[PATCH] scsi: bfa: reduce kernel stack usage in bfa_fcs_lport_fdmi_build_portattr_block

[PATCH] scsi: bfa: reduce kernel stack usage in bfa_fcs_lport_fdmi_build_portattr_block

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

bfa_fcs_fdmi_get_portattr() gets inlined into multiple places and has two
fairly large variables on the stack, to the point of causing a warning
in some randconfig builds:

drivers/scsi/bfa/bfa_fcs_lport.c:2198:1: error: stack frame size (1560) exceeds limit (1280) in 'bfa_fcs_lport_fdmi_build_portattr_block' [-Werror,-Wframe-larger-than]
 2198 | bfa_fcs_lport_fdmi_build_portattr_block(struct bfa_fcs_lport_fdmi_s *fdmi,
      | ^
drivers/scsi/bfa/bfa_fcs_lport.c:1856:1: error: stack frame size (1600) exceeds limit (1280) in 'bfa_fcs_lport_fdmi_build_rhba_pyld' [-Werror,-Wframe-larger-than]
 1856 | bfa_fcs_lport_fdmi_build_rhba_pyld(struct bfa_fcs_lport_fdmi_s *fdmi, u8 *pyld)
      | ^

Mark the inner function as noinline_for_stack to keep it separate from
the other variables and prevent multiple copies of the same variable
to get inlined here.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/scsi/bfa/bfa_fcs_lport.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/bfa/bfa_fcs_lport.c b/drivers/scsi/bfa/bfa_fcs_lport.c
index 2df399c537c1..8c9d423129c0 100644
--- a/drivers/scsi/bfa/bfa_fcs_lport.c
+++ b/drivers/scsi/bfa/bfa_fcs_lport.c
@@ -2627,7 +2627,7 @@ bfa_fcs_fdmi_get_hbaattr(struct bfa_fcs_lport_fdmi_s *fdmi,
 
 }
 
-static void
+static noinline_for_stack void
 bfa_fcs_fdmi_get_portattr(struct bfa_fcs_lport_fdmi_s *fdmi,
 			  struct bfa_fcs_fdmi_port_attr_s *port_attr)
 {
-- 
2.39.5

Re: [PATCH] scsi: bfa: reduce kernel stack usage in bfa_fcs_lport_fdmi_build_portattr_block

[Martin K. Petersen]

Arnd,

> bfa_fcs_fdmi_get_portattr() gets inlined into multiple places and has
> two fairly large variables on the stack, to the point of causing a
> warning in some randconfig builds:

Applied to 7.2/scsi-staging, thanks!

-- 
Martin K. Petersen