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From: Johannes Berg <johannes@sipsolutions.net>
To: Richard Weinberger <richard@nod.at>, linux-um@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, anton.ivanov@cambridgegreys.com
Subject: Re: [PATCH 2/4] um: os_set_fd_block: Return old blocking mode
Date: Tue, 04 Jan 2022 10:00:25 +0100	[thread overview]
Message-ID: <5fdb10e93535d83d208682e2eb5514fa1d5b6240.camel@sipsolutions.net> (raw)
In-Reply-To: <20220101215810.13260-3-richard@nod.at>

On Sat, 2022-01-01 at 22:58 +0100, Richard Weinberger wrote:
> This will be needed when we restore the old mode upon exit.
> The function now returns < 0 in case of an error, 1 if O_NONBLOCK
> was set, 0 otherwise.
> 
> +++ b/arch/um/drivers/chan_user.c
> @@ -257,7 +257,7 @@ static int winch_tramp(int fd, struct tty_port *port, int *fd_out,
>  	}
>  
>  	err = os_set_fd_block(*fd_out, 0);
> -	if (err) {
> +	if (err < 0) {
>  		printk(UM_KERN_ERR "winch_tramp: failed to set thread_fd "
>  		       "non-blocking.\n");
>  		goto out_close;

This does 'return err' afterwards, which then changes the logic from 0
to 1, which seems wrong - especially given that it gets passed further
elsewhere as a pid, which seems very questionable in the first place,
but at least 1 would be valid pid unlike 0?

IOW, I think you need

-	return err;
+	return 0;

a couple of lines later.

johannes

WARNING: multiple messages have this Message-ID (diff)
From: Johannes Berg <johannes@sipsolutions.net>
To: Richard Weinberger <richard@nod.at>, linux-um@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, anton.ivanov@cambridgegreys.com
Subject: Re: [PATCH 2/4] um: os_set_fd_block: Return old blocking mode
Date: Tue, 04 Jan 2022 10:00:25 +0100	[thread overview]
Message-ID: <5fdb10e93535d83d208682e2eb5514fa1d5b6240.camel@sipsolutions.net> (raw)
In-Reply-To: <20220101215810.13260-3-richard@nod.at>

On Sat, 2022-01-01 at 22:58 +0100, Richard Weinberger wrote:
> This will be needed when we restore the old mode upon exit.
> The function now returns < 0 in case of an error, 1 if O_NONBLOCK
> was set, 0 otherwise.
> 
> +++ b/arch/um/drivers/chan_user.c
> @@ -257,7 +257,7 @@ static int winch_tramp(int fd, struct tty_port *port, int *fd_out,
>  	}
>  
>  	err = os_set_fd_block(*fd_out, 0);
> -	if (err) {
> +	if (err < 0) {
>  		printk(UM_KERN_ERR "winch_tramp: failed to set thread_fd "
>  		       "non-blocking.\n");
>  		goto out_close;

This does 'return err' afterwards, which then changes the logic from 0
to 1, which seems wrong - especially given that it gets passed further
elsewhere as a pid, which seems very questionable in the first place,
but at least 1 would be valid pid unlike 0?

IOW, I think you need

-	return err;
+	return 0;

a couple of lines later.

johannes

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  reply	other threads:[~2022-01-04  9:00 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-01 21:58 [PATCH 0/4] um: Assorted console related fixes Richard Weinberger
2022-01-01 21:58 ` Richard Weinberger
2022-01-01 21:58 ` [PATCH 1/4] um: Run console exit code also upon kernel panic Richard Weinberger
2022-01-01 21:58   ` Richard Weinberger
2022-01-04  5:58   ` kernel test robot
2022-01-04  8:56   ` Johannes Berg
2022-01-04  8:56     ` Johannes Berg
2022-01-01 21:58 ` [PATCH 2/4] um: os_set_fd_block: Return old blocking mode Richard Weinberger
2022-01-01 21:58   ` Richard Weinberger
2022-01-04  9:00   ` Johannes Berg [this message]
2022-01-04  9:00     ` Johannes Berg
2022-01-01 21:58 ` [PATCH 3/4] um: chan: Restore blocking mode upon exit Richard Weinberger
2022-01-01 21:58   ` Richard Weinberger
2022-01-01 21:58 ` [PATCH 4/4] um: irq: Restore O_ASYNC " Richard Weinberger
2022-01-01 21:58   ` Richard Weinberger
2022-01-04  9:02   ` Johannes Berg
2022-01-04  9:02     ` Johannes Berg
2022-03-09  5:29 ` [PATCH 0/4] um: Assorted console related fixes Glenn Washburn
2022-03-09  8:35   ` Richard Weinberger
2022-03-09 16:13     ` Randy Dunlap
2022-03-09 16:21       ` Richard Weinberger
2022-03-09 16:48         ` Randy Dunlap
2022-03-10 18:21     ` Glenn Washburn
2022-04-04 21:41       ` Richard Weinberger
2022-06-06 23:16         ` Glenn Washburn
2022-06-07  8:22           ` Johannes Berg
2022-06-07 15:10             ` Glenn Washburn

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