Input: evdev - fall back to vmalloc for client event buffer (92eb77d0) · Commits · 戴 / test

evdev always tries to allocate the event buffer for clients using kzalloc rather than vmalloc, presumably to avoid mapping overhead where possible. However, drivers like bcm5974, which claims support for reporting 16 fingers simultaneously, can have an extraordinarily large buffer. The resultant contiguous order-4 allocation attempt fails due to fragmentation, and the device is thus unusable until reboot. Try kzalloc if we can to avoid the mapping overhead, but if that fails, fall back to vzalloc. Signed-off-by:

Daniel Stone <daniels@collabora.com> Signed-off-by:

Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/evdev.c

+12 −4

Original line number	Diff line number	Diff line
		@@ -18,6 +18,8 @@
		#include <linux/poll.h>
		#include <linux/sched.h>
		#include <linux/slab.h>
		#include <linux/vmalloc.h>
		#include <linux/mm.h>
		#include <linux/module.h>
		#include <linux/init.h>
		#include <linux/input/mt.h>
		@@ -369,6 +371,10 @@ static int evdev_release(struct inode inode, struct file file)
		mutex_unlock(&evdev->mutex);

		evdev_detach_client(evdev, client);

		if (is_vmalloc_addr(client))
		vfree(client);
		else
		kfree(client);

		evdev_close_device(evdev);
		@@ -389,12 +395,14 @@ static int evdev_open(struct inode inode, struct file file)
		{
		struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev);
		unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev);
		unsigned int size = sizeof(struct evdev_client) +
		bufsize * sizeof(struct input_event);
		struct evdev_client *client;
		int error;

		client = kzalloc(sizeof(struct evdev_client) +
		bufsize * sizeof(struct input_event),
		GFP_KERNEL);
		client = kzalloc(size, GFP_KERNEL \| __GFP_NOWARN);
		if (!client)
		client = vzalloc(size);
		if (!client)
		return -ENOMEM;

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