diff mbox series

[net,1/3] ice: fix receive buffer size miscalculation

Message ID 20230821171633.2203505-2-anthony.l.nguyen@intel.com (mailing list archive)
State Accepted
Commit 10083aef784031fa9f06c19a1b182e6fad5338d9
Delegated to: Netdev Maintainers
Headers show
Series Intel Wired LAN Driver Updates 2023-08-21 (ice) | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1328 this patch: 1328
netdev/cc_maintainers success CCed 5 of 5 maintainers
netdev/build_clang success Errors and warnings before: 1351 this patch: 1351
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 Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 1351 this patch: 1351
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 9 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Tony Nguyen Aug. 21, 2023, 5:16 p.m. UTC 
From: Jesse Brandeburg <jesse.brandeburg@intel.com>

The driver is misconfiguring the hardware for some values of MTU such that
it could use multiple descriptors to receive a packet when it could have
simply used one.

Change the driver to use a round-up instead of the result of a shift, as
the shift can truncate the lower bits of the size, and result in the
problem noted above. It also aligns this driver with similar code in i40e.

The insidiousness of this problem is that everything works with the wrong
size, it's just not working as well as it could, as some MTU sizes end up
using two or more descriptors, and there is no way to tell that is
happening without looking at ice_trace or a bus analyzer.

Fixes: efc2214b6047 ("ice: Add support for XDP")
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
---
 drivers/net/ethernet/intel/ice/ice_base.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/intel/ice/ice_base.c b/drivers/net/ethernet/intel/ice/ice_base.c
index b678bdf96f3a..074bf9403cd1 100644
--- a/drivers/net/ethernet/intel/ice/ice_base.c
+++ b/drivers/net/ethernet/intel/ice/ice_base.c
@@ -435,7 +435,8 @@  static int ice_setup_rx_ctx(struct ice_rx_ring *ring)
 	/* Receive Packet Data Buffer Size.
 	 * The Packet Data Buffer Size is defined in 128 byte units.
 	 */
-	rlan_ctx.dbuf = ring->rx_buf_len >> ICE_RLAN_CTX_DBUF_S;
+	rlan_ctx.dbuf = DIV_ROUND_UP(ring->rx_buf_len,
+				     BIT_ULL(ICE_RLAN_CTX_DBUF_S));
 
 	/* use 32 byte descriptors */
 	rlan_ctx.dsize = 1;