On Tue, Mar 19, 2024 at 01:01:03PM -0400, Frank Li wrote: > On Tue, Mar 19, 2024 at 09:58:29PM +0530, Manivannan Sadhasivam wrote: > > On Tue, Mar 19, 2024 at 11:50:50AM -0400, Frank Li wrote: > > > On Sun, Mar 17, 2024 at 11:39:17AM +0530, Manivannan Sadhasivam wrote: > > > > As proposed during the last year 'PCI Endpoint Subsystem Open Items > > > > Discussion' of Linux Plumbers conference [1], let's migrate to Genalloc > > > > framework for managing the endpoint outbound window memory allocation. > > > > > > > > PCI Endpoint subsystem is using a custom memory allocator in pci-epc-mem > > > > driver from the start for managing the memory required to map the host > > > > address space (outbound) in endpoint. Even though it works well, it > > > > completely defeats the purpose of the 'Genalloc framework', a general > > > > purpose memory allocator framework created to avoid various custom memory > > > > allocators in the kernel. > > > > > > > > The migration to Genalloc framework is done is such a way that the existing > > > > API semantics are preserved. So that the callers of the EPC mem APIs do not > > > > need any modification (apart from the pcie-designware-epc driver that > > > > queries page size). > > > > > > > > Internally, the EPC mem driver now uses Genalloc framework's > > > > 'gen_pool_first_fit_order_align' algorithm that aligns the allocated memory > > > > based on the requested size as like the previous allocator. And the > > > > page size passed during pci_epc_mem_init() API is used as the minimum order > > > > for the memory allocations. > > > > > > > > During the migration, 'struct pci_epc_mem' is removed as it is seems > > > > redundant and the existing 'struct pci_epc_mem_window' in 'struct pci_epc' > > > > is now used to hold the address windows of the endpoint controller. > > > > > > > > [1] https://lpc.events/event/17/contributions/1419/ > > > > > > > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > > > > --- > > > > drivers/pci/controller/dwc/pcie-designware-ep.c | 14 +- > > > > drivers/pci/endpoint/pci-epc-mem.c | 182 +++++++++--------------- > > > > include/linux/pci-epc.h | 25 +--- > > > > 3 files changed, 81 insertions(+), 140 deletions(-) > > > > > > > > diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c > > > > index 5befed2dc02b..37c612282eb6 100644 > > > > --- a/drivers/pci/controller/dwc/pcie-designware-ep.c > > > > +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c > > > > @@ -482,11 +482,11 @@ int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 func_no, > > > > reg = ep_func->msi_cap + PCI_MSI_DATA_32; > > > > msg_data = dw_pcie_ep_readw_dbi(ep, func_no, reg); > > > > } > > > > - aligned_offset = msg_addr_lower & (epc->mem->window.page_size - 1); > > > > + aligned_offset = msg_addr_lower & (epc->windows[0]->page_size - 1); > > > > msg_addr = ((u64)msg_addr_upper) << 32 | > > > > (msg_addr_lower & ~aligned_offset); > > > > ret = dw_pcie_ep_map_addr(epc, func_no, 0, ep->msi_mem_phys, msg_addr, > > > > - epc->mem->window.page_size); > > > > + epc->windows[0]->page_size); > > > > if (ret) > > > > return ret; > > > > > > > > @@ -550,10 +550,10 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no, > > > > return -EPERM; > > > > } > > > > > > > > - aligned_offset = msg_addr & (epc->mem->window.page_size - 1); > > > > + aligned_offset = msg_addr & (epc->windows[0]->page_size - 1); > > > > msg_addr &= ~aligned_offset; > > > > ret = dw_pcie_ep_map_addr(epc, func_no, 0, ep->msi_mem_phys, msg_addr, > > > > - epc->mem->window.page_size); > > > > + epc->windows[0]->page_size); > > > > if (ret) > > > > return ret; > > > > > > > > @@ -572,7 +572,7 @@ void dw_pcie_ep_exit(struct dw_pcie_ep *ep) > > > > dw_pcie_edma_remove(pci); > > > > > > > > pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem, > > > > - epc->mem->window.page_size); > > > > + epc->windows[0]->page_size); > > > > > > > > pci_epc_mem_exit(epc); > > > > > > > > @@ -742,7 +742,7 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep) > > > > } > > > > > > > > ep->msi_mem = pci_epc_mem_alloc_addr(epc, &ep->msi_mem_phys, > > > > - epc->mem->window.page_size); > > > > + epc->windows[0]->page_size); > > > > if (!ep->msi_mem) { > > > > ret = -ENOMEM; > > > > dev_err(dev, "Failed to reserve memory for MSI/MSI-X\n"); > > > > @@ -770,7 +770,7 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep) > > > > > > > > err_free_epc_mem: > > > > pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem, > > > > - epc->mem->window.page_size); > > > > + epc->windows[0]->page_size); > > > > > > > > err_exit_epc_mem: > > > > pci_epc_mem_exit(epc); > > > > diff --git a/drivers/pci/endpoint/pci-epc-mem.c b/drivers/pci/endpoint/pci-epc-mem.c > > > > index a9c028f58da1..f9e6e1a6aeaa 100644 > > > > --- a/drivers/pci/endpoint/pci-epc-mem.c > > > > +++ b/drivers/pci/endpoint/pci-epc-mem.c > > > > @@ -4,37 +4,18 @@ > > > > * > > > > * Copyright (C) 2017 Texas Instruments > > > > * Author: Kishon Vijay Abraham I <kishon@xxxxxx> > > > > + * > > > > + * Copyright (C) 2024 Linaro Ltd. > > > > + * Author: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > > > > */ > > > > > > > > +#include <linux/genalloc.h> > > > > #include <linux/io.h> > > > > #include <linux/module.h> > > > > #include <linux/slab.h> > > > > > > > > #include <linux/pci-epc.h> > > > > > > > > -/** > > > > - * pci_epc_mem_get_order() - determine the allocation order of a memory size > > > > - * @mem: address space of the endpoint controller > > > > - * @size: the size for which to get the order > > > > - * > > > > - * Reimplement get_order() for mem->page_size since the generic get_order > > > > - * always gets order with a constant PAGE_SIZE. > > > > - */ > > > > -static int pci_epc_mem_get_order(struct pci_epc_mem *mem, size_t size) > > > > -{ > > > > - int order; > > > > - unsigned int page_shift = ilog2(mem->window.page_size); > > > > - > > > > - size--; > > > > - size >>= page_shift; > > > > -#if BITS_PER_LONG == 32 > > > > - order = fls(size); > > > > -#else > > > > - order = fls64(size); > > > > -#endif > > > > - return order; > > > > -} > > > > - > > > > /** > > > > * pci_epc_multi_mem_init() - initialize the pci_epc_mem structure > > > > * @epc: the EPC device that invoked pci_epc_mem_init > > > > @@ -48,17 +29,11 @@ int pci_epc_multi_mem_init(struct pci_epc *epc, > > > > struct pci_epc_mem_window *windows, > > > > unsigned int num_windows) > > > > { > > > > - struct pci_epc_mem *mem = NULL; > > > > - unsigned long *bitmap = NULL; > > > > - unsigned int page_shift; > > > > + struct pci_epc_mem_window *window = NULL; > > > > size_t page_size; > > > > - int bitmap_size; > > > > - int pages; > > > > int ret; > > > > int i; > > > > > > > > - epc->num_windows = 0; > > > > - > > > > if (!windows || !num_windows) > > > > return -EINVAL; > > > > > > > > @@ -70,45 +45,51 @@ int pci_epc_multi_mem_init(struct pci_epc *epc, > > > > page_size = windows[i].page_size; > > > > if (page_size < PAGE_SIZE) > > > > page_size = PAGE_SIZE; > > > > - page_shift = ilog2(page_size); > > > > - pages = windows[i].size >> page_shift; > > > > - bitmap_size = BITS_TO_LONGS(pages) * sizeof(long); > > > > > > > > - mem = kzalloc(sizeof(*mem), GFP_KERNEL); > > > > - if (!mem) { > > > > + windows[i].pool = gen_pool_create(ilog2(page_size), -1); > > > > > > I think it is not good to modify caller's memory. This funciton suppose > > > pass down read-only information. And set to epc->windows[i]. I think it'd > > > better to use epc->windows[i].pool/windows. > > > > > > > What do you mean by modifying caller's memory? Here, the memory for epc->windows > > is being allocated and the pool is created for each window. > > windows[i].pool = gen_pool_create(ilog2(page_size), -1) > > 'windows' pass down from argument pci_epc_multi_mem_init( > ..struct pci_epc_mem_window *windows, ) > ^^^^^^^ > windows[i].pool = gen_pool_create() actually change the caller's stack > memory. > Hmm, you are right. Will fix it. > > > > > > + if (!windows[i].pool) { > > > > ret = -ENOMEM; > > > > - i--; > > > > - goto err_mem; > > > > + goto err_free_mem; > > > > + } > > > > + > > > > + gen_pool_set_algo(windows[i].pool, gen_pool_first_fit_order_align, > > > > + NULL); > > > > + > > > > + windows[i].virt_base = ioremap(windows[i].phys_base, windows[i].size); > > > > + ret = gen_pool_add_virt(windows[i].pool, (unsigned long)windows[i].virt_base, > > > > + windows[i].phys_base, windows[i].size, -1); > > > > + if (ret) { > > > > + iounmap(windows[i].virt_base); > > > > + gen_pool_destroy(epc->windows[i]->pool); > > > > > > I think move all free to err path will be easy to understand. > > > > > > > It is not straightforward. First we need to free the memory for current > > iteration and then all previous iterations, that too from different places. > > Moving the code to free current iteration to the error label will look messy. > > All from current iteration. > > err_free_mem: > iounmap(windows[i].virt_base); > if (epc->windows[i]->pool) > gen_pool_destroy(epc->windows[i]->pool) Initially I thought it would look messy if the memory for current iteration is freed in the error labels. But now I implemented it and it doesn't look that bad. So will change it in next iteration. > > > > > > > + goto err_free_mem; > > > > } > > > > > > > > - bitmap = kzalloc(bitmap_size, GFP_KERNEL); > > > > - if (!bitmap) { > > > > + window = kzalloc(sizeof(*window), GFP_KERNEL); > > > > > > According to below code > > > > > > epc->windows = kcalloc(num_windows, sizeof(*epc->windows), GFP_KERNEL); > > > if (!epc->windows) > > > return -ENOMEM; > > > > > > epc->windows already allocate whole num_windows * "struct pci_epc_mem_window". > > > I think you can direct use 'window = epc->windows + i', so needn't alloc > > > additional memory for epc->windows[i]. > > > > > > > First we are allocating the memory for 'struct pci_epc_mem_window' _pointers_ in > > epc->windows. Then we need to allocate memory for each pointer in epc->windows > > to actually store data. Otherwise, we will be referencing the nulll pointer. > > I think two layer pointer is totally unecessary. > You can use one layer pointer 'struct pci_epc_mem_window *windows;' > How can you store multiple 'struct pci_epc_mem_window' with a single pointer? Please elaborate. - Mani -- மணிவண்ணன் சதாசிவம்
