target/linux/mpc85xx/patches-4.4/200-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 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  35 ---
  36  drivers/spi/spi-fsl-espi.c | 34 ++++++++++++++++------------------
  37  drivers/spi/spi-fsl-lib.h  |  1 +
  38  2 files changed, 17 insertions(+), 18 deletions(-)
  39
  40 --- a/drivers/spi/spi-fsl-espi.c
  41 +++ b/drivers/spi/spi-fsl-espi.c
  42 @@ -332,17 +332,13 @@ static void fsl_espi_do_trans(struct spi
  43  static void fsl_espi_cmd_trans(struct spi_message *m,
  44                                 struct fsl_espi_transfer *trans, u8 *rx_buff)
  45  {
  46 +       struct spi_device *spi = m->spi;
  47 +       struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
  48         struct spi_transfer *t;
  49 -       u8 *local_buf;
  50 +       u8 *local_buf = mspi->local_buf;
  51         int i = 0;
  52         struct fsl_espi_transfer *espi_trans = trans;
  53
  54 -       local_buf = kzalloc(SPCOM_TRANLEN_MAX, GFP_KERNEL);
  55 -       if (!local_buf) {
  56 -               espi_trans->status = -ENOMEM;
  57 -               return;
  58 -       }
  59 -
  60         list_for_each_entry(t, &m->transfers, transfer_list) {
  61                 if (t->tx_buf) {
  62                         memcpy(local_buf + i, t->tx_buf, t->len);
  63 @@ -355,16 +351,17 @@ static void fsl_espi_cmd_trans(struct sp
  64         fsl_espi_do_trans(m, espi_trans);
  65
  66         espi_trans->actual_length = espi_trans->len;
  67 -       kfree(local_buf);
  68  }
  69
  70  static void fsl_espi_rw_trans(struct spi_message *m,
  71                                 struct fsl_espi_transfer *trans, u8 *rx_buff)
  72  {
  73 +       struct spi_device *spi = m->spi;
  74 +       struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
  75         struct fsl_espi_transfer *espi_trans = trans;
  76         unsigned int total_len = espi_trans->len;
  77         struct spi_transfer *t;
  78 -       u8 *local_buf;
  79 +       u8 *local_buf = mspi->local_buf;
  80         u8 *rx_buf = rx_buff;
  81         unsigned int trans_len;
  82         unsigned int addr;
  83 @@ -373,12 +370,6 @@ static void fsl_espi_rw_trans(struct spi
  84         unsigned int pos;
  85         int i, 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 < total_len; pos += trans_len, loop++) {
  94                 trans_len = total_len - pos;
  95
  96 @@ -424,8 +415,6 @@ static void fsl_espi_rw_trans(struct spi
  97                 else
  98                         espi_trans->actual_length += espi_trans->len;
  99         }
 100 -
 101 -       kfree(local_buf);
 102  }
 103
 104  static int fsl_espi_do_one_msg(struct spi_master *master,
 105 @@ -673,6 +662,12 @@ static struct spi_master * fsl_espi_prob
 106
 107         mpc8xxx_spi = spi_master_get_devdata(master);
 108
 109 +       mpc8xxx_spi->local_buf = devm_kzalloc(dev, SPCOM_TRANLEN_MAX, GFP_KERNEL);
 110 +       if (!mpc8xxx_spi->local_buf) {
 111 +               ret = -ENOMEM;
 112 +               goto err_probe;
 113 +       }
 114 +
 115         mpc8xxx_spi->reg_base = devm_ioremap_resource(dev, mem);
 116         if (IS_ERR(mpc8xxx_spi->reg_base)) {
 117                 ret = PTR_ERR(mpc8xxx_spi->reg_base);
 118 --- a/drivers/spi/spi-fsl-lib.h
 119 +++ b/drivers/spi/spi-fsl-lib.h
 120 @@ -30,6 +30,7 @@ struct mpc8xxx_spi {
 121         void *rx;
 122  #if IS_ENABLED(CONFIG_SPI_FSL_ESPI)
 123         int len;
 124 +       u8 *local_buf;
 125  #endif
 126
 127         int subblock;