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| author | Hans Petter Selasky <hselasky@FreeBSD.org> | 2018-09-06 11:06:07 +0000 |
|---|---|---|
| committer | Hans Petter Selasky <hselasky@FreeBSD.org> | 2018-09-06 11:06:07 +0000 |
| commit | 2d32b0a3049c22f13062396101ba622686a39ec6 (patch) | |
| tree | d0930ca4dbeb3b70a1ae441e659585f62e8f22a2 /sys/dev | |
| parent | cc4f3d0ae2ee820dce2863d2ea1b901188e9fbdb (diff) | |
| download | src-2d32b0a3049c22f13062396101ba622686a39ec6.tar.gz src-2d32b0a3049c22f13062396101ba622686a39ec6.zip | |
Maximum number of mbuf frags is off-by-one for worst case scenario in mlx5en(4).
Inspecting the PRM no more than 0x3F data segments, DS, of size 16 bytes is
allowed.
Worst case scenario summary of DS usage:
Header is fixed: 2 DS
Maximum inlining: 98 => (98 - 2) / 16 = 6 DS
Remainder: 0x3F - 2 - 6 = 55 DS (mbuf frags)
Previously a value of 56 DS was used and this would work in the
normal case because not all inline data area was used up.
MFC after: 3 days
Approved by: re (marius)
Sponsored by: Mellanox Technologies
Notes
Notes:
svn path=/head/; revision=338489
Diffstat (limited to 'sys/dev')
| -rw-r--r-- | sys/dev/mlx5/mlx5_en/en.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/sys/dev/mlx5/mlx5_en/en.h b/sys/dev/mlx5/mlx5_en/en.h index f125313cd7b9..eff172b55cdc 100644 --- a/sys/dev/mlx5/mlx5_en/en.h +++ b/sys/dev/mlx5/mlx5_en/en.h @@ -123,7 +123,8 @@ #define MLX5E_MAX_TX_MBUF_SIZE 65536 /* bytes */ #define MLX5E_MAX_TX_MBUF_FRAGS \ ((MLX5_SEND_WQE_MAX_WQEBBS * MLX5_SEND_WQEBB_NUM_DS) - \ - (MLX5E_MAX_TX_HEADER / MLX5_SEND_WQE_DS)) /* units */ + (MLX5E_MAX_TX_HEADER / MLX5_SEND_WQE_DS) - \ + 1 /* the maximum value of the DS counter is 0x3F and not 0x40 */) /* units */ #define MLX5E_MAX_TX_INLINE \ (MLX5E_MAX_TX_HEADER - sizeof(struct mlx5e_tx_wqe) + \ sizeof(((struct mlx5e_tx_wqe *)0)->eth.inline_hdr_start)) /* bytes */ |