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