broke pci_epc_set_bar().
To solve this, keep the fixed BAR size in .size and save the aligned size in a new .aligned_size for use when deallocating it.
Fixes: 2a9a801620ef ("PCI: endpoint: Add support to specify alignment for buffers allocated to BARs") Signed-off-by: Jerome Brunet jbrunet@baylibre.com [mani: commit message fixup] Signed-off-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org [bhelgaas: more specific subject, commit log, wrap comment to match file] Signed-off-by: Bjorn Helgaas bhelgaas@google.com Reviewed-by: Niklas Cassel cassel@kernel.org Link: https://patch.msgid.link/20250424-pci-ep-size-alignment-v5-1-2d4ec2af23f5@ba... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/endpoint/pci-epf-core.c | 22 +++++++++++++++------- include/linux/pci-epf.h | 3 +++ 2 files changed, 18 insertions(+), 7 deletions(-)
diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c index 50bc2892a36c5..963d2f3aa5d47 100644 --- a/drivers/pci/endpoint/pci-epf-core.c +++ b/drivers/pci/endpoint/pci-epf-core.c @@ -236,12 +236,13 @@ void pci_epf_free_space(struct pci_epf *epf, void *addr, enum pci_barno bar, }
dev = epc->dev.parent; - dma_free_coherent(dev, epf_bar[bar].size, addr, + dma_free_coherent(dev, epf_bar[bar].aligned_size, addr, epf_bar[bar].phys_addr);
epf_bar[bar].phys_addr = 0; epf_bar[bar].addr = NULL; epf_bar[bar].size = 0; + epf_bar[bar].aligned_size = 0; epf_bar[bar].barno = 0; epf_bar[bar].flags = 0; } @@ -264,7 +265,7 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar, enum pci_epc_interface_type type) { u64 bar_fixed_size = epc_features->bar[bar].fixed_size; - size_t align = epc_features->align; + size_t aligned_size, align = epc_features->align; struct pci_epf_bar *epf_bar; dma_addr_t phys_addr; struct pci_epc *epc; @@ -281,12 +282,18 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar, return NULL; } size = bar_fixed_size; + } else { + /* BAR size must be power of two */ + size = roundup_pow_of_two(size); }
- if (align) - size = ALIGN(size, align); - else - size = roundup_pow_of_two(size); + /* + * Allocate enough memory to accommodate the iATU alignment + * requirement. In most cases, this will be the same as .size but + * it might be different if, for example, the fixed size of a BAR + * is smaller than align. + */ + aligned_size = align ? ALIGN(size, align) : size;
if (type == PRIMARY_INTERFACE) { epc = epf->epc; @@ -297,7 +304,7 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar, }
dev = epc->dev.parent; - space = dma_alloc_coherent(dev, size, &phys_addr, GFP_KERNEL); + space = dma_alloc_coherent(dev, aligned_size, &phys_addr, GFP_KERNEL); if (!space) { dev_err(dev, "failed to allocate mem space\n"); return NULL; @@ -306,6 +313,7 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar, epf_bar[bar].phys_addr = phys_addr; epf_bar[bar].addr = space; epf_bar[bar].size = size; + epf_bar[bar].aligned_size = aligned_size; epf_bar[bar].barno = bar; if (upper_32_bits(size) || epc_features->bar[bar].only_64bit) epf_bar[bar].flags |= PCI_BASE_ADDRESS_MEM_TYPE_64; diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h index 18a3aeb62ae4e..cd6f8f4bc4540 100644 --- a/include/linux/pci-epf.h +++ b/include/linux/pci-epf.h @@ -114,6 +114,8 @@ struct pci_epf_driver { * @phys_addr: physical address that should be mapped to the BAR * @addr: virtual address corresponding to the @phys_addr * @size: the size of the address space present in BAR + * @aligned_size: the size actually allocated to accommodate the iATU alignment + * requirement * @barno: BAR number * @flags: flags that are set for the BAR */ @@ -121,6 +123,7 @@ struct pci_epf_bar { dma_addr_t phys_addr; void *addr; size_t size; + size_t aligned_size; enum pci_barno barno; int flags; };