| Message ID | 1447115848-92621-1-git-send-email-computersforpeace@gmail.com |
|---|---|
| State | Accepted |
| Headers | show |
On 15-11-09 04:37 PM, Brian Norris wrote: > If multiple NAND chips are registered to the same controller, then when > rebooting the system, the first one will grab the controller lock, while > the second will wait forever for the first one to release it. i.e., a > classic deadlock. > > This problem was solved for a similar case (suspend/resume) back in > commit 6b0d9a841249 ("mtd: nand: fix multi-chip suspend problem"), and > the shutdown state really isn't much different for us, so rather than > adding a new special case to nand_get_device(), we can just overload the > FL_PM_SUSPENDED state. > > Now, multiple chips can "get" the same controller lock (preventing > further I/O), while we still allow other chips to pass through > nand_shutdown(). > > Original report: > http://thread.gmane.org/gmane.linux.drivers.mtd/59726 > http://lists.infradead.org/pipermail/linux-mtd/2015-July/059992.html > > Fixes: 72ea403669c7 ("mtd: nand: added nand_shutdown") > Reported-by: Andrew E. Mileski <andrewm@isoar.ca> > Signed-off-by: Brian Norris <computersforpeace@gmail.com> > Cc: Scott Branden <sbranden@broadcom.com> > Cc: Andrew E. Mileski <andrewm@isoar.ca> > --- > I only compile-tested > > If we get proper tests, this is probably 4.4 material I reviewed the code in nand_get_device and it looks sane whether FL_SHUTDOWN or PL_PM_SUSPENDED is called. Acked-by: Scott Branden <sbranden@broadcom.com> > > drivers/mtd/nand/nand_base.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c > index cc74142938b0..ece544efccc3 100644 > --- a/drivers/mtd/nand/nand_base.c > +++ b/drivers/mtd/nand/nand_base.c > @@ -3110,7 +3110,7 @@ static void nand_resume(struct mtd_info *mtd) > */ > static void nand_shutdown(struct mtd_info *mtd) > { > - nand_get_device(mtd, FL_SHUTDOWN); > + nand_get_device(mtd, FL_PM_SUSPENDED); > } > > /* Set default functions */ >
On Mon, 9 Nov 2015 16:37:28 -0800 Brian Norris <computersforpeace@gmail.com> wrote: > If multiple NAND chips are registered to the same controller, then when > rebooting the system, the first one will grab the controller lock, while > the second will wait forever for the first one to release it. i.e., a > classic deadlock. > > This problem was solved for a similar case (suspend/resume) back in > commit 6b0d9a841249 ("mtd: nand: fix multi-chip suspend problem"), and > the shutdown state really isn't much different for us, so rather than > adding a new special case to nand_get_device(), we can just overload the > FL_PM_SUSPENDED state. > > Now, multiple chips can "get" the same controller lock (preventing > further I/O), while we still allow other chips to pass through > nand_shutdown(). > > Original report: > http://thread.gmane.org/gmane.linux.drivers.mtd/59726 > http://lists.infradead.org/pipermail/linux-mtd/2015-July/059992.html > > Fixes: 72ea403669c7 ("mtd: nand: added nand_shutdown") > Reported-by: Andrew E. Mileski <andrewm@isoar.ca> > Signed-off-by: Brian Norris <computersforpeace@gmail.com> > Cc: Scott Branden <sbranden@broadcom.com> > Cc: Andrew E. Mileski <andrewm@isoar.ca> Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com> > --- > I only compile-tested > > If we get proper tests, this is probably 4.4 material > > drivers/mtd/nand/nand_base.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c > index cc74142938b0..ece544efccc3 100644 > --- a/drivers/mtd/nand/nand_base.c > +++ b/drivers/mtd/nand/nand_base.c > @@ -3110,7 +3110,7 @@ static void nand_resume(struct mtd_info *mtd) > */ > static void nand_shutdown(struct mtd_info *mtd) > { > - nand_get_device(mtd, FL_SHUTDOWN); > + nand_get_device(mtd, FL_PM_SUSPENDED); > } > > /* Set default functions */
On Mon, Nov 09, 2015 at 04:37:28PM -0800, Brian Norris wrote: > If multiple NAND chips are registered to the same controller, then when > rebooting the system, the first one will grab the controller lock, while > the second will wait forever for the first one to release it. i.e., a > classic deadlock. > > This problem was solved for a similar case (suspend/resume) back in > commit 6b0d9a841249 ("mtd: nand: fix multi-chip suspend problem"), and > the shutdown state really isn't much different for us, so rather than > adding a new special case to nand_get_device(), we can just overload the > FL_PM_SUSPENDED state. > > Now, multiple chips can "get" the same controller lock (preventing > further I/O), while we still allow other chips to pass through > nand_shutdown(). > > Original report: > http://thread.gmane.org/gmane.linux.drivers.mtd/59726 > http://lists.infradead.org/pipermail/linux-mtd/2015-July/059992.html > > Fixes: 72ea403669c7 ("mtd: nand: added nand_shutdown") > Reported-by: Andrew E. Mileski <andrewm@isoar.ca> > Signed-off-by: Brian Norris <computersforpeace@gmail.com> > Cc: Scott Branden <sbranden@broadcom.com> > Cc: Andrew E. Mileski <andrewm@isoar.ca> Pushed to linux-mtd.git
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index cc74142938b0..ece544efccc3 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -3110,7 +3110,7 @@ static void nand_resume(struct mtd_info *mtd) */ static void nand_shutdown(struct mtd_info *mtd) { - nand_get_device(mtd, FL_SHUTDOWN); + nand_get_device(mtd, FL_PM_SUSPENDED); } /* Set default functions */
If multiple NAND chips are registered to the same controller, then when rebooting the system, the first one will grab the controller lock, while the second will wait forever for the first one to release it. i.e., a classic deadlock. This problem was solved for a similar case (suspend/resume) back in commit 6b0d9a841249 ("mtd: nand: fix multi-chip suspend problem"), and the shutdown state really isn't much different for us, so rather than adding a new special case to nand_get_device(), we can just overload the FL_PM_SUSPENDED state. Now, multiple chips can "get" the same controller lock (preventing further I/O), while we still allow other chips to pass through nand_shutdown(). Original report: http://thread.gmane.org/gmane.linux.drivers.mtd/59726 http://lists.infradead.org/pipermail/linux-mtd/2015-July/059992.html Fixes: 72ea403669c7 ("mtd: nand: added nand_shutdown") Reported-by: Andrew E. Mileski <andrewm@isoar.ca> Signed-off-by: Brian Norris <computersforpeace@gmail.com> Cc: Scott Branden <sbranden@broadcom.com> Cc: Andrew E. Mileski <andrewm@isoar.ca> --- I only compile-tested If we get proper tests, this is probably 4.4 material drivers/mtd/nand/nand_base.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)