Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 444 insertions, 0 deletions

diff --git a/drivers/scsi/constants.c b/drivers/scsi/constants.c
new file mode 100644
index 000000000..340785536
--- /dev/null
+++ b/drivers/scsi/constants.c
@@ -0,0 +1,444 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ASCII values for a number of symbolic constants, printing functions,
+ * etc.
+ * Additions for SCSI 2 and Linux 2.2.x by D. Gilbert (990422)
+ * Additions for SCSI 3+ (SPC-3 T10/1416-D Rev 07 3 May 2002)
+ *   by D. Gilbert and aeb (20020609)
+ * Updated to SPC-4 T10/1713-D Rev 36g, D. Gilbert 20130701
+ */
+
+#include <linux/blkdev.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_dbg.h>
+
+/* Commands with service actions that change the command name */
+#define THIRD_PARTY_COPY_OUT 0x83
+#define THIRD_PARTY_COPY_IN 0x84
+
+struct sa_name_list {
+	int opcode;
+	const struct value_name_pair *arr;
+	int arr_sz;
+};
+
+struct value_name_pair {
+	int value;
+	const char * name;
+};
+
+static const char * cdb_byte0_names[] = {
+/* 00-03 */ "Test Unit Ready", "Rezero Unit/Rewind", NULL, "Request Sense",
+/* 04-07 */ "Format Unit/Medium", "Read Block Limits", NULL,
+	    "Reassign Blocks",
+/* 08-0d */ "Read(6)", NULL, "Write(6)", "Seek(6)", NULL, NULL,
+/* 0e-12 */ NULL, "Read Reverse", "Write Filemarks", "Space", "Inquiry",
+/* 13-16 */ "Verify(6)", "Recover Buffered Data", "Mode Select(6)",
+	    "Reserve(6)",
+/* 17-1a */ "Release(6)", "Copy", "Erase", "Mode Sense(6)",
+/* 1b-1d */ "Start/Stop Unit", "Receive Diagnostic", "Send Diagnostic",
+/* 1e-1f */ "Prevent/Allow Medium Removal", NULL,
+/* 20-22 */  NULL, NULL, NULL,
+/* 23-28 */ "Read Format Capacities", "Set Window",
+	    "Read Capacity(10)", NULL, NULL, "Read(10)",
+/* 29-2d */ "Read Generation", "Write(10)", "Seek(10)", "Erase(10)",
+            "Read updated block",
+/* 2e-31 */ "Write Verify(10)", "Verify(10)", "Search High", "Search Equal",
+/* 32-34 */ "Search Low", "Set Limits", "Prefetch/Read Position",
+/* 35-37 */ "Synchronize Cache(10)", "Lock/Unlock Cache(10)",
+	    "Read Defect Data(10)",
+/* 38-3c */ "Medium Scan", "Compare", "Copy Verify", "Write Buffer",
+	    "Read Buffer",
+/* 3d-3f */ "Update Block", "Read Long(10)",  "Write Long(10)",
+/* 40-41 */ "Change Definition", "Write Same(10)",
+/* 42-48 */ "Unmap/Read sub-channel", "Read TOC/PMA/ATIP",
+	    "Read density support", "Play audio(10)", "Get configuration",
+	    "Play audio msf", "Sanitize/Play audio track/index",
+/* 49-4f */ "Play track relative(10)", "Get event status notification",
+            "Pause/resume", "Log Select", "Log Sense", "Stop play/scan",
+            NULL,
+/* 50-55 */ "Xdwrite", "Xpwrite, Read disk info", "Xdread, Read track info",
+            "Reserve track", "Send OPC info", "Mode Select(10)",
+/* 56-5b */ "Reserve(10)", "Release(10)", "Repair track", "Read master cue",
+            "Mode Sense(10)", "Close track/session",
+/* 5c-5f */ "Read buffer capacity", "Send cue sheet", "Persistent reserve in",
+            "Persistent reserve out",
+/* 60-67 */ NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+/* 68-6f */ NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+/* 70-77 */ NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+/* 78-7f */ NULL, NULL, NULL, NULL, NULL, NULL, "Extended CDB",
+	    "Variable length",
+/* 80-84 */ "Xdwrite(16)", "Rebuild(16)", "Regenerate(16)",
+	    "Third party copy out", "Third party copy in",
+/* 85-89 */ "ATA command pass through(16)", "Access control in",
+	    "Access control out", "Read(16)", "Compare and Write",
+/* 8a-8f */ "Write(16)", "ORWrite", "Read attributes", "Write attributes",
+            "Write and verify(16)", "Verify(16)",
