target/linux/mpc85xx/patches-3.14/210-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  drivers/spi/spi-fsl-espi.c | 34 ++++++++++++++++------------------
  36  drivers/spi/spi-fsl-lib.h  |  1 +
  37  2 files changed, 17 insertions(+), 18 deletions(-)
  38
  39 diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c
  40 index 428dc7a..5207176 100644
  41 --- a/drivers/spi/spi-fsl-espi.c
  42 +++ b/drivers/spi/spi-fsl-espi.c
  43 @@ -334,17 +334,13 @@ static void fsl_espi_do_trans(struct spi_message *m,
  44  static void fsl_espi_cmd_trans(struct spi_message *m,
  45                                 struct fsl_espi_transfer *trans, u8 *rx_buff)
  46  {
  47 +       struct spi_device *spi = m->spi;
  48 +       struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
  49         struct spi_transfer *t;
  50 -       u8 *local_buf;
  51 +       u8 *local_buf = mspi->local_buf;
  52         int i = 0;
  53         struct fsl_espi_transfer *espi_trans = trans;
  54
  55 -       local_buf = kzalloc(SPCOM_TRANLEN_MAX, GFP_KERNEL);
  56 -       if (!local_buf) {
  57 -               espi_trans->status = -ENOMEM;
  58 -               return;
  59 -       }
  60 -
  61         list_for_each_entry(t, &m->transfers, transfer_list) {
  62                 if (t->tx_buf) {
  63                         memcpy(local_buf + i, t->tx_buf, t->len);
  64 @@ -357,28 +353,23 @@ static void fsl_espi_cmd_trans(struct spi_message *m,
  65         fsl_espi_do_trans(m, espi_trans);
  66
  67         espi_trans->actual_length = espi_trans->len;
  68 -       kfree(local_buf);
  69  }
  70
  71  static void fsl_espi_rw_trans(struct spi_message *m,
  72                                 struct fsl_espi_transfer *trans, u8 *rx_buff)
  73  {
  74 +       struct spi_device *spi = m->spi;
  75 +       struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
  76         struct fsl_espi_transfer *espi_trans = trans;
  77         unsigned int n_tx = espi_trans->n_tx;
  78         unsigned int n_rx = espi_trans->n_rx;
  79         struct spi_transfer *t;
  80 -       u8 *local_buf;
  81 +       u8 *local_buf = mspi->local_buf;
  82         u8 *rx_buf = rx_buff;
  83         unsigned int trans_len;
  84         unsigned int addr;
  85         int i, pos, loop;
  86
  87 -       local_buf = kzalloc(SPCOM_TRANLEN_MAX, GFP_KERNEL);
  88 -       if (!local_buf) {
  89 -               espi_trans->status = -ENOMEM;
  90 -               return;
  91 -       }
  92 -
  93         for (pos = 0, loop = 0; pos < n_rx; pos += trans_len, loop++) {
  94                 trans_len = n_rx - pos;
  95                 if (trans_len > SPCOM_TRANLEN_MAX - n_tx)
  96 @@ -412,8 +403,6 @@ static void fsl_espi_rw_trans(struct spi_message *m,
  97                 else
  98                         espi_trans->actual_length += espi_trans->len;
  99         }
 100 -
 101 -       kfree(local_buf);
 102  }
 103
 104  static void fsl_espi_do_one_msg(struct spi_message *m)
 105 @@ -581,6 +570,7 @@ static irqreturn_t fsl_espi_irq(s32 irq, void *context_data)
 106  static void fsl_espi_remove(struct mpc8xxx_spi *mspi)
 107  {
 108         iounmap(mspi->reg_base);
 109 +       kfree(mspi->local_buf);
 110  }
 111
 112  static struct spi_master * fsl_espi_probe(struct device *dev,
 113 @@ -612,10 +602,16 @@ static struct spi_master * fsl_espi_probe(struct device *dev,
 114         mpc8xxx_spi->spi_do_one_msg = fsl_espi_do_one_msg;
 115         mpc8xxx_spi->spi_remove = fsl_espi_remove;
 116
 117 +       mpc8xxx_spi->local_buf = kzalloc(SPCOM_TRANLEN_MAX, GFP_KERNEL);
 118 +       if (!mpc8xxx_spi->local_buf) {
 119 +               ret = -ENOMEM;
 120 +               goto err_probe;
 121 +       }
 122 +
 123         mpc8xxx_spi->reg_base = ioremap(mem->start, resource_size(mem));
 124         if (!mpc8xxx_spi->reg_base) {
 125                 ret = -ENOMEM;
 126 -               goto err_probe;
 127 +               goto free_buf;
 128         }
 129
 130         reg_base = mpc8xxx_spi->reg_base;
 131 @@ -658,6 +654,8 @@ unreg_master:
 132         free_irq(mpc8xxx_spi->irq, mpc8xxx_spi);
 133  free_irq:
 134         iounmap(mpc8xxx_spi->reg_base);
 135 +free_buf:
 136 +       kfree(mpc8xxx_spi->local_buf);
 137  err_probe:
 138         spi_master_put(master);
 139  err:
 140 diff --git a/drivers/spi/spi-fsl-lib.h b/drivers/spi/spi-fsl-lib.h
 141 index 52db693..8dda68b 100644
 142 --- a/drivers/spi/spi-fsl-lib.h
 143 +++ b/drivers/spi/spi-fsl-lib.h
 144 @@ -30,6 +30,7 @@ struct mpc8xxx_spi {
 145         void *rx;
 146  #ifdef CONFIG_SPI_FSL_ESPI
 147         int len;
 148 +       u8 *local_buf;
 149  #endif
 150
 151         int subblock;
 152 --
 153 2.1.3
 154