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[ARM] Do not call flush_tlb_kernel_range() with IRQs disabled.

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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>
This commit is contained in:
Russell King 2005-11-25 15:52:51 +00:00 committed by Russell King
parent 3c0bdac387
commit 5edf71ae12
1 changed files with 10 additions and 3 deletions
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13
arch/arm/mm/consistent.c
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@ -66,6 +66,7 @@ struct vm_region {
unsigned long vm_start;
unsigned long vm_end;
struct page *vm_pages;
int vm_active;
};
static struct vm_region consistent_head = {
@ -104,6 +105,7 @@ vm_region_alloc(struct vm_region *head, size_t size, gfp_t gfp)
list_add_tail(&new->vm_list, &c->vm_list);
new->vm_start = addr;
new->vm_end = addr + size;
new->vm_active = 1;
spin_unlock_irqrestore(&consistent_lock, flags);
return new;
@ -120,7 +122,7 @@ static struct vm_region *vm_region_find(struct vm_region *head, unsigned long ad
struct vm_region *c;
list_for_each_entry(c, &head->vm_list, vm_list) {
if (c->vm_start == addr)
if (c->vm_active && c->vm_start == addr)
goto out;
}
c = NULL;
@ -319,6 +321,7 @@ EXPORT_SYMBOL(dma_mmap_writecombine);
/*
* free a page as defined by the above mapping.
* Must not be called with IRQs disabled.
*/
void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle)
{
@ -326,14 +329,18 @@ void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr
unsigned long flags, addr;
pte_t *ptep;
WARN_ON(irqs_disabled());
size = PAGE_ALIGN(size);
spin_lock_irqsave(&consistent_lock, flags);
c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
if (!c)
goto no_area;
c->vm_active = 0;
spin_unlock_irqrestore(&consistent_lock, flags);
if ((c->vm_end - c->vm_start) != size) {
printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
__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
flush_tlb_kernel_range(c->vm_start, c->vm_end);
spin_lock_irqsave(&consistent_lock, flags);
list_del(&c->vm_list);
spin_unlock_irqrestore(&consistent_lock, flags);
kfree(c);