+/* 90-94 */ "Pre-fetch(16)", "Synchronize cache(16)",
+            "Lock/unlock cache(16)", "Write same(16)", NULL,
+/* 95-99 */ NULL, NULL, NULL, NULL, NULL,
+/* 9a-9f */ NULL, NULL, NULL, "Service action bidirectional",
+	    "Service action in(16)", "Service action out(16)",
+/* a0-a5 */ "Report luns", "ATA command pass through(12)/Blank",
+            "Security protocol in", "Maintenance in", "Maintenance out",
+	    "Move medium/play audio(12)",
+/* a6-a9 */ "Exchange medium", "Move medium attached", "Read(12)",
+            "Play track relative(12)",
+/* aa-ae */ "Write(12)", NULL, "Erase(12), Get Performance",
+            "Read DVD structure", "Write and verify(12)",
+/* af-b1 */ "Verify(12)", "Search data high(12)", "Search data equal(12)",
+/* b2-b4 */ "Search data low(12)", "Set limits(12)",
+            "Read element status attached",
+/* b5-b6 */ "Security protocol out", "Send volume tag, set streaming",
+/* b7-b9 */ "Read defect data(12)", "Read element status", "Read CD msf",
+/* ba-bc */ "Redundancy group (in), Scan",
+            "Redundancy group (out), Set cd-rom speed", "Spare (in), Play cd",
+/* bd-bf */ "Spare (out), Mechanism status", "Volume set (in), Read cd",
+            "Volume set (out), Send DVD structure",
+};
+
+static const struct value_name_pair maint_in_arr[] = {
+	{0x5, "Report identifying information"},
+	{0xa, "Report target port groups"},
+	{0xb, "Report aliases"},
+	{0xc, "Report supported operation codes"},
+	{0xd, "Report supported task management functions"},
+	{0xe, "Report priority"},
+	{0xf, "Report timestamp"},
+	{0x10, "Management protocol in"},
+};
+#define MAINT_IN_SZ ARRAY_SIZE(maint_in_arr)
+
+static const struct value_name_pair maint_out_arr[] = {
+	{0x6, "Set identifying information"},
+	{0xa, "Set target port groups"},
+	{0xb, "Change aliases"},
+	{0xc, "Remove I_T nexus"},
+	{0xe, "Set priority"},
+	{0xf, "Set timestamp"},
+	{0x10, "Management protocol out"},
+};
+#define MAINT_OUT_SZ ARRAY_SIZE(maint_out_arr)
+
+static const struct value_name_pair serv_in12_arr[] = {
+	{0x1, "Read media serial number"},
+};
+#define SERV_IN12_SZ ARRAY_SIZE(serv_in12_arr)
+
+static const struct value_name_pair serv_out12_arr[] = {
+	{-1, "dummy entry"},
+};
+#define SERV_OUT12_SZ ARRAY_SIZE(serv_out12_arr)
+
+static const struct value_name_pair serv_bidi_arr[] = {
+	{-1, "dummy entry"},
+};
+#define SERV_BIDI_SZ ARRAY_SIZE(serv_bidi_arr)
+
+static const struct value_name_pair serv_in16_arr[] = {
+	{0x10, "Read capacity(16)"},
+	{0x11, "Read long(16)"},
+	{0x12, "Get LBA status"},
+	{0x13, "Report referrals"},
+};
+#define SERV_IN16_SZ ARRAY_SIZE(serv_in16_arr)
+
+static const struct value_name_pair serv_out16_arr[] = {
+	{0x11, "Write long(16)"},
+	{0x1f, "Notify data transfer device(16)"},
+};
+#define SERV_OUT16_SZ ARRAY_SIZE(serv_out16_arr)
+
+static const struct value_name_pair pr_in_arr[] = {
+	{0x0, "Persistent reserve in, read keys"},
+	{0x1, "Persistent reserve in, read reservation"},
+	{0x2, "Persistent reserve in, report capabilities"},
+	{0x3, "Persistent reserve in, read full status"},
+};
+#define PR_IN_SZ ARRAY_SIZE(pr_in_arr)
+
+static const struct value_name_pair pr_out_arr[] = {
+	{0x0, "Persistent reserve out, register"},
+	{0x1, "Persistent reserve out, reserve"},
+	{0x2, "Persistent reserve out, release"},
+	{0x3, "Persistent reserve out, clear"},
+	{0x4, "Persistent reserve out, preempt"},
+	{0x5, "Persistent reserve out, preempt and abort"},
+	{0x6, "Persistent reserve out, register and ignore existing key"},
+	{0x7, "Persistent reserve out, register and move"},
+};
+#define PR_OUT_SZ ARRAY_SIZE(pr_out_arr)
+
+/* SPC-4 rev 34 renamed the Extended Copy opcode to Third Party Copy Out.
