Commit 2d65fc13 authored by Tiwei Bie's avatar Tiwei Bie Committed by Johannes Berg
Browse files

um: vector: Reduce stack usage in vector_eth_configure() 



When compiling with clang (19.1.7), initializing *vp using a compound
literal may result in excessive stack usage. Fix it by initializing the
required fields of *vp individually.

Without this patch:

$ objdump -d arch/um/drivers/vector_kern.o | ./scripts/checkstack.pl x86_64 0
...
0x0000000000000540 vector_eth_configure [vector_kern.o]:1472
...

With this patch:

$ objdump -d arch/um/drivers/vector_kern.o | ./scripts/checkstack.pl x86_64 0
...
0x0000000000000540 vector_eth_configure [vector_kern.o]:208
...

Reported-by: default avatarkernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202506221017.WtB7Usua-lkp@intel.com/


Signed-off-by: default avatarTiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20250623110829.314864-1-tiwei.btw@antgroup.com


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 89489412

arch/um/drivers/vector_kern.c

+13 −29
Original line number Diff line number Diff line
@@ -1625,35 +1625,19 @@ static void vector_eth_configure( 


	device->dev = dev;



	*vp = ((struct vector_private)

		{

		.list			= LIST_HEAD_INIT(vp->list),

		.dev			= dev,

		.unit			= n,

		.options		= get_transport_options(def),

		.rx_irq			= 0,

		.tx_irq			= 0,

		.parsed			= def,

		.max_packet		= get_mtu(def) + ETH_HEADER_OTHER,

		/* TODO - we need to calculate headroom so that ip header

	INIT_LIST_HEAD(&vp->list);

	vp->dev		= dev;

	vp->unit	= n;

	vp->options	= get_transport_options(def);

	vp->parsed	= def;

	vp->max_packet	= get_mtu(def) + ETH_HEADER_OTHER;

	/*

	 * TODO - we need to calculate headroom so that ip header

	 * is 16 byte aligned all the time

	 */

		.headroom		= get_headroom(def),

		.form_header		= NULL,

		.verify_header		= NULL,

		.header_rxbuffer	= NULL,

		.header_txbuffer	= NULL,

		.header_size		= 0,

		.rx_header_size		= 0,

		.rexmit_scheduled	= false,

		.opened			= false,

		.transport_data		= NULL,

		.in_write_poll		= false,

		.coalesce		= 2,

		.req_size		= get_req_size(def),

		.in_error		= false,

		.bpf			= NULL

	});

	vp->headroom	= get_headroom(def);

	vp->coalesce	= 2;

	vp->req_size	= get_req_size(def);



	dev->features = dev->hw_features = (NETIF_F_SG | NETIF_F_FRAGLIST);

	INIT_WORK(&vp->reset_tx, vector_reset_tx);