[PATCH 1/3] tty: port: replace get_zeroed_page() with kzalloc()
From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
Date: 2026-08-30 07:49:51
Also in:
linux-mm, linux-serial, lkml
Subsystem:
the rest, tty layer and serial drivers · Maintainers:
Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
tty_port_alloc_xmit_buf() allocates the transmit buffer of a tty port. The buffer only backs the port's kfifo, the data being sent is copied in and out of it. This buffer can be allocated with kmalloc() as there's nothing special about it to go directly to the page allocator. kmalloc() provides a better API that does not require ugly casts and kfree() does not need to know the size of the freed object. Performance difference between kmalloc() and __get_free_pages() is not measurable as both allocators take an object/page from a per-CPU list for fast path allocations. For the slow path the performance is anyway determined by the amount of reclaim involved rather than by what allocator is used. Replace use of get_zeroed_page() with kzalloc() and free_page() with kfree(). Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redhat.com (local) Assisted-by: copilot:claude-opus Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> --- drivers/tty/tty_port.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 54359310e293..44122921fc45 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c@@ -240,13 +240,13 @@ EXPORT_SYMBOL_GPL(tty_port_unregister_device); int tty_port_alloc_xmit_buf(struct tty_port *port) { - /* We may sleep in get_zeroed_page() */ + /* We may sleep in kzalloc() */ guard(mutex)(&port->buf_mutex); if (port->xmit_buf) return 0; - port->xmit_buf = (u8 *)get_zeroed_page(GFP_KERNEL); + port->xmit_buf = kzalloc(PAGE_SIZE, GFP_KERNEL); if (port->xmit_buf == NULL) return -ENOMEM;
@@ -259,7 +259,7 @@ EXPORT_SYMBOL(tty_port_alloc_xmit_buf); void tty_port_free_xmit_buf(struct tty_port *port) { guard(mutex)(&port->buf_mutex); - free_page((unsigned long)port->xmit_buf); + kfree(port->xmit_buf); port->xmit_buf = NULL; INIT_KFIFO(port->xmit_fifo); }
@@ -288,7 +288,7 @@ static void tty_port_destructor(struct kref *kref) /* check if last port ref was dropped before tty release */ if (WARN_ON(port->itty)) return; - free_page((unsigned long)port->xmit_buf); + kfree(port->xmit_buf); tty_port_destroy(port); if (port->ops && port->ops->destruct) port->ops->destruct(port);
--
2.53.0