+   LID1 (List Identifier length: 1 byte) is the Extended Copy found in SPC-2
+   and SPC-3 */
+static const struct value_name_pair tpc_out_arr[] = {
+	{0x0, "Extended copy(LID1)"},
+	{0x1, "Extended copy(LID4)"},
+	{0x10, "Populate token"},
+	{0x11, "Write using token"},
+	{0x1c, "Copy operation abort"},
+};
+#define TPC_OUT_SZ ARRAY_SIZE(tpc_out_arr)
+
+static const struct value_name_pair tpc_in_arr[] = {
+	{0x0, "Receive copy status(LID1)"},
+	{0x1, "Receive copy data(LID1)"},
+	{0x3, "Receive copy operating parameters"},
+	{0x4, "Receive copy failure details(LID1)"},
+	{0x5, "Receive copy status(LID4)"},
+	{0x6, "Receive copy data(LID4)"},
+	{0x7, "Receive ROD token information"},
+	{0x8, "Report all ROD tokens"},
+};
+#define TPC_IN_SZ ARRAY_SIZE(tpc_in_arr)
+
+
+static const struct value_name_pair variable_length_arr[] = {
+	{0x1, "Rebuild(32)"},
+	{0x2, "Regenerate(32)"},
+	{0x3, "Xdread(32)"},
+	{0x4, "Xdwrite(32)"},
+	{0x5, "Xdwrite extended(32)"},
+	{0x6, "Xpwrite(32)"},
+	{0x7, "Xdwriteread(32)"},
+	{0x8, "Xdwrite extended(64)"},
+	{0x9, "Read(32)"},
+	{0xa, "Verify(32)"},
+	{0xb, "Write(32)"},
+	{0xc, "Write an verify(32)"},
+	{0xd, "Write same(32)"},
+	{0x8801, "Format OSD"},
+	{0x8802, "Create (osd)"},
+	{0x8803, "List (osd)"},
+	{0x8805, "Read (osd)"},
+	{0x8806, "Write (osd)"},
+	{0x8807, "Append (osd)"},
+	{0x8808, "Flush (osd)"},
+	{0x880a, "Remove (osd)"},
+	{0x880b, "Create partition (osd)"},
+	{0x880c, "Remove partition (osd)"},
+	{0x880e, "Get attributes (osd)"},
+	{0x880f, "Set attributes (osd)"},
+	{0x8812, "Create and write (osd)"},
+	{0x8815, "Create collection (osd)"},
+	{0x8816, "Remove collection (osd)"},
+	{0x8817, "List collection (osd)"},
+	{0x8818, "Set key (osd)"},
+	{0x8819, "Set master key (osd)"},
+	{0x881a, "Flush collection (osd)"},
+	{0x881b, "Flush partition (osd)"},
+	{0x881c, "Flush OSD"},
+	{0x8f7e, "Perform SCSI command (osd)"},
+	{0x8f7f, "Perform task management function (osd)"},
+};
+#define VARIABLE_LENGTH_SZ ARRAY_SIZE(variable_length_arr)
+
+static struct sa_name_list sa_names_arr[] = {
+	{VARIABLE_LENGTH_CMD, variable_length_arr, VARIABLE_LENGTH_SZ},
+	{MAINTENANCE_IN, maint_in_arr, MAINT_IN_SZ},
+	{MAINTENANCE_OUT, maint_out_arr, MAINT_OUT_SZ},
+	{PERSISTENT_RESERVE_IN, pr_in_arr, PR_IN_SZ},
+	{PERSISTENT_RESERVE_OUT, pr_out_arr, PR_OUT_SZ},
+	{SERVICE_ACTION_IN_12, serv_in12_arr, SERV_IN12_SZ},
+	{SERVICE_ACTION_OUT_12, serv_out12_arr, SERV_OUT12_SZ},
+	{SERVICE_ACTION_BIDIRECTIONAL, serv_bidi_arr, SERV_BIDI_SZ},
+	{SERVICE_ACTION_IN_16, serv_in16_arr, SERV_IN16_SZ},
+	{SERVICE_ACTION_OUT_16, serv_out16_arr, SERV_OUT16_SZ},
+	{THIRD_PARTY_COPY_IN, tpc_in_arr, TPC_IN_SZ},
+	{THIRD_PARTY_COPY_OUT, tpc_out_arr, TPC_OUT_SZ},
+	{0, NULL, 0},
+};
+
+bool scsi_opcode_sa_name(int opcode, int service_action,
+			 const char **cdb_name, const char **sa_name)
+{
+	struct sa_name_list *sa_name_ptr;
+	const struct value_name_pair *arr = NULL;
+	int arr_sz, k;
+
+	*cdb_name = NULL;
+	if (opcode >= VENDOR_SPECIFIC_CDB)
+		return false;
+
+	if (opcode < ARRAY_SIZE(cdb_byte0_names))
+		*cdb_name = cdb_byte0_names[opcode];
+
+	for (sa_name_ptr = sa_names_arr; sa_name_ptr->arr; ++sa_name_ptr) {
