On Thu, Mar 7, 2019 at 3:19 PM Nathan Chancellor <natechancellor@xxxxxxxxx> wrote: > > When building with -Wsometimes-uninitialized, Clang warns: > > drivers/scsi/gdth.c:3662:6: warning: variable 'paddr' is used > uninitialized whenever 'if' condition is false > [-Wsometimes-uninitialized] > > Don't attempt to call dma_free_coherent when buf is NULL (meaning that > we never called dma_alloc_coherent and initialized paddr), which avoids > this warning. > > Link: https://github.com/ClangBuiltLinux/linux/issues/402 > Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx> > --- > drivers/scsi/gdth.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/scsi/gdth.c b/drivers/scsi/gdth.c > index e7f1dd4f3b66..0ca9b4393770 100644 > --- a/drivers/scsi/gdth.c > +++ b/drivers/scsi/gdth.c > @@ -3697,8 +3697,9 @@ static int ioc_general(void __user *arg, char *cmnd) > > rval = 0; > out_free_buf: > - dma_free_coherent(&ha->pdev->dev, gen.data_len + gen.sense_len, buf, > - paddr); > + if (buf) > + dma_free_coherent(&ha->pdev->dev, gen.data_len + gen.sense_len, > + buf, paddr); > return rval; > } > > -- > 2.21.0 > Alternatively, paddr is a dma_addr_t defined in include/linux/types.h: #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT typedef u64 dma_addr_t; #else typedef u32 dma_addr_t; #endif Just initializing it to zero might be simpler than complicating the control flow of this function further. Thoughts? diff --git a/drivers/scsi/gdth.c b/drivers/scsi/gdth.c index e7f1dd4f3b66..5a3f849ebf64 100644 --- a/drivers/scsi/gdth.c +++ b/drivers/scsi/gdth.c @@ -3643,7 +3643,7 @@ static int ioc_general(void __user *arg, char *cmnd) gdth_ioctl_general gen; gdth_ha_str *ha; char *buf = NULL; - dma_addr_t paddr; + dma_addr_t paddr = 0U; int rval; if (copy_from_user(&gen, arg, sizeof(gdth_ioctl_general))) -- Thanks, ~Nick Desaulniers
