Re: [PATCH rdma-next 3/3] RDMA/irdma: Fix potential overflow expression in irdma_prm_get_pbles

[Jason Gunthorpe <jgg@nvidia.com>]

On Tue, Jun 22, 2021 at 12:52:32PM -0500, Tatyana Nikolova wrote:
> From: Shiraz Saleem <shiraz.saleem@intel.com>
> 
> Coverity reports a signed 32-bit overflow on "1 << pprm->pble_shift" when
> used expression to compute bits_needed that expects 64bit, unsigned.
> 
> Fix this by using the 1ULL in the left shift operator and convert
> mem_size to u64.
> 
> Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
> Addresses-Coverity-ID: 1505157 ("Integer handling issues")
> Fixes: 915cc7ac0f8e ("RDMA/irdma: Add miscellaneous utility definitions")
> Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com>
> Signed-off-by: Tatyana Nikolova <tatyana.e.nikolova@intel.com>
>  drivers/infiniband/hw/irdma/pble.h  | 2 +-
>  drivers/infiniband/hw/irdma/utils.c | 4 ++--
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/infiniband/hw/irdma/pble.h b/drivers/infiniband/hw/irdma/pble.h
> index e4e635dc4fd9..e1b3b8118a2c 100644
> +++ b/drivers/infiniband/hw/irdma/pble.h
> @@ -121,7 +121,7 @@ enum irdma_status_code irdma_prm_add_pble_mem(struct irdma_pble_prm *pprm,
>  					      struct irdma_chunk *pchunk);
>  enum irdma_status_code
>  irdma_prm_get_pbles(struct irdma_pble_prm *pprm,
> -		    struct irdma_pble_chunkinfo *chunkinfo, u32 mem_size,
> +		    struct irdma_pble_chunkinfo *chunkinfo, u64 mem_size,
>  		    u64 **vaddr, u64 *fpm_addr);
>  void irdma_prm_return_pbles(struct irdma_pble_prm *pprm,
>  			    struct irdma_pble_chunkinfo *chunkinfo);
> diff --git a/drivers/infiniband/hw/irdma/utils.c b/drivers/infiniband/hw/irdma/utils.c
> index ea1df5918c11..e50b6f89b37e 100644
> +++ b/drivers/infiniband/hw/irdma/utils.c
> @@ -2314,7 +2314,7 @@ enum irdma_status_code irdma_prm_add_pble_mem(struct irdma_pble_prm *pprm,
>   */
>  enum irdma_status_code
>  irdma_prm_get_pbles(struct irdma_pble_prm *pprm,
> -		    struct irdma_pble_chunkinfo *chunkinfo, u32 mem_size,
> +		    struct irdma_pble_chunkinfo *chunkinfo, u64 mem_size,
>  		    u64 **vaddr, u64 *fpm_addr)
>  {
>  	u64 bits_needed;
> @@ -2326,7 +2326,7 @@ irdma_prm_get_pbles(struct irdma_pble_prm *pprm,
>  	*vaddr = NULL;
>  	*fpm_addr = 0;
>  
> -	bits_needed = (mem_size + (1 << pprm->pble_shift) - 1) >> pprm->pble_shift;
> +	bits_needed = (mem_size + BIT_ULL(pprm->pble_shift) - 1) >> pprm->pble_shift;

Isn't this just DIV_ROUND_UP_ULL() ?

Jason