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Commit 5a4e6dcc authored by Roland Dreier's avatar Roland Dreier
Browse files

IB/mthca: Use IRQ safe locks to protect allocation bitmaps 



It is supposed to be OK to call mthca_create_ah() and mthca_destroy_ah()
from any context.  However, for mem-full HCAs, these functions use the
mthca_alloc() and mthca_free() bitmap helpers, and those helpers use
non-IRQ-safe spin_lock() internally.  Lockdep correctly warns that
this could lead to a deadlock.  Fix this by changing mthca_alloc() and
mthca_free() to use spin_lock_irqsave().

Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent 22db37ec

drivers/infiniband/hw/mthca/mthca_allocator.c

+11 −4
Original line number Diff line number Diff line
@@ -41,9 +41,11 @@ 
/* Trivial bitmap-based allocator */

u32 mthca_alloc(struct mthca_alloc *alloc)

{

	unsigned long flags;

	u32 obj;



	spin_lock(&alloc->lock);

	spin_lock_irqsave(&alloc->lock, flags);



	obj = find_next_zero_bit(alloc->table, alloc->max, alloc->last);

	if (obj >= alloc->max) {

		alloc->top = (alloc->top + alloc->max) & alloc->mask;
@@ -56,19 +58,24 @@ u32 mthca_alloc(struct mthca_alloc *alloc) 
	} else

		obj = -1;



	spin_unlock(&alloc->lock);

	spin_unlock_irqrestore(&alloc->lock, flags);



	return obj;

}



void mthca_free(struct mthca_alloc *alloc, u32 obj)

{

	unsigned long flags;



	obj &= alloc->max - 1;

	spin_lock(&alloc->lock);



	spin_lock_irqsave(&alloc->lock, flags);



	clear_bit(obj, alloc->table);

	alloc->last = min(alloc->last, obj);

	alloc->top = (alloc->top + alloc->max) & alloc->mask;

	spin_unlock(&alloc->lock);



	spin_unlock_irqrestore(&alloc->lock, flags);

}



int mthca_alloc_init(struct mthca_alloc *alloc, u32 num, u32 mask,