| Message ID | 1413963581-24019-1-git-send-email-geert@linux-m68k.org |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Geert Uytterhoeven <geert@linux-m68k.org> Date: Wed, 22 Oct 2014 09:39:41 +0200 > drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c: In function ‘xgene_enet_ecc_init’: > drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c:126: warning: ‘data’ may be used uninitialized in this function > > Depending on the arbitrary value on the stack, the loop may terminate > too early, and cause a bogus -ENODEV failure. > > Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> > --- > v2: Rewrite the loop instead of pre-initializing data. I hate to be a pest, but like the other patch of your's I think a do { } while() works best here because the intent is clearly to run the loop at least once, right?
On Wed, Oct 22, 2014 at 9:34 PM, David Miller <davem@davemloft.net> wrote: > From: Geert Uytterhoeven <geert@linux-m68k.org> > Date: Wed, 22 Oct 2014 09:39:41 +0200 > >> drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c: In function ‘xgene_enet_ecc_init’: >> drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c:126: warning: ‘data’ may be used uninitialized in this function >> >> Depending on the arbitrary value on the stack, the loop may terminate >> too early, and cause a bogus -ENODEV failure. >> >> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> >> --- >> v2: Rewrite the loop instead of pre-initializing data. > > I hate to be a pest, but like the other patch of your's I think > a do { } while() works best here because the intent is clearly > to run the loop at least once, right? I wanted to avoid checking for "data != ~0U" twice: once to abort the loop, and once to check if a timeout happened. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Oct 22, 2014 at 10:12 PM, David Miller <davem@davemloft.net> wrote: > From: Geert Uytterhoeven <geert@linux-m68k.org> > Date: Wed, 22 Oct 2014 21:50:06 +0200 > >> On Wed, Oct 22, 2014 at 9:34 PM, David Miller <davem@davemloft.net> wrote: >>> From: Geert Uytterhoeven <geert@linux-m68k.org> >>> Date: Wed, 22 Oct 2014 09:39:41 +0200 >>> >>>> drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c: In function ‘xgene_enet_ecc_init’: >>>> drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c:126: warning: ‘data’ may be used uninitialized in this function >>>> >>>> Depending on the arbitrary value on the stack, the loop may terminate >>>> too early, and cause a bogus -ENODEV failure. >>>> >>>> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> >>>> --- >>>> v2: Rewrite the loop instead of pre-initializing data. >>> >>> I hate to be a pest, but like the other patch of your's I think >>> a do { } while() works best here because the intent is clearly >>> to run the loop at least once, right? >> >> I wanted to avoid checking for "data != ~0U" twice: once to abort the loop, >> and once to check if a timeout happened. > > Hmmm: > > do { > usleep_range(...); > data = ...(); > if (data == ~0) > return 0; > } while (++i < 10); > > netdev_err(...); > return -ENODEV; > > Why would you have to check data twice?
On Wed, Oct 22, 2014 at 10:12 PM, David Miller <davem@davemloft.net> wrote: > From: Geert Uytterhoeven <geert@linux-m68k.org> > Date: Wed, 22 Oct 2014 21:50:06 +0200 > >> On Wed, Oct 22, 2014 at 9:34 PM, David Miller <davem@davemloft.net> wrote: >>> From: Geert Uytterhoeven <geert@linux-m68k.org> >>> Date: Wed, 22 Oct 2014 09:39:41 +0200 >>> >>>> drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c: In function ‘xgene_enet_ecc_init’: >>>> drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c:126: warning: ‘data’ may be used uninitialized in this function >>>> >>>> Depending on the arbitrary value on the stack, the loop may terminate >>>> too early, and cause a bogus -ENODEV failure. >>>> >>>> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> >>>> --- >>>> v2: Rewrite the loop instead of pre-initializing data. >>> >>> I hate to be a pest, but like the other patch of your's I think >>> a do { } while() works best here because the intent is clearly >>> to run the loop at least once, right? >> >> I wanted to avoid checking for "data != ~0U" twice: once to abort the loop, >> and once to check if a timeout happened. > > Hmmm: > > do { > usleep_range(...); > data = ...(); > if (data == ~0) > return 0; > } while (++i < 10); > > netdev_err(...); > return -ENODEV; > > Why would you have to check data twice? Yes, that would work to. Feel free to do s/for (i = 0; i < 10; i++)/do/ and s/}/} while (++i < 10);/ Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c b/drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c index e6d24c2101982444..2a497b38ed420495 100644 --- a/drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c +++ b/drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c @@ -127,17 +127,15 @@ static int xgene_enet_ecc_init(struct xgene_enet_pdata *p) int i; xgene_enet_wr_diag_csr(p, ENET_CFG_MEM_RAM_SHUTDOWN_ADDR, 0); - for (i = 0; i < 10 && data != ~0U ; i++) { + for (i = 0; i < 10; i++) { usleep_range(100, 110); data = xgene_enet_rd_diag_csr(p, ENET_BLOCK_MEM_RDY_ADDR); + if (data == ~0U) + return 0; } - if (data != ~0U) { - netdev_err(ndev, "Failed to release memory from shutdown\n"); - return -ENODEV; - } - - return 0; + netdev_err(ndev, "Failed to release memory from shutdown\n"); + return -ENODEV; } static void xgene_enet_config_ring_if_assoc(struct xgene_enet_pdata *p)
drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c: In function ‘xgene_enet_ecc_init’: drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c:126: warning: ‘data’ may be used uninitialized in this function Depending on the arbitrary value on the stack, the loop may terminate too early, and cause a bogus -ENODEV failure. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> --- v2: Rewrite the loop instead of pre-initializing data. drivers/net/ethernet/apm/xgene/xgene_enet_sgmac.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-)