On Fri, Oct 04, 2024 at 02:07:37PM +0900, Damien Le Moal wrote:
> 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@xxxxxxxxxx>
> ---
> 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);
Perhaps mention in the commit message why it is safe to move the mutex_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);
>
> --
> 2.46.2
>