+		if (sa_name_ptr->opcode == opcode) {
+			arr = sa_name_ptr->arr;
+			arr_sz = sa_name_ptr->arr_sz;
+			break;
+		}
+	}
+	if (!arr)
+		return false;
+
+	for (k = 0; k < arr_sz; ++k, ++arr) {
+		if (service_action == arr->value)
+			break;
+	}
+	if (k < arr_sz)
+		*sa_name = arr->name;
+
+	return true;
+}
+
+struct error_info {
+	unsigned short code12;	/* 0x0302 looks better than 0x03,0x02 */
+	unsigned short size;
+};
+
+/*
+ * There are 700+ entries in this table. To save space, we don't store
+ * (code, pointer) pairs, which would make sizeof(struct
+ * error_info)==16 on 64 bits. Rather, the second element just stores
+ * the size (including \0) of the corresponding string, and we use the
+ * sum of these to get the appropriate offset into additional_text
+ * defined below. This approach saves 12 bytes per entry.
+ */
+static const struct error_info additional[] =
+{
+#define SENSE_CODE(c, s) {c, sizeof(s)},
+#include "sense_codes.h"
+#undef SENSE_CODE
+};
+
+static const char *additional_text =
+#define SENSE_CODE(c, s) s "\0"
+#include "sense_codes.h"
+#undef SENSE_CODE
+	;
+
+struct error_info2 {
+	unsigned char code1, code2_min, code2_max;
+	const char * str;
+	const char * fmt;
+};
+
+static const struct error_info2 additional2[] =
+{
+	{0x40, 0x00, 0x7f, "Ram failure", ""},
+	{0x40, 0x80, 0xff, "Diagnostic failure on component", ""},
+	{0x41, 0x00, 0xff, "Data path failure", ""},
+	{0x42, 0x00, 0xff, "Power-on or self-test failure", ""},
+	{0x4D, 0x00, 0xff, "Tagged overlapped commands", "task tag "},
+	{0x70, 0x00, 0xff, "Decompression exception", "short algorithm id of "},
+	{0, 0, 0, NULL, NULL}
+};
+
+/* description of the sense key values */
+static const char * const snstext[] = {
+	"No Sense",	    /* 0: There is no sense information */
+	"Recovered Error",  /* 1: The last command completed successfully
+				  but used error correction */
+	"Not Ready",	    /* 2: The addressed target is not ready */
+	"Medium Error",	    /* 3: Data error detected on the medium */
+	"Hardware Error",   /* 4: Controller or device failure */
+	"Illegal Request",  /* 5: Error in request */
+	"Unit Attention",   /* 6: Removable medium was changed, or
+				  the target has been reset, or ... */
+	"Data Protect",	    /* 7: Access to the data is blocked */
+	"Blank Check",	    /* 8: Reached unexpected written or unwritten
+				  region of the medium */
+	"Vendor Specific(9)",
+	"Copy Aborted",	    /* A: COPY or COMPARE was aborted */
+	"Aborted Command",  /* B: The target aborted the command */
+	"Equal",	    /* C: A SEARCH DATA command found data equal,
+				  reserved in SPC-4 rev 36 */
+	"Volume Overflow",  /* D: Medium full with still data to be written */
+	"Miscompare",	    /* E: Source data and data on the medium
+				  do not agree */
+	"Completed",	    /* F: command completed sense data reported,
+				  may occur for successful command */
+};
+
+/* Get sense key string or NULL if not available */
+const char *
+scsi_sense_key_string(unsigned char key)
+{
+	if (key < ARRAY_SIZE(snstext))
+		return snstext[key];
+	return NULL;
+}
+EXPORT_SYMBOL(scsi_sense_key_string);
+
+/*
+ * Get additional sense code string or NULL if not available.
