diff mbox series

[net-next,v2,08/14] ice: use stack variable for virtchnl_supported_rxdids

Message ID 20241113185431.1289708-9-anthony.l.nguyen@intel.com (mailing list archive)
State New
Delegated to: Netdev Maintainers
Headers show
Series Intel Wired LAN Driver Updates 2024-11-05 (ice, ixgbe, igc. igb, igbvf, e1000) | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 3 this patch: 3
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 5 of 5 maintainers
netdev/build_clang success Errors and warnings before: 3 this patch: 3
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 4 this patch: 4
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 35 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 140 this patch: 140
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-11-14--03-00 (tests: 782)

Commit Message

Tony Nguyen Nov. 13, 2024, 6:54 p.m. UTC 
From: Jacob Keller <jacob.e.keller@intel.com>

The ice_vc_query_rxdid() function allocates memory to store the
virtchnl_supported_rxdids structure used to communicate the bitmap of
supported RXDIDs to a VF.

This structure is only 8 bytes in size. The function must hold the
allocated length on the stack as well as the pointer to the structure which
itself is 8 bytes. Allocating this storage on the heap adds unnecessary
overhead including a potential error path that must be handled in case
kzalloc fails. Because this structure is so small, we're not saving stack
space. Additionally, because we must ensure that we free the allocated
memory, the return value from ice_vc_send_msg_to_vf() must also be saved in
the stack ret variable. Depending on compiler optimization, this means
allocating the 8-byte structure is requiring up to 16-bytes of stack
memory!

Simplify this function to keep the rxdid variable on the stack, saving
memory and removing a potential failure exit path from this function.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
---
 drivers/net/ethernet/intel/ice/ice_virtchnl.c | 20 ++++---------------
 1 file changed, 4 insertions(+), 16 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/intel/ice/ice_virtchnl.c b/drivers/net/ethernet/intel/ice/ice_virtchnl.c
index bc9fadaccad0..f445e33b2028 100644
--- a/drivers/net/ethernet/intel/ice/ice_virtchnl.c
+++ b/drivers/net/ethernet/intel/ice/ice_virtchnl.c
@@ -3031,10 +3031,8 @@  static int ice_vc_set_rss_hena(struct ice_vf *vf, u8 *msg)
 static int ice_vc_query_rxdid(struct ice_vf *vf)
 {
 	enum virtchnl_status_code v_ret = VIRTCHNL_STATUS_SUCCESS;
-	struct virtchnl_supported_rxdids *rxdid = NULL;
+	struct virtchnl_supported_rxdids rxdid = {};
 	struct ice_pf *pf = vf->pf;
-	int len = 0;
-	int ret;
 
 	if (!test_bit(ICE_VF_STATE_ACTIVE, vf->vf_states)) {
 		v_ret = VIRTCHNL_STATUS_ERR_PARAM;
@@ -3046,21 +3044,11 @@  static int ice_vc_query_rxdid(struct ice_vf *vf)
 		goto err;
 	}
 
-	len = sizeof(struct virtchnl_supported_rxdids);
-	rxdid = kzalloc(len, GFP_KERNEL);
-	if (!rxdid) {
-		v_ret = VIRTCHNL_STATUS_ERR_NO_MEMORY;
-		len = 0;
-		goto err;
-	}
-
-	rxdid->supported_rxdids = pf->supported_rxdids;
+	rxdid.supported_rxdids = pf->supported_rxdids;
 
 err:
-	ret = ice_vc_send_msg_to_vf(vf, VIRTCHNL_OP_GET_SUPPORTED_RXDIDS,
-				    v_ret, (u8 *)rxdid, len);
-	kfree(rxdid);
-	return ret;
+	return ice_vc_send_msg_to_vf(vf, VIRTCHNL_OP_GET_SUPPORTED_RXDIDS,
+				     v_ret, (u8 *)&rxdid, sizeof(rxdid));
 }
 
 /**