[PATCH 2/3] PCI: endpoint: improve pci_epf_alloc_space()

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pci_epf_alloc_space() already performs checks on the requested BAR size,
and will allocate and set epf_bar->size to a size higher than the
requested BAR size if some constraint deems it necessary.

However, other than pci_epf_alloc_space() performing these roundups,
there are checks and roundups in two different places in pci-epf-test.c.

And further checks are proposed to other endpoint function drivers, see:
https://lore.kernel.org/linux-pci/20240108151015.2030469-1-Frank.Li@xxxxxxx/

Having these checks spread out at different places in the EPF driver
(and potentially in multiple EPF drivers) is not maintainable and makes
the code hard to follow.

Since pci_epf_alloc_space() already performs roundups, move the checks and
roundups performed by pci-epf-test.c to pci_epf_alloc_space().

Signed-off-by: Niklas Cassel <cassel@xxxxxxxxxx>
---
 drivers/pci/endpoint/functions/pci-epf-test.c |  8 --------
 drivers/pci/endpoint/pci-epf-core.c           | 10 +++++++++-
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index 15bfa7d83489..981894e40681 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -841,12 +841,6 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
 	}
 	test_reg_size = test_reg_bar_size + msix_table_size + pba_size;
 
-	if (epc_features->bar_fixed_size[test_reg_bar]) {
-		if (test_reg_size > bar_size[test_reg_bar])
-			return -ENOMEM;
-		test_reg_size = bar_size[test_reg_bar];
-	}
-
 	base = pci_epf_alloc_space(epf, test_reg_size, test_reg_bar,
 				   epc_features, PRIMARY_INTERFACE);
 	if (!base) {
@@ -888,8 +882,6 @@ static void pci_epf_configure_bar(struct pci_epf *epf,
 		bar_fixed_64bit = !!(epc_features->bar_fixed_64bit & (1 << i));
 		if (bar_fixed_64bit)
 			epf_bar->flags |= PCI_BASE_ADDRESS_MEM_TYPE_64;
-		if (epc_features->bar_fixed_size[i])
-			bar_size[i] = epc_features->bar_fixed_size[i];
 	}
 }
 
diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
index e44f4078fe8b..37d9651d2026 100644
--- a/drivers/pci/endpoint/pci-epf-core.c
+++ b/drivers/pci/endpoint/pci-epf-core.c
@@ -260,6 +260,7 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
 			  const struct pci_epc_features *epc_features,
 			  enum pci_epc_interface_type type)
 {
+	u64 bar_fixed_size = epc_features->bar_fixed_size[bar];
 	size_t align = epc_features->align;
 	struct pci_epf_bar *epf_bar;
 	dma_addr_t phys_addr;
@@ -270,7 +271,14 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
 	if (size < 128)
 		size = 128;
 
-	if (align)
+	if (bar_fixed_size && size > bar_fixed_size) {
+		dev_err(dev, "requested BAR size is larger than fixed size\n");
+		return NULL;
+	}
+
+	if (bar_fixed_size)
+		size = bar_fixed_size;
+	else if (align)
 		size = ALIGN(size, align);
 	else
 		size = roundup_pow_of_two(size);
-- 
2.43.0





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