target/linux/mpc85xx/patches-3.10/210-spi-fsl-espi-preallocate-local-buffer.patch

   1 From: Gabor Juhos <juhosg@openwrt.org>
   2 Subject: spi-fsl-espi: avoid frequent high order allocations
   3
   4 The driver allocates 64KiB of memory fro a local buffer before
   5 each transfer and releases that afterwards. When the memory is
   6 fragmented this allocation often fails and causes a warning like
   7 this:
   8
   9   kworker/u2:2: page allocation failure: order:4, mode:0x10c0d0
  10   CPU: 0 PID: 7011 Comm: kworker/u2:2 Not tainted 3.10.24 #1
  11   Workqueue: ffe07000.spi mpc8xxx_spi_work
  12   Call Trace:
  13   [c1c6dcf0] [c0006914] show_stack+0x50/0x170 (unreliable)
  14   [c1c6dd30] [c0259858] dump_stack+0x24/0x34
  15   [c1c6dd40] [c00672e8] warn_alloc_failed+0x120/0x13c
  16   [c1c6dd90] [c0069920] __alloc_pages_nodemask+0x574/0x5c8
  17   [c1c6de20] [c0069990] __get_free_pages+0x1c/0x4c
  18   [c1c6de30] [c0185174] fsl_espi_do_one_msg+0x128/0x2a0
  19   [c1c6de90] [c0184290] mpc8xxx_spi_work+0x50/0x7c
  20   [c1c6dea0] [c0037af8] process_one_work+0x208/0x30c
  21   [c1c6dec0] [c00387a0] worker_thread+0x20c/0x308
  22   [c1c6def0] [c003de60] kthread+0xa4/0xa8
  23   [c1c6df40] [c000c4bc] ret_from_kernel_thread+0x5c/0x64
  24
  25   m25p80 spi0.0: error -12 reading SR
  26   end_request: I/O error, dev mtdblock3, sector 680
  27   SQUASHFS error: squashfs_read_data failed to read block 0x54a4a
  28   SQUASHFS error: Unable to read data cache entry [54a4a]
  29
  30 Preallocate the buffer from the probe routine to avoid
  31 this.
  32
  33 Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
  34 ---
  35 --- a/drivers/spi/spi-fsl-espi.c
  36 +++ b/drivers/spi/spi-fsl-espi.c
  37 @@ -338,17 +338,13 @@ static void fsl_espi_do_trans(struct spi
  38  static void fsl_espi_cmd_trans(struct spi_message *m,
  39                                 struct fsl_espi_transfer *trans, u8 *rx_buff)
  40  {
  41 +       struct spi_device *spi = m->spi;
  42 +       struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
  43         struct spi_transfer *t;
  44 -       u8 *local_buf;
  45 +       u8 *local_buf = mspi->local_buf;
  46         int i = 0;
  47         struct fsl_espi_transfer *espi_trans = trans;
  48
  49 -       local_buf = kzalloc(SPCOM_TRANLEN_MAX, GFP_KERNEL);
  50 -       if (!local_buf) {
  51 -               espi_trans->status = -ENOMEM;
  52 -               return;
  53 -       }
  54 -
  55         list_for_each_entry(t, &m->transfers, transfer_list) {
  56                 if (t->tx_buf) {
  57                         memcpy(local_buf + i, t->tx_buf, t->len);
  58 @@ -361,28 +357,23 @@ static void fsl_espi_cmd_trans(struct sp
  59         fsl_espi_do_trans(m, espi_trans);
  60
  61         espi_trans->actual_length = espi_trans->len;
  62 -       kfree(local_buf);
  63  }
  64
  65  static void fsl_espi_rw_trans(struct spi_message *m,
  66                                 struct fsl_espi_transfer *trans, u8 *rx_buff)
  67  {
  68 +       struct spi_device *spi = m->spi;
  69 +       struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
  70         struct fsl_espi_transfer *espi_trans = trans;
  71         unsigned int n_tx = espi_trans->n_tx;
  72         unsigned int n_rx = espi_trans->n_rx;
  73         struct spi_transfer *t;
  74 -       u8 *local_buf;
  75 +       u8 *local_buf = mspi->local_buf;
  76         u8 *rx_buf = rx_buff;
  77         unsigned int trans_len;
  78         unsigned int addr;
  79         int i, pos, loop;
  80
  81 -       local_buf = kzalloc(SPCOM_TRANLEN_MAX, GFP_KERNEL);
  82 -       if (!local_buf) {
  83 -               espi_trans->status = -ENOMEM;
  84 -               return;
  85 -       }
  86 -
  87         for (pos = 0, loop = 0; pos < n_rx; pos += trans_len, loop++) {
  88                 trans_len = n_rx - pos;
  89                 if (trans_len > SPCOM_TRANLEN_MAX - n_tx)
  90 @@ -416,8 +407,6 @@ static void fsl_espi_rw_trans(struct spi
  91                 else
  92                         espi_trans->actual_length += espi_trans->len;
  93         }
  94 -
  95 -       kfree(local_buf);
  96  }
  97
  98  static void fsl_espi_do_one_msg(struct spi_message *m)
  99 @@ -585,6 +574,7 @@ static irqreturn_t fsl_espi_irq(s32 irq,
 100  static void fsl_espi_remove(struct mpc8xxx_spi *mspi)
 101  {
 102         iounmap(mspi->reg_base);
 103 +       kfree(mspi->local_buf);
 104  }
 105
 106  static struct spi_master * fsl_espi_probe(struct device *dev,
 107 @@ -615,10 +605,16 @@ static struct spi_master * fsl_espi_prob
 108         mpc8xxx_spi->spi_do_one_msg = fsl_espi_do_one_msg;
 109         mpc8xxx_spi->spi_remove = fsl_espi_remove;
 110
 111 +       mpc8xxx_spi->local_buf = kzalloc(SPCOM_TRANLEN_MAX, GFP_KERNEL);
 112 +       if (!mpc8xxx_spi->local_buf) {
 113 +               ret = -ENOMEM;
 114 +               goto err_probe;
 115 +       }
 116 +
 117         mpc8xxx_spi->reg_base = ioremap(mem->start, resource_size(mem));
 118         if (!mpc8xxx_spi->reg_base) {
 119                 ret = -ENOMEM;
 120 -               goto err_probe;
 121 +               goto free_buf;
 122         }
 123
 124         reg_base = mpc8xxx_spi->reg_base;
 125 @@ -661,6 +657,8 @@ unreg_master:
 126         free_irq(mpc8xxx_spi->irq, mpc8xxx_spi);
 127  free_irq:
 128         iounmap(mpc8xxx_spi->reg_base);
 129 +free_buf:
 130 +       kfree(mpc8xxx_spi->local_buf);
 131  err_probe:
 132         spi_master_put(master);
 133  err:
 134 --- a/drivers/spi/spi-fsl-lib.h
 135 +++ b/drivers/spi/spi-fsl-lib.h
 136 @@ -30,6 +30,7 @@ struct mpc8xxx_spi {
 137         void *rx;
 138  #ifdef CONFIG_SPI_FSL_ESPI
 139         int len;
 140 +       u8 *local_buf;
 141  #endif
 142
 143         int subblock;