From: Kishon Vijay Abraham I kishon@ti.com
commit 04e046ca57ebed3943422dee10eec9e73aec081e upstream.
pci-epc-mem uses a bitmap to manage the Endpoint outbound (OB) address region. This address region will be shared by multiple endpoint functions (in the case of multi function endpoint) and it has to be protected from concurrent access to avoid updating an inconsistent state.
Use a mutex to protect bitmap updates to prevent the memory allocation API from returning incorrect addresses.
Signed-off-by: Kishon Vijay Abraham I kishon@ti.com Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Cc: stable@vger.kernel.org # v4.14+ Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/pci/endpoint/pci-epc-mem.c | 10 ++++++++-- include/linux/pci-epc.h | 3 +++ 2 files changed, 11 insertions(+), 2 deletions(-)
--- a/drivers/pci/endpoint/pci-epc-mem.c +++ b/drivers/pci/endpoint/pci-epc-mem.c @@ -90,6 +90,7 @@ int __pci_epc_mem_init(struct pci_epc *e mem->page_size = page_size; mem->pages = pages; mem->size = size; + mutex_init(&mem->lock);
epc->mem = mem;
@@ -133,7 +134,7 @@ void __iomem *pci_epc_mem_alloc_addr(str phys_addr_t *phys_addr, size_t size) { int pageno; - void __iomem *virt_addr; + void __iomem *virt_addr = NULL; struct pci_epc_mem *mem = epc->mem; unsigned int page_shift = ilog2(mem->page_size); int order; @@ -141,15 +142,18 @@ void __iomem *pci_epc_mem_alloc_addr(str size = ALIGN(size, mem->page_size); order = pci_epc_mem_get_order(mem, size);
+ mutex_lock(&mem->lock); pageno = bitmap_find_free_region(mem->bitmap, mem->pages, order); if (pageno < 0) - return NULL; + goto ret;
*phys_addr = mem->phys_base + (pageno << page_shift); virt_addr = ioremap(*phys_addr, size); if (!virt_addr) bitmap_release_region(mem->bitmap, pageno, order);
+ret: + mutex_unlock(&mem->lock); return virt_addr; } EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr); @@ -175,7 +179,9 @@ void pci_epc_mem_free_addr(struct pci_ep pageno = (phys_addr - mem->phys_base) >> page_shift; size = ALIGN(size, mem->page_size); order = pci_epc_mem_get_order(mem, size); + mutex_lock(&mem->lock); bitmap_release_region(mem->bitmap, pageno, order); + mutex_unlock(&mem->lock); } EXPORT_SYMBOL_GPL(pci_epc_mem_free_addr);
--- a/include/linux/pci-epc.h +++ b/include/linux/pci-epc.h @@ -63,6 +63,7 @@ struct pci_epc_ops { * @bitmap: bitmap to manage the PCI address space * @pages: number of bits representing the address region * @page_size: size of each page + * @lock: mutex to protect bitmap */ struct pci_epc_mem { phys_addr_t phys_base; @@ -70,6 +71,8 @@ struct pci_epc_mem { unsigned long *bitmap; size_t page_size; int pages; + /* mutex to protect against concurrent access for memory allocation*/ + struct mutex lock; };
/**