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authorRussell King <rmk@dyn-67.arm.linux.org.uk>2005-11-25 10:52:51 -0500
committerRussell King <rmk+kernel@arm.linux.org.uk>2005-11-25 10:52:51 -0500
commit5edf71ae129167ac276ebac18b25ccc7bec6ac3e (patch)
tree619daac39d08dbf66fb19698205b263e21bba3d0
parent3c0bdac3875505516eda1c6b6e68dd84eff3b231 (diff)
[ARM] Do not call flush_tlb_kernel_range() with IRQs disabled.
We must not call TLB maintainence operations with interrupts disabled, otherwise we risk a lockup in the SMP IPI code. This means that consistent_free() can not be called from a context with IRQs disabled. In addition, we must not hold the lock in consistent_free when we call flush_tlb_kernel_range(). However, we must continue to prevent consistent_alloc() from re-using the memory region until we've finished tearing down the mapping and dealing with the TLB. Therefore, leave the vm_region entry in the list, but mark it inactive before dropping the lock and starting the tear-down process. After the mapping has been torn down, re-acquire the lock and remove the entry from the list. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--arch/arm/mm/consistent.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/arch/arm/mm/consistent.c b/arch/arm/mm/consistent.c
index 47b0b767f080..dbfe9e891f01 100644
--- a/arch/arm/mm/consistent.c
+++ b/arch/arm/mm/consistent.c
@@ -66,6 +66,7 @@ struct vm_region {
66 unsigned long vm_start; 66 unsigned long vm_start;
67 unsigned long vm_end; 67 unsigned long vm_end;
68 struct page *vm_pages; 68 struct page *vm_pages;
69 int vm_active;
69}; 70};
70 71
71static struct vm_region consistent_head = { 72static struct vm_region consistent_head = {
@@ -104,6 +105,7 @@ vm_region_alloc(struct vm_region *head, size_t size, gfp_t gfp)
104 list_add_tail(&new->vm_list, &c->vm_list); 105 list_add_tail(&new->vm_list, &c->vm_list);
105 new->vm_start = addr; 106 new->vm_start = addr;
106 new->vm_end = addr + size; 107 new->vm_end = addr + size;
108 new->vm_active = 1;
107 109
108 spin_unlock_irqrestore(&consistent_lock, flags); 110 spin_unlock_irqrestore(&consistent_lock, flags);
109 return new; 111 return new;
@@ -120,7 +122,7 @@ static struct vm_region *vm_region_find(struct vm_region *head, unsigned long ad
120 struct vm_region *c; 122 struct vm_region *c;
121 123
122 list_for_each_entry(c, &head->vm_list, vm_list) { 124 list_for_each_entry(c, &head->vm_list, vm_list) {
123 if (c->vm_start == addr) 125 if (c->vm_active && c->vm_start == addr)
124 goto out; 126 goto out;
125 } 127 }
126 c = NULL; 128 c = NULL;
@@ -319,6 +321,7 @@ EXPORT_SYMBOL(dma_mmap_writecombine);
319 321
320/* 322/*
321 * free a page as defined by the above mapping. 323 * free a page as defined by the above mapping.
324 * Must not be called with IRQs disabled.
322 */ 325 */
323void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle) 326void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle)
324{ 327{
@@ -326,14 +329,18 @@ void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr
326 unsigned long flags, addr; 329 unsigned long flags, addr;
327 pte_t *ptep; 330 pte_t *ptep;
328 331
332 WARN_ON(irqs_disabled());
333
329 size = PAGE_ALIGN(size); 334 size = PAGE_ALIGN(size);
330 335
331 spin_lock_irqsave(&consistent_lock, flags); 336 spin_lock_irqsave(&consistent_lock, flags);
332
333 c = vm_region_find(&consistent_head, (unsigned long)cpu_addr); 337 c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
334 if (!c) 338 if (!c)
335 goto no_area; 339 goto no_area;
336 340
341 c->vm_active = 0;
342 spin_unlock_irqrestore(&consistent_lock, flags);
343
337 if ((c->vm_end - c->vm_start) != size) { 344 if ((c->vm_end - c->vm_start) != size) {
338 printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n", 345 printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
339 __func__, c->vm_end - c->vm_start, size); 346 __func__, c->vm_end - c->vm_start, size);
@@ -372,8 +379,8 @@ void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr
372 379
373 flush_tlb_kernel_range(c->vm_start, c->vm_end); 380 flush_tlb_kernel_range(c->vm_start, c->vm_end);
374 381
382 spin_lock_irqsave(&consistent_lock, flags);
375 list_del(&c->vm_list); 383 list_del(&c->vm_list);
376
377 spin_unlock_irqrestore(&consistent_lock, flags); 384 spin_unlock_irqrestore(&consistent_lock, flags);
378 385
379 kfree(c); 386 kfree(c);