On Tuesday 06 October 2009 18:20:43 Albert Herranz wrote:
> The DMA-API debugging facility complains about b43 mapping memory from
> stack for SDIO-based cards, as can be seen in the following two
> stack traces.
>
> Call Trace:
> [d2ef7c60] [c01c55f0] check_for_stack+0xf4/0x10c (unreliable)
> [d2ef7c80] [c01c6d10] debug_dma_map_sg+0xc4/0x134
> [d2ef7cb0] [c0281e10] sdhci_prepare_data+0x200/0x590
> [d2ef7ce0] [c0282288] sdhci_send_command+0xe8/0x320
> [d2ef7d00] [c02825e0] sdhci_request+0x120/0x1b4
> [d2ef7d20] [c0277ad4] mmc_wait_for_req+0x124/0x140
> [d2ef7d50] [c027c2f0] mmc_io_rw_extended+0x188/0x214
> [d2ef7e10] [c027d7c4] sdio_io_rw_ext_helper+0x104/0x224
> [d2ef7e40] [c0296000] ssb_sdio_block_read+0xac/0x110
> [d2ef7e60] [c0237f98] pio_rx_frame+0x1d0/0x43c
> [d2ef7eb0] [c0238244] b43_pio_rx+0x40/0x90
> [d2ef7ed0] [c0226124] b43_do_interrupt_thread+0x108/0x444
> [d2ef7f30] [c0226504] b43_sdio_interrupt_handler+0x58/0x74
> [d2ef7f40] [c0239110] b43_sdio_interrupt_dispatcher+0x4c/0x68
> [d2ef7f60] [c027e1ac] sdio_irq_thread+0xf8/0x284
> [d2ef7fb0] [c0054538] kthread+0x78/0x7c
> [d2ef7ff0] [c00124ec] kernel_thread+0x4c/0x68
>
> Call Trace:
> [d3335c20] [c01c55f0] check_for_stack+0xf4/0x10c (unreliable)
> [d3335c40] [c01c6d10] debug_dma_map_sg+0xc4/0x134
> [d3335c70] [c0281e14] sdhci_prepare_data+0x200/0x590
> [d3335ca0] [c028228c] sdhci_send_command+0xe8/0x320
> [d3335cc0] [c02825e4] sdhci_request+0x120/0x1b4
> [d3335ce0] [c0277ad8] mmc_wait_for_req+0x124/0x140
> [d3335d10] [c027c2f4] mmc_io_rw_extended+0x188/0x214
> [d3335dd0] [c027d86c] sdio_io_rw_ext_helper+0x1a8/0x224
> [d3335e00] [c0295ef4] ssb_sdio_block_write+0xac/0x110
> [d3335e20] [c0237a18] tx_write_4byte_queue+0x6c/0x138
> [d3335e40] [c0238610] pio_tx_frame+0x1c4/0x224
> [d3335ee0] [c0238718] b43_pio_tx+0xa8/0x1f4
> [d3335f00] [c0220380] b43_tx_work+0x4c/0xe0
> [d3335f20] [c004fa74] run_workqueue+0x120/0x1a4
> [d3335f70] [c004fb44] worker_thread+0x4c/0xb0
> [d3335fb0] [c0054538] kthread+0x78/0x7c
> [d3335ff0] [c00124ec] kernel_thread+0x4c/0x68
>
> Indeed, b43 currently allocates the PIO RX and TX header buffers
> from stack. The solution here is to use heap-allocated buffers instead.
>
> Signed-off-by: Albert Herranz <albert_herr...@yahoo.es>
> ---
> drivers/net/wireless/b43/b43.h | 9 ++++++++
> drivers/net/wireless/b43/pio.c | 42 +++++++++++++++++++++++++++------------
> 2 files changed, 38 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/net/wireless/b43/b43.h b/drivers/net/wireless/b43/b43.h
> index fa1549a..b09dda1 100644
> --- a/drivers/net/wireless/b43/b43.h
> +++ b/drivers/net/wireless/b43/b43.h
> @@ -550,6 +550,9 @@ struct b43_dma {
> struct b43_pio_txqueue;
> struct b43_pio_rxqueue;
>
> +struct b43_rxhdr_fw4;
> +struct b43_txhdr;
> +
> /* Data structures for PIO transmission, per 80211 core. */
> struct b43_pio {
> struct b43_pio_txqueue *tx_queue_AC_BK; /* Background */
> @@ -559,6 +562,12 @@ struct b43_pio {
> struct b43_pio_txqueue *tx_queue_mcast; /* Multicast */
>
> struct b43_pio_rxqueue *rx_queue;
> +
> + /*
> + * RX/TX header buffers used by the frame transmit functions.
> + */
> + struct b43_rxhdr_fw4 *rxhdr;
> + struct b43_txhdr *txhdr;
> };
Just embed it into struct b43_wl (surround it by #ifdef CONFIG_B43_PIO). No need
to kzalloc then and it saves some memory.
You also need to alloc 4 bytes for the tail buffer (that currently is on the
stack, too).
--
Greetings, Michael.
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