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um: vector: Reduce stack usage in vector_eth_configure()

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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: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202506221017.WtB7Usua-lkp@intel.com/
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20250623110829.314864-1-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Tiwei Bie 2025-06-23 19:08:29 +08:00 committed by Johannes Berg
parent 8948941276
commit 2d65fc13be
1 changed files with 13 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
arch/um/drivers/vector_kern.c
View File

@ -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
* 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
});
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
*/
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);