Revision bce0b6c51ac76fc0e763262a6c2a9d05e486f0d8 authored by Steven Rostedt (Red Hat) on 21 August 2014, 03:57:04 UTC, committed by Steven Rostedt on 22 August 2014, 19:24:12 UTC
Now that a ftrace_hash can be shared by multiple ftrace_ops, they can dec the rec->flags by more than once (one per those that share the ftrace_hash). This means that the tramp_hash may not have a hash item when it was added. For example, if two ftrace_ops share a hash for a ftrace record, and the first ops has a trampoline, when it adds itself it will set the rec->flags TRAMP flag and increments its nr_trampolines counter. When the second ops is added, it must clear that tramp flag but also decrement the other ops that shares its hash. As the update to the function callbacks has not yet been performed, the other ops will not have the tramp hash set yet and it can not be used to know to decrement its nr_trampolines. Luckily, the tramp_hash does not need to be used. As the ftrace_mutex is held, a ops with a trampoline to a record during an update of another ops that shares the record will have its func_hash pointing to it. Since a trampoline can only be set for a record if only one ops is attached to it, we can just check if the record has a trampoline (the FTRACE_FL_TRAMP flag is set) and then find the ops that has this record in its hashes. Also added some output to help debug when things go wrong. Cc: stable@vger.kernel.org # 3.16+ (apply after 3.17-rc4 is out) Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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scsi_eh.h
#ifndef _SCSI_SCSI_EH_H
#define _SCSI_SCSI_EH_H
#include <linux/scatterlist.h>
#include <scsi/scsi_cmnd.h>
struct scsi_device;
struct Scsi_Host;
/*
* This is a slightly modified SCSI sense "descriptor" format header.
* The addition is to allow the 0x70 and 0x71 response codes. The idea
* is to place the salient data from either "fixed" or "descriptor" sense
* format into one structure to ease application processing.
*
* The original sense buffer should be kept around for those cases
* in which more information is required (e.g. the LBA of a MEDIUM ERROR).
*/
struct scsi_sense_hdr { /* See SPC-3 section 4.5 */
u8 response_code; /* permit: 0x0, 0x70, 0x71, 0x72, 0x73 */
u8 sense_key;
u8 asc;
u8 ascq;
u8 byte4;
u8 byte5;
u8 byte6;
u8 additional_length; /* always 0 for fixed sense format */
};
static inline int scsi_sense_valid(struct scsi_sense_hdr *sshdr)
{
if (!sshdr)
return 0;
return (sshdr->response_code & 0x70) == 0x70;
}
extern void scsi_eh_finish_cmd(struct scsi_cmnd *scmd,
struct list_head *done_q);
extern void scsi_eh_flush_done_q(struct list_head *done_q);
extern void scsi_report_bus_reset(struct Scsi_Host *, int);
extern void scsi_report_device_reset(struct Scsi_Host *, int, int);
extern int scsi_block_when_processing_errors(struct scsi_device *);
extern int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
struct scsi_sense_hdr *sshdr);
extern int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
struct scsi_sense_hdr *sshdr);
static inline int scsi_sense_is_deferred(struct scsi_sense_hdr *sshdr)
{
return ((sshdr->response_code >= 0x70) && (sshdr->response_code & 1));
}
extern const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
int desc_type);
extern int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
u64 * info_out);
extern void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq);
/*
* Reset request from external source
*/
#define SCSI_TRY_RESET_DEVICE 1
#define SCSI_TRY_RESET_BUS 2
#define SCSI_TRY_RESET_HOST 3
#define SCSI_TRY_RESET_TARGET 4
extern int scsi_reset_provider(struct scsi_device *, int);
struct scsi_eh_save {
/* saved state */
int result;
enum dma_data_direction data_direction;
unsigned underflow;
unsigned char cmd_len;
unsigned char prot_op;
unsigned char *cmnd;
struct scsi_data_buffer sdb;
struct request *next_rq;
/* new command support */
unsigned char eh_cmnd[BLK_MAX_CDB];
struct scatterlist sense_sgl;
};
extern void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd,
struct scsi_eh_save *ses, unsigned char *cmnd,
int cmnd_size, unsigned sense_bytes);
extern void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd,
struct scsi_eh_save *ses);
#endif /* _SCSI_SCSI_EH_H */
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