ide-{floppy,tape}: remove request stack

* Add 'struct request request_sense_rq' to struct ide_{floppy,tape}_obj
  and switch ide*_retry_pc() to use it (there can be only one REQUEST SENSE
  request active for a given device).

* Remove no longer needed ide*_next_rq_storage(), rq_stack[]
  and rq_stack_index.

* DBG_PCRQ_STACK -> DBG_PC_STACK

* Update comments for IDE*_PC_STACK and idetape_queue_pc_{head,tail}().

There should be no functional changes caused by this patch.

Cc: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

2 files changed, 18 insertions, 72 deletions

diff --git a/drivers/ide/ide-floppy.c b/drivers/ide/ide-floppy.c
index 06db5edf9cee..41bb61037da2 100644
--- a/drivers/ide/ide-floppy.c
+++ b/drivers/ide/ide-floppy.c
@@ -77,8 +77,8 @@
 
 /*
  * In various places in the driver, we need to allocate storage for packet
- * commands and requests, which will remain valid while we leave the driver to
- * wait for an interrupt or a timeout event.
+ * commands, which will remain valid while we leave the driver to wait for
+ * an interrupt or a timeout event.
  */
 #define IDEFLOPPY_PC_STACK              (10 + IDEFLOPPY_MAX_PC_RETRIES)
 
@@ -108,9 +108,8 @@ typedef struct ide_floppy_obj {
         struct ide_atapi_pc pc_stack[IDEFLOPPY_PC_STACK];
         /* Next free packet command storage space */
         int pc_stack_index;
-        struct request rq_stack[IDEFLOPPY_PC_STACK];
-        /* We implement a circular array */
-        int rq_stack_index;
+
+        struct request request_sense_rq;
 
         /* Last error information */
         u8 sense_key, asc, ascq;
@@ -306,15 +305,6 @@ static struct ide_atapi_pc *idefloppy_next_pc_storage(ide_drive_t *drive)
         return (&floppy->pc_stack[floppy->pc_stack_index++]);
 }
 
-static struct request *idefloppy_next_rq_storage(ide_drive_t *drive)
-{
-        idefloppy_floppy_t *floppy = drive->driver_data;
-
-        if (floppy->rq_stack_index == IDEFLOPPY_PC_STACK)
-                floppy->rq_stack_index = 0;
-        return (&floppy->rq_stack[floppy->rq_stack_index++]);
-}
-
 static void ide_floppy_callback(ide_drive_t *drive)
 {
         idefloppy_floppy_t *floppy = drive->driver_data;
@@ -373,12 +363,12 @@ static void idefloppy_create_request_sense_cmd(struct ide_atapi_pc *pc)
  */
 static void idefloppy_retry_pc(ide_drive_t *drive)
 {
+        struct ide_floppy_obj *floppy = drive->driver_data;
+        struct request *rq = &floppy->request_sense_rq;
         struct ide_atapi_pc *pc;
-        struct request *rq;
 
         (void)ide_read_error(drive);
         pc = idefloppy_next_pc_storage(drive);
-        rq = idefloppy_next_rq_storage(drive);
         idefloppy_create_request_sense_cmd(pc);
         idefloppy_queue_pc_head(drive, pc, rq);
 }
diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index 83014abf330f..dd3533505e3b 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -56,8 +56,8 @@ enum {
         DBG_CHRDEV =            (1 << 2),
         /* all remaining procedures */
         DBG_PROCS =             (1 << 3),
-        /* buffer alloc info (pc_stack & rq_stack) */
-        DBG_PCRQ_STACK =        (1 << 4),
+        /* buffer alloc info (pc_stack) */
+        DBG_PC_STACK =  (1 << 4),
 };
 
 /* define to see debug info */
@@ -89,9 +89,9 @@ enum {
 #define IDETAPE_PC_BUFFER_SIZE          256
 
 /*
- *      In various places in the driver, we need to allocate storage
- *      for packet commands and requests, which will remain valid while
- *      we leave the driver to wait for an interrupt or a timeout event.
+ * In various places in the driver, we need to allocate storage for packet
+ * commands, which will remain valid while we leave the driver to wait for
+ * an interrupt or a timeout event.
  */
 #define IDETAPE_PC_STACK                (10 + IDETAPE_MAX_PC_RETRIES)
 
@@ -230,9 +230,8 @@ typedef struct ide_tape_obj {
         struct ide_atapi_pc pc_stack[IDETAPE_PC_STACK];
         /* Next free packet command storage space */
         int pc_stack_index;
-        struct request rq_stack[IDETAPE_PC_STACK];
-        /* We implement a circular array */
-        int rq_stack_index;
+
+        struct request request_sense_rq;
 
         /*
          * DSC polling variables.
@@ -462,7 +461,7 @@ static struct ide_atapi_pc *idetape_next_pc_storage(ide_drive_t *drive)
 {
         idetape_tape_t *tape = drive->driver_data;
 
-        debug_log(DBG_PCRQ_STACK, "pc_stack_index=%d\n", tape->pc_stack_index);
+        debug_log(DBG_PC_STACK, "pc_stack_index=%d\n", tape->pc_stack_index);
 
         if (tape->pc_stack_index == IDETAPE_PC_STACK)
                 tape->pc_stack_index = 0;
@@ -470,30 +469,6 @@ static struct ide_atapi_pc *idetape_next_pc_storage(ide_drive_t *drive)
 }
 
 /*
- *      idetape_next_rq_storage is used along with idetape_next_pc_storage.
- *      Since we queue packet commands in the request queue, we need to
- *      allocate a request, along with the allocation of a packet command.
- */
-
-/**************************************************************
- *                                                            *
- *  This should get fixed to use kmalloc(.., GFP_ATOMIC)      *
- *  followed later on by kfree().   -ml                       *
- *                                                            *
- **************************************************************/
-
-static struct request *idetape_next_rq_storage(ide_drive_t *drive)
-{
-        idetape_tape_t *tape = drive->driver_data;
-
-        debug_log(DBG_PCRQ_STACK, "rq_stack_index=%d\n", tape->rq_stack_index);
-
-        if (tape->rq_stack_index == IDETAPE_PC_STACK)
-                tape->rq_stack_index = 0;
-        return (&tape->rq_stack[tape->rq_stack_index++]);
-}
-
-/*
  * called on each failed packet command retry to analyze the request sense. We
  * currently do not utilize this information.
  */
@@ -692,17 +667,7 @@ static void idetape_create_request_sense_cmd(struct ide_atapi_pc *pc)
 /*
  * Generate a new packet command request