Re: [PATCH] amdkfd: use sizeof(long) granularity for the pasid bitmask

From: Oded Gabbay
Date: Thu Dec 04 2014 - 07:21:47 EST

On 12/03/2014 04:26 PM, Sasha Levin wrote:
All the bit operations (such as find_first_zero_bit()) read sizeof(long) bytes
at a time. If we allocated less than sizeof(long) bytes for the bitmask we
would be accessing invalid memory when working with the bitmask.

Change the allocator to allocate sizeof(long) multiples for the bitmask.

Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
drivers/gpu/drm/amd/amdkfd/kfd_pasid.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_pasid.c b/drivers/gpu/drm/amd/amdkfd/kfd_pasid.c
index 2458ab7..71699ad 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_pasid.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_pasid.c
@@ -32,8 +32,7 @@ int kfd_pasid_init(void)
pasid_limit = max_num_of_processes;

- pasid_bitmap = kzalloc(DIV_ROUND_UP(pasid_limit, BITS_PER_BYTE),
+ pasid_bitmap = kzalloc(BITS_TO_LONGS(pasid_limit), GFP_KERNEL);
if (!pasid_bitmap)
return -ENOMEM;

Applied to my -next tree.

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