* Re: [Patch] Signedness issue in drivers/net/3c515.c
[not found] <1156009077.18374.1.camel@alice>
@ 2006-08-21 21:05 ` Andrew Morton
2006-08-21 22:13 ` Alan Cox
0 siblings, 1 reply; 2+ messages in thread
From: Andrew Morton @ 2006-08-21 21:05 UTC (permalink / raw)
To: Eric Sesterhenn; +Cc: linux-kernel, netdev, Jeff Garzik
On Sat, 19 Aug 2006 19:37:57 +0200
Eric Sesterhenn <snakebyte@gmx.de> wrote:
> while playing with gcc 4.1 -Wextra warnings, I came across this one:
>
> drivers/net/3c515.c:1027: warning: comparison of unsigned expression >= 0 is always true
>
> Since i is unsigned the >= 0 check in the for loop is always true,
> so we might spin there forever unless the if condition triggers.
> Since i is only used in this loop, this patch changes it to
> an integer.
>
> Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
>
> --- linux-2.6.18-rc4/drivers/net/3c515.c.orig 2006-08-19 19:35:04.000000000 +0200
> +++ linux-2.6.18-rc4/drivers/net/3c515.c 2006-08-19 19:35:14.000000000 +0200
> @@ -1003,7 +1003,8 @@ static int corkscrew_start_xmit(struct s
> /* Calculate the next Tx descriptor entry. */
> int entry = vp->cur_tx % TX_RING_SIZE;
> struct boom_tx_desc *prev_entry;
> - unsigned long flags, i;
> + unsigned long flags;
> + int i;
>
> if (vp->tx_full) /* No room to transmit with */
> return 1;
Which affects this loop:
/* Wait for the stall to complete. */
for (i = 20; i >= 0; i--)
if ((inw(ioaddr + EL3_STATUS) & CmdInProgress) == 0)
break;
Your fix will convert this indefinit wait into a bounded one. It might
cause the driver to malfunction.
Given that our pool of 3c515 testers is less than enormous, a more prudent
change might be to remove `i' and simply formalise the existing behaviour
into a while(1) loop.
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