PCI: endpoint: Fix for concurrent memory allocation in OB address region

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.

Kishon Vijay Abraham I committed 6 years ago

Commit 04e046c1 parent 3d3248d2 files · +11 −2Browse files

Unified · Split

2 files

drivers/pci/endpoint/pci-epc-mem.c +8 −2
include/linux/pci-epc.h +3 −0

drivers/pci/endpoint/pci-epc-mem.c+8−2

@@ -79,6 +79,7 @@ int __pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_base, size_t size, · 78 unmodified lines
79	79	mem->page_size = page_size;
80	80	mem->pages = pages;
81	81	mem->size = size;
	82	+ mutex_init(&mem->lock);
82	83
83	84	epc->mem = mem;
84	85
@@ -122,7 +123,7 @@ void __iomem pci_epc_mem_alloc_addr(struct pci_epc epc, · 37 unmodified lines
122	123	phys_addr_t *phys_addr, size_t size)
123	124	{
124	125	int pageno;
125		− void __iomem *virt_addr;
	126	+ void __iomem *virt_addr = NULL;
126	127	struct pci_epc_mem *mem = epc->mem;
127	128	unsigned int page_shift = ilog2(mem->page_size);
128	129	int order;
@@ -130,15 +131,18 @@ void __iomem pci_epc_mem_alloc_addr(struct pci_epc epc, · 1 unmodified line
130	131	size = ALIGN(size, mem->page_size);
131	132	order = pci_epc_mem_get_order(mem, size);
132	133
	134	+ mutex_lock(&mem->lock);
133	135	pageno = bitmap_find_free_region(mem->bitmap, mem->pages, order);
134	136	if (pageno < 0)
135		− return NULL;
	137	+ goto ret;
136	138
137	139	*phys_addr = mem->phys_base + ((phys_addr_t)pageno << page_shift);
138	140	virt_addr = ioremap(*phys_addr, size);
139	141	if (!virt_addr)
140	142	bitmap_release_region(mem->bitmap, pageno, order);
141	143
	144	+ret:
	145	+ mutex_unlock(&mem->lock);
142	146	return virt_addr;
143	147	}
144	148	EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
@@ -164,7 +168,9 @@ void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr, · 19 unmodified lines
164	168	pageno = (phys_addr - mem->phys_base) >> page_shift;
165	169	size = ALIGN(size, mem->page_size);
166	170	order = pci_epc_mem_get_order(mem, size);
	171	+ mutex_lock(&mem->lock);
167	172	bitmap_release_region(mem->bitmap, pageno, order);
	173	+ mutex_unlock(&mem->lock);
168	174	}
169	175	EXPORT_SYMBOL_GPL(pci_epc_mem_free_addr);
170	176

include/linux/pci-epc.h+3−0

@@ -71,6 +71,7 @@ struct pci_epc_ops { · 70 unmodified lines
71	71	* @bitmap: bitmap to manage the PCI address space
72	72	* @pages: number of bits representing the address region
73	73	* @page_size: size of each page
	74	+ * @lock: mutex to protect bitmap
74	75	*/
75	76	struct pci_epc_mem {
76	77	phys_addr_t phys_base;
@@ -78,6 +79,8 @@ struct pci_epc_mem { · 1 unmodified line
78	79	unsigned long *bitmap;
79	80	size_t page_size;
80	81	int pages;
	82	+ /* mutex to protect against concurrent access for memory allocation*/
	83	+ struct mutex lock;
81	84	};
82	85
83	86	/**