[PATCH 02/19] PCI: endpoint: Improve pci_epc_mem_alloc_addr()

Damien Le Moal
2024-03-29T09:09:51Z

There is no point in attempting to allocate memory from an endpoint
controller memory window if the requested size is larger than the window
size. Add a check to skip bitmap_find_free_region() calls for such case.
Also change the final return to return NULL to simplify the code.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
drivers/pci/endpoint/pci-epc-mem.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/endpoint/pci-epc-mem.c b/drivers/pci/endpoint/pci-epc-mem.c
index a9c028f58da1..218a60e945db 100644
--- a/drivers/pci/endpoint/pci-epc-mem.c
+++ b/drivers/pci/endpoint/pci-epc-mem.c
@@ -178,7 +178,7 @@ EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
phys_addr_t *phys_addr, size_t size)
{
- void __iomem *virt_addr = NULL;
+ void __iomem *virt_addr;
struct pci_epc_mem *mem;
unsigned int page_shift;
size_t align_size;
@@ -188,10 +188,13 @@ void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,

for (i = 0; i < epc->num_windows; i++) {
mem = epc->windows[i];
- mutex_lock(&mem->lock);
+ if (size > mem->window.size)
+ continue;
+
align_size = ALIGN(size, mem->window.page_size);
order = pci_epc_mem_get_order(mem, align_size);

+ mutex_lock(&mem->lock);
pageno = bitmap_find_free_region(mem->bitmap, mem->pages,
order);
if (pageno >= 0) {
@@ -211,7 +214,7 @@ void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
mutex_unlock(&mem->lock);
}

- return virt_addr;
+ return NULL;
}
EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);

--
2.44.0