bz204119.patch

   1 From dccc96abfb21dc19d69e707c38c8ba439bba7160 Mon Sep 17 00:00:00 2001
   2 From: Bart Van Assche <bvanassche@acm.org>
   3 Date: Thu, 1 Aug 2019 15:38:14 -0700
   4 Subject: scsi: core: Reduce memory required for SCSI logging
   5
   6 The data structure used for log messages is so large that it can cause a
   7 boot failure. Since allocations from that data structure can fail anyway,
   8 use kmalloc() / kfree() instead of that data structure.
   9
  10 See also https://bugzilla.kernel.org/show_bug.cgi?id=204119.
  11 See also commit ded85c193a39 ("scsi: Implement per-cpu logging buffer") # v4.0.
  12
  13 Reported-by: Jan Palus <jpalus@fastmail.com>
  14 Cc: Christoph Hellwig <hch@lst.de>
  15 Cc: Hannes Reinecke <hare@suse.com>
  16 Cc: Johannes Thumshirn <jthumshirn@suse.de>
  17 Cc: Ming Lei <ming.lei@redhat.com>
  18 Cc: Jan Palus <jpalus@fastmail.com>
  19 Signed-off-by: Bart Van Assche <bvanassche@acm.org>
  20 Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
  21 ---
  22  drivers/scsi/scsi_logging.c | 48 +++------------------------------------------
  23  include/scsi/scsi_dbg.h     |  2 --
  24  2 files changed, 3 insertions(+), 47 deletions(-)
  25
  26 diff --git a/drivers/scsi/scsi_logging.c b/drivers/scsi/scsi_logging.c
  27 index 39b8cc4574b4..c6ed0b12e807 100644
  28 --- a/drivers/scsi/scsi_logging.c
  29 +++ b/drivers/scsi/scsi_logging.c
  30 @@ -15,57 +15,15 @@
  31  #include <scsi/scsi_eh.h>
  32  #include <scsi/scsi_dbg.h>
  33
  34 -#define SCSI_LOG_SPOOLSIZE 4096
  35 -
  36 -#if (SCSI_LOG_SPOOLSIZE / SCSI_LOG_BUFSIZE) > BITS_PER_LONG
  37 -#warning SCSI logging bitmask too large
  38 -#endif
  39 -
  40 -struct scsi_log_buf {
  41 -       char buffer[SCSI_LOG_SPOOLSIZE];
  42 -       unsigned long map;
  43 -};
  44 -
  45 -static DEFINE_PER_CPU(struct scsi_log_buf, scsi_format_log);
  46 -
  47  static char *scsi_log_reserve_buffer(size_t *len)
  48  {
  49 -       struct scsi_log_buf *buf;
  50 -       unsigned long map_bits = sizeof(buf->buffer) / SCSI_LOG_BUFSIZE;
  51 -       unsigned long idx = 0;
  52 -
  53 -       preempt_disable();
  54 -       buf = this_cpu_ptr(&scsi_format_log);
  55 -       idx = find_first_zero_bit(&buf->map, map_bits);
  56 -       if (likely(idx < map_bits)) {
  57 -               while (test_and_set_bit(idx, &buf->map)) {
  58 -                       idx = find_next_zero_bit(&buf->map, map_bits, idx);
  59 -                       if (idx >= map_bits)
  60 -                               break;
  61 -               }
  62 -       }
  63 -       if (WARN_ON(idx >= map_bits)) {
  64 -               preempt_enable();
  65 -               return NULL;
  66 -       }
  67 -       *len = SCSI_LOG_BUFSIZE;
  68 -       return buf->buffer + idx * SCSI_LOG_BUFSIZE;
  69 +       *len = 128;
  70 +       return kmalloc(*len, GFP_ATOMIC);
  71  }
  72
  73  static void scsi_log_release_buffer(char *bufptr)
  74  {
  75 -       struct scsi_log_buf *buf;
  76 -       unsigned long idx;
  77 -       int ret;
  78 -
  79 -       buf = this_cpu_ptr(&scsi_format_log);
  80 -       if (bufptr >= buf->buffer &&
  81 -           bufptr < buf->buffer + SCSI_LOG_SPOOLSIZE) {
  82 -               idx = (bufptr - buf->buffer) / SCSI_LOG_BUFSIZE;
  83 -               ret = test_and_clear_bit(idx, &buf->map);
  84 -               WARN_ON(!ret);
  85 -       }
  86 -       preempt_enable();
  87 +       kfree(bufptr);
  88  }
  89
  90  static inline const char *scmd_name(const struct scsi_cmnd *scmd)
  91 diff --git a/include/scsi/scsi_dbg.h b/include/scsi/scsi_dbg.h
  92 index e03bd9d41fa8..7b196d234626 100644
  93 --- a/include/scsi/scsi_dbg.h
  94 +++ b/include/scsi/scsi_dbg.h
  95 @@ -6,8 +6,6 @@ struct scsi_cmnd;
  96  struct scsi_device;
  97  struct scsi_sense_hdr;
  98
  99 -#define SCSI_LOG_BUFSIZE 128
 100 -
 101  extern void scsi_print_command(struct scsi_cmnd *);
 102  extern size_t __scsi_format_command(char *, size_t,
 103                                    const unsigned char *, size_t);
 104 --
 105 cgit 1.2-0.3.lf.el7
 106