+ * This string may contain a "%x" and should be printed with ascq as arg.
+ */
+const char *
+scsi_extd_sense_format(unsigned char asc, unsigned char ascq, const char **fmt)
+{
+	int i;
+	unsigned short code = ((asc << 8) | ascq);
+	unsigned offset = 0;
+
+	*fmt = NULL;
+	for (i = 0; i < ARRAY_SIZE(additional); i++) {
+		if (additional[i].code12 == code)
+			return additional_text + offset;
+		offset += additional[i].size;
+	}
+	for (i = 0; additional2[i].fmt; i++) {
+		if (additional2[i].code1 == asc &&
+		    ascq >= additional2[i].code2_min &&
+		    ascq <= additional2[i].code2_max) {
+			*fmt = additional2[i].fmt;
+			return additional2[i].str;
+		}
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(scsi_extd_sense_format);
+
+static const char * const hostbyte_table[]={
+"DID_OK", "DID_NO_CONNECT", "DID_BUS_BUSY", "DID_TIME_OUT", "DID_BAD_TARGET",
+"DID_ABORT", "DID_PARITY", "DID_ERROR", "DID_RESET", "DID_BAD_INTR",
+"DID_PASSTHROUGH", "DID_SOFT_ERROR", "DID_IMM_RETRY", "DID_REQUEUE",
+"DID_TRANSPORT_DISRUPTED", "DID_TRANSPORT_FAILFAST", "DID_TARGET_FAILURE",
+"DID_NEXUS_FAILURE", "DID_ALLOC_FAILURE", "DID_MEDIUM_ERROR" };
+
+const char *scsi_hostbyte_string(int result)
+{
+	enum scsi_host_status hb = host_byte(result);
+	const char *hb_string = NULL;
+
+	if (hb < ARRAY_SIZE(hostbyte_table))
+		hb_string = hostbyte_table[hb];
+	return hb_string;
+}
+EXPORT_SYMBOL(scsi_hostbyte_string);
+
+#define scsi_mlreturn_name(result)	{ result, #result }
+static const struct value_name_pair scsi_mlreturn_arr[] = {
+	scsi_mlreturn_name(NEEDS_RETRY),
+	scsi_mlreturn_name(SUCCESS),
+	scsi_mlreturn_name(FAILED),
+	scsi_mlreturn_name(QUEUED),
+	scsi_mlreturn_name(SOFT_ERROR),
+	scsi_mlreturn_name(ADD_TO_MLQUEUE),
+	scsi_mlreturn_name(TIMEOUT_ERROR),
+	scsi_mlreturn_name(SCSI_RETURN_NOT_HANDLED),
+	scsi_mlreturn_name(FAST_IO_FAIL)
+};
+
+const char *scsi_mlreturn_string(int result)
+{
+	const struct value_name_pair *arr = scsi_mlreturn_arr;
+	int k;
+
+	for (k = 0; k < ARRAY_SIZE(scsi_mlreturn_arr); ++k, ++arr) {
+		if (result == arr->value)
+			return arr->name;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(scsi_mlreturn_string);