The patch titled
Subject: maple_tree: do not preallocate nodes for slot stores
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
maple_tree-do-not-preallocate-nodes-for-slot-stores.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche…
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Sidhartha Kumar <sidhartha.kumar(a)oracle.com>
Subject: maple_tree: do not preallocate nodes for slot stores
Date: Wed, 13 Dec 2023 12:50:57 -0800
mas_preallocate() defaults to requesting 1 node for preallocation and then
,depending on the type of store, will update the request variable. There
isn't a check for a slot store type, so slot stores are preallocating the
default 1 node. Slot stores do not require any additional nodes, so add a
check for the slot store case that will bypass node_count_gfp(). Update
the tests to reflect that slot stores do not require allocations.
User visible effects of this bug include increased memory usage from the
unneeded node that was allocated.
Link: https://lkml.kernel.org/r/20231213205058.386589-1-sidhartha.kumar@oracle.com
Fixes: 0b8bb544b1a7 ("maple_tree: update mas_preallocate() testing")
Signed-off-by: Sidhartha Kumar <sidhartha.kumar(a)oracle.com>
Cc: Liam R. Howlett <Liam.Howlett(a)oracle.com>
Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org>
Cc: Peng Zhang <zhangpeng.00(a)bytedance.com>
Cc: <stable(a)vger.kernel.org> [6.6+]
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
lib/maple_tree.c | 11 +++++++++++
tools/testing/radix-tree/maple.c | 2 +-
2 files changed, 12 insertions(+), 1 deletion(-)
--- a/lib/maple_tree.c~maple_tree-do-not-preallocate-nodes-for-slot-stores
+++ a/lib/maple_tree.c
@@ -5501,6 +5501,17 @@ int mas_preallocate(struct ma_state *mas
mas_wr_end_piv(&wr_mas);
node_size = mas_wr_new_end(&wr_mas);
+
+ /* Slot store, does not require additional nodes */
+ if (node_size == wr_mas.node_end) {
+ /* reuse node */
+ if (!mt_in_rcu(mas->tree))
+ return 0;
+ /* shifting boundary */
+ if (wr_mas.offset_end - mas->offset == 1)
+ return 0;
+ }
+
if (node_size >= mt_slots[wr_mas.type]) {
/* Split, worst case for now. */
request = 1 + mas_mt_height(mas) * 2;
--- a/tools/testing/radix-tree/maple.c~maple_tree-do-not-preallocate-nodes-for-slot-stores
+++ a/tools/testing/radix-tree/maple.c
@@ -35538,7 +35538,7 @@ static noinline void __init check_preall
MT_BUG_ON(mt, mas_preallocate(&mas, ptr, GFP_KERNEL) != 0);
allocated = mas_allocated(&mas);
height = mas_mt_height(&mas);
- MT_BUG_ON(mt, allocated != 1);
+ MT_BUG_ON(mt, allocated != 0);
mas_store_prealloc(&mas, ptr);
MT_BUG_ON(mt, mas_allocated(&mas) != 0);
_
Patches currently in -mm which might be from sidhartha.kumar(a)oracle.com are
maple_tree-do-not-preallocate-nodes-for-slot-stores.patch
In serial_omap_rs485() RS485 support may be deactivated due to a missing
RTS GPIO. This is done by nullifying the ports rs485_supported struct.
After that however the serial_omap_rs485_supported struct is assigned to
the same structure unconditionally, which results in an unintended
reactivation of RS485 support.
Fix this by callling serial_omap_rs485() after the assignment of
rs485_supported.
Fixes: e2752ae3cfc9 ("serial: omap: Disallow RS-485 if rts-gpio is not specified")
Cc: stable(a)vger.kernel.org
Signed-off-by: Lino Sanfilippo <l.sanfilippo(a)kunbus.com>
---
drivers/tty/serial/omap-serial.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index ad4c1c5d0a7f..d9b2936308c4 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -1604,10 +1604,6 @@ static int serial_omap_probe(struct platform_device *pdev)
dev_info(up->port.dev, "no wakeirq for uart%d\n",
up->port.line);
- ret = serial_omap_probe_rs485(up, &pdev->dev);
- if (ret < 0)
- goto err_rs485;
-
sprintf(up->name, "OMAP UART%d", up->port.line);
up->port.mapbase = mem->start;
up->port.membase = base;
@@ -1622,6 +1618,10 @@ static int serial_omap_probe(struct platform_device *pdev)
DEFAULT_CLK_SPEED);
}
+ ret = serial_omap_probe_rs485(up, &pdev->dev);
+ if (ret < 0)
+ goto err_rs485;
+
up->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
up->calc_latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
cpu_latency_qos_add_request(&up->pm_qos_request, up->latency);
--
2.42.0
Some uart drivers specify a rs485_config() function and then decide later
to disable RS485 support for some reason (e.g. imx and ar933).
In these cases userspace may be able to activate RS485 via TIOCSRS485
nevertheless, since in uart_set_rs485_config() an existing rs485_config()
function indicates that RS485 is supported.
Make sure that this is not longer possible by checking the uarts
rs485_supported.flags instead and bailing out if SER_RS485_ENABLED is not
set.
Furthermore instead of returning an empty structure return -ENOTTY if the
RS485 configuration is requested via TIOCGRS485 but RS485 is not supported.
This has a small impact on userspace visibility but it is consistent with
the -ENOTTY error for TIOCGRS485.
Fixes: e849145e1fdd ("serial: ar933x: Fill in rs485_supported")
Fixes: 55e18c6b6d42 ("serial: imx: Remove serial_rs485 sanitization")
Cc: Shawn Guo <shawnguo(a)kernel.org>
Cc: Sascha Hauer <s.hauer(a)pengutronix.de>
Cc: stable(a)vger.kernel.org
Signed-off-by: Lino Sanfilippo <l.sanfilippo(a)kunbus.com>
---
drivers/tty/serial/serial_core.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 4eae1406cb6c..661074ab8edb 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1448,6 +1448,9 @@ static int uart_get_rs485_config(struct uart_port *port,
unsigned long flags;
struct serial_rs485 aux;
+ if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
+ return -ENOTTY;
+
uart_port_lock_irqsave(port, &flags);
aux = port->rs485;
uart_port_unlock_irqrestore(port, flags);
@@ -1465,7 +1468,7 @@ static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
int ret;
unsigned long flags;
- if (!port->rs485_config)
+ if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
return -ENOTTY;
if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
--
2.42.0