lkml.org 
[lkml]   [2019]   [Aug]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] scsi: mvumi: fix 32 bit shift of a u32 value


Am 13.08.2019 20:01, schrieb Colin King:
> From: Colin Ian King <colin.king@canonical.com>
>
> Currently the top 32 bits of a 64 bit address is being calculated
> by shifting a u32 twice by 16 bits and then being cast into a 64
> bit address. Shifting a u32 twice by 16 bits always ends up with
> a zero. Fix this by casting the u32 to a 64 bit address first
> and then shifting it 32 bits.
>
> Addresses-Coverity: ("Operands don't affect result")
> Fixes: f0c568a478f0 ("[SCSI] mvumi: Add Marvell UMI driver")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> drivers/scsi/mvumi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/mvumi.c b/drivers/scsi/mvumi.c
> index 8906aceda4c4..62df69f1e71e 100644
> --- a/drivers/scsi/mvumi.c
> +++ b/drivers/scsi/mvumi.c
> @@ -296,7 +296,7 @@ static void mvumi_delete_internal_cmd(struct mvumi_hba *mhba,
> sgd_getsz(mhba, m_sg, size);
>
> phy_addr = (dma_addr_t) m_sg->baseaddr_l |
> - (dma_addr_t) ((m_sg->baseaddr_h << 16) << 16);
> + (dma_addr_t) m_sg->baseaddr_h << 32;
>

All the casts make it hard to read, i would propose an alternativ version:
phy_addr = m_sg->baseaddr_h;
phy_addr <<= 32;
phy_addr |= m_sg->baseaddr_l;

JM2C and totaly untested.

re,
wh

> dma_free_coherent(&mhba->pdev->dev, size, cmd->data_buf,
> phy_addr);

\
 
 \ /
  Last update: 2019-08-14 09:19    [W:0.032 / U:14.060 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site