[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>
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3c0bdac387
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@ -66,6 +66,7 @@ struct vm_region {
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unsigned long vm_start;
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unsigned long vm_start;
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unsigned long vm_end;
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unsigned long vm_end;
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struct page *vm_pages;
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struct page *vm_pages;
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int vm_active;
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};
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};
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static struct vm_region consistent_head = {
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static struct vm_region consistent_head = {
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@ -104,6 +105,7 @@ vm_region_alloc(struct vm_region *head, size_t size, gfp_t gfp)
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list_add_tail(&new->vm_list, &c->vm_list);
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list_add_tail(&new->vm_list, &c->vm_list);
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new->vm_start = addr;
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new->vm_start = addr;
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new->vm_end = addr + size;
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new->vm_end = addr + size;
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new->vm_active = 1;
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spin_unlock_irqrestore(&consistent_lock, flags);
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spin_unlock_irqrestore(&consistent_lock, flags);
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return new;
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return new;
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@ -120,7 +122,7 @@ static struct vm_region *vm_region_find(struct vm_region *head, unsigned long ad
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struct vm_region *c;
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struct vm_region *c;
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list_for_each_entry(c, &head->vm_list, vm_list) {
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list_for_each_entry(c, &head->vm_list, vm_list) {
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if (c->vm_start == addr)
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if (c->vm_active && c->vm_start == addr)
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goto out;
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goto out;
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}
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}
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c = NULL;
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c = NULL;
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@ -319,6 +321,7 @@ EXPORT_SYMBOL(dma_mmap_writecombine);
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/*
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/*
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* free a page as defined by the above mapping.
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* free a page as defined by the above mapping.
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* Must not be called with IRQs disabled.
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*/
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*/
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void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle)
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void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle)
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{
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{
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@ -326,14 +329,18 @@ void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr
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unsigned long flags, addr;
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unsigned long flags, addr;
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pte_t *ptep;
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pte_t *ptep;
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WARN_ON(irqs_disabled());
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size = PAGE_ALIGN(size);
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size = PAGE_ALIGN(size);
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spin_lock_irqsave(&consistent_lock, flags);
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spin_lock_irqsave(&consistent_lock, flags);
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c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
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c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
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if (!c)
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if (!c)
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goto no_area;
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goto no_area;
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c->vm_active = 0;
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spin_unlock_irqrestore(&consistent_lock, flags);
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if ((c->vm_end - c->vm_start) != size) {
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if ((c->vm_end - c->vm_start) != size) {
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printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
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printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
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__func__, c->vm_end - c->vm_start, size);
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__func__, c->vm_end - c->vm_start, size);
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@ -372,8 +379,8 @@ void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr
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flush_tlb_kernel_range(c->vm_start, c->vm_end);
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flush_tlb_kernel_range(c->vm_start, c->vm_end);
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spin_lock_irqsave(&consistent_lock, flags);
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list_del(&c->vm_list);
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list_del(&c->vm_list);
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spin_unlock_irqrestore(&consistent_lock, flags);
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spin_unlock_irqrestore(&consistent_lock, flags);
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kfree(c);
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kfree(c);
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