Hi Jakob, > -----Original Message----- > From: Jakob Koschel <jakobkoschel@xxxxxxxxx> > Sent: Friday, April 1, 2022 1:07 AM > To: Jonathan Cameron <jic23@xxxxxxxxxx> > Cc: Lars-Peter Clausen <lars@xxxxxxxxxx>; Dan Carpenter > <dan.carpenter@xxxxxxxxxx>; Jakob Koschel > <jakobkoschel@xxxxxxxxx>; linux-iio@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; Mike Rapoport <rppt@xxxxxxxxxx>; Brian > Johannesmeyer <bjohannesmeyer@xxxxxxxxx>; Cristiano Giuffrida > <c.giuffrida@xxxxx>; Bos, H.J. <h.j.bos@xxxxx> > Subject: [PATCH 1/3] iio: buffer: remove usage of list iterator variable > for list_for_each_entry_continue_reverse() > > [External] > > In preparation to limit the scope of the list iterator variable to the > list traversal loop, use a dedicated pointer to iterate through the > list [1]. > > Since that variable should not be used past the loop iteration, a > separate variable is used to 'remember the current location within the > loop'. > > To either continue iterating from that position or start a new > iteration (if the previous iteration was complete) list_prepare_entry() > is used. > > Link: https://urldefense.com/v3/__https://lore.kernel.org/all/CAHk- > =wgRr_D8CB-D9Kg- > c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@xxxxxxxxxxxxxx/__;!!A3Ni8CS0y > 2Y!q8llw5UCaMIsAU7tPtPDhwVor0wy032I7FJHv0VxBZksNuRJF04HjWe > 0XYG7OQ$ [1] > Signed-off-by: Jakob Koschel <jakobkoschel@xxxxxxxxx> > --- > drivers/iio/industrialio-buffer.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio- > buffer.c > index 208b5193c621..151a77c2affd 100644 > --- a/drivers/iio/industrialio-buffer.c > +++ b/drivers/iio/industrialio-buffer.c > @@ -1059,7 +1059,7 @@ static int iio_enable_buffers(struct iio_dev > *indio_dev, > struct iio_device_config *config) > { > struct iio_dev_opaque *iio_dev_opaque = > to_iio_dev_opaque(indio_dev); > - struct iio_buffer *buffer; > + struct iio_buffer *buffer, *tmp = NULL; > int ret; > > indio_dev->active_scan_mask = config->scan_mask; > @@ -1097,8 +1097,10 @@ static int iio_enable_buffers(struct iio_dev > *indio_dev, > > list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, > buffer_list) { > ret = iio_buffer_enable(buffer, indio_dev); > - if (ret) > + if (ret) { > + tmp = buffer; > goto err_disable_buffers; > + } > } > > if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) { > @@ -1125,6 +1127,7 @@ static int iio_enable_buffers(struct iio_dev > *indio_dev, > indio_dev->pollfunc); > } > err_disable_buffers: > + buffer = list_prepare_entry(tmp, &iio_dev_opaque- > >buffer_list, buffer_list); Ok, it's Friday so I might be seeing ghosts... But looking at 'list_prepare_entry()'... If tmp != NULL, then all goes well but if tmp == NULL, then we get list_entry(&iio_dev_opaque->buffer_list, struct iio_buffer, buffer_list) which would require 'struct iio_dev_opaque'. It looks like like 'list_prepare_entry()' assumes that pos and head are of the same type... Am I missing something? - Nuno Sá
