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scsi: core: Reduce memory required for SCSI logging

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The data structure used for log messages is so large that it can cause a
boot failure. Since allocations from that data structure can fail anyway,
use kmalloc() / kfree() instead of that data structure.

See also https://bugzilla.kernel.org/show_bug.cgi?id=204119.
See also commit ded85c193a ("scsi: Implement per-cpu logging buffer") # v4.0.

Reported-by: Jan Palus <jpalus@fastmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Jan Palus <jpalus@fastmail.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Bart Van Assche 2019-08-01 15:38:14 -07:00 committed by Martin K. Petersen
parent 94ef80a5f0
commit dccc96abfb
2 changed files with 3 additions and 47 deletions
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48
drivers/scsi/scsi_logging.c
View File

@ -15,57 +15,15 @@
#include <scsi/scsi_eh.h>
#include <scsi/scsi_dbg.h>
#define SCSI_LOG_SPOOLSIZE 4096
#if (SCSI_LOG_SPOOLSIZE / SCSI_LOG_BUFSIZE) > BITS_PER_LONG
#warning SCSI logging bitmask too large
#endif
struct scsi_log_buf {
char buffer[SCSI_LOG_SPOOLSIZE];
unsigned long map;
};
static DEFINE_PER_CPU(struct scsi_log_buf, scsi_format_log);
static char *scsi_log_reserve_buffer(size_t *len)
{
struct scsi_log_buf *buf;
unsigned long map_bits = sizeof(buf->buffer) / SCSI_LOG_BUFSIZE;
unsigned long idx = 0;
preempt_disable();
buf = this_cpu_ptr(&scsi_format_log);
idx = find_first_zero_bit(&buf->map, map_bits);
if (likely(idx < map_bits)) {
while (test_and_set_bit(idx, &buf->map)) {
idx = find_next_zero_bit(&buf->map, map_bits, idx);
if (idx >= map_bits)
break;
}
}
if (WARN_ON(idx >= map_bits)) {
preempt_enable();
return NULL;
}
*len = SCSI_LOG_BUFSIZE;
return buf->buffer + idx * SCSI_LOG_BUFSIZE;
*len = 128;
return kmalloc(*len, GFP_ATOMIC);
}
static void scsi_log_release_buffer(char *bufptr)
{
struct scsi_log_buf *buf;
unsigned long idx;
int ret;
buf = this_cpu_ptr(&scsi_format_log);
if (bufptr >= buf->buffer &&
bufptr < buf->buffer + SCSI_LOG_SPOOLSIZE) {
idx = (bufptr - buf->buffer) / SCSI_LOG_BUFSIZE;
ret = test_and_clear_bit(idx, &buf->map);
WARN_ON(!ret);
}
preempt_enable();
kfree(bufptr);
}
static inline const char *scmd_name(const struct scsi_cmnd *scmd)

2
include/scsi/scsi_dbg.h
View File

@ -6,8 +6,6 @@ struct scsi_cmnd;
struct scsi_device;
struct scsi_sense_hdr;
#define SCSI_LOG_BUFSIZE 128
extern void scsi_print_command(struct scsi_cmnd *);
extern size_t __scsi_format_command(char *, size_t,
const unsigned char *, size_t);