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([2001:a61:3456:4e01:6ae:b55a:bd1d:57fc]) by smtp.gmail.com with ESMTPSA id gq7-20020a170906e24700b00a3f3d0d30c8sm2195942ejb.213.2024.02.26.00.48.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Feb 2024 00:48:12 -0800 (PST) Message-ID: <7640e4d66d1f5c29987a7c79f68c9b2c719a6dcb.camel@gmail.com> Subject: Re: [PATCH v2 2/5] iio: events: move to the cleanup.h magic From: Nuno =?ISO-8859-1?Q?S=E1?= To: Jonathan Cameron , Nuno Sa Cc: linux-iio@vger.kernel.org, Lars-Peter Clausen , "Fabio M. De Francesco" Date: Mon, 26 Feb 2024 09:48:11 +0100 In-Reply-To: <20240225123531.020e875f@jic23-huawei> References: <20240223-iio-use-cleanup-magic-v2-0-f6b4848c1f34@analog.com> <20240223-iio-use-cleanup-magic-v2-2-f6b4848c1f34@analog.com> <20240225123531.020e875f@jic23-huawei> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.50.4 (3.50.4-1.fc39) Precedence: bulk X-Mailing-List: linux-iio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Sun, 2024-02-25 at 12:35 +0000, Jonathan Cameron wrote: > On Fri, 23 Feb 2024 13:43:45 +0100 > Nuno Sa wrote: >=20 > > Use the new cleanup magic for handling mutexes in IIO. This allows us t= o > > greatly simplify some code paths. > >=20 > > Signed-off-by: Nuno Sa > > --- > > =C2=A0drivers/iio/industrialio-event.c | 42 +++++++++++++++++----------= ------------- > > =C2=A01 file changed, 18 insertions(+), 24 deletions(-) > >=20 > > diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industriali= o-event.c > > index 910c1f14abd5..ef3cecbce915 100644 > > --- a/drivers/iio/industrialio-event.c > > +++ b/drivers/iio/industrialio-event.c > > @@ -7,6 +7,7 @@ > > =C2=A0 */ > > =C2=A0 > > =C2=A0#include > > +#include > > =C2=A0#include > > =C2=A0#include > > =C2=A0#include > > @@ -146,11 +147,10 @@ static ssize_t iio_event_chrdev_read(struct file = *filep, > > =C2=A0 return -ENODEV; > > =C2=A0 } > > =C2=A0 > > - if (mutex_lock_interruptible(&ev_int->read_lock)) > > - return -ERESTARTSYS; > > - ret =3D kfifo_to_user(&ev_int->det_events, buf, count, &copied); > > - mutex_unlock(&ev_int->read_lock); > > - > > + scoped_cond_guard(mutex_intr, return -ERESTARTSYS, > > + =C2=A0 &ev_int->read_lock) > > + ret =3D kfifo_to_user(&ev_int->det_events, buf, count, > > + =C2=A0=C2=A0=C2=A0 &copied); >=20 > > =C2=A0 if (ret) > > =C2=A0 return ret; > > =C2=A0 > > @@ -198,28 +198,22 @@ static int iio_event_getfd(struct iio_dev *indio_= dev) > > =C2=A0 if (ev_int =3D=3D NULL) > > =C2=A0 return -ENODEV; > > =C2=A0 > > - fd =3D mutex_lock_interruptible(&iio_dev_opaque->mlock); > > - if (fd) > > - return fd; > > + scoped_cond_guard(mutex_intr, return -EINTR, &iio_dev_opaque->mlock) = { >=20 > Maybe we want to wait for > cond_guard() that Fabio has been working on to land > https://lore.kernel.org/all/20240217105904.1912368-2-fabio.maria.de.franc= esco@linux.intel.com/ > Not sure if it will make the merge window and I don't want to hold this a= whole > cycle if it doesn't. Oh nice, I was wondering about something like this as my first reaction was= also to have something like guard(). >=20 > In many cases I find the scoped version easier to read, but sometimes it = makes > things > a little messy and for cases like this where it's taken for nearly the wh= ole > function > (other than some input parameter checks) the guard() form is nice and > cond_guard() as similar advantages. Agreed. I'll hold a bit to see if it get's merged... >=20 > If I didn't have a few other requests for changes I'd just have picked th= is > and we could have coped with the slightly less elegant change set. >=20 >=20 > > + if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) > > + return -EBUSY; > > =C2=A0 > > - if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) { > > - fd =3D -EBUSY; > > - goto unlock; > > + iio_device_get(indio_dev); > > + > > + fd =3D anon_inode_getfd("iio:event", &iio_event_chrdev_fileops, > > + =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 indio_dev, O_RDONLY | O_CLOEXEC); > > + if (fd < 0) { > > + clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags); > > + iio_device_put(indio_dev); > Given this is an error path, I think it would now be nicer to do > return fd; Alright... - Nuno S=C3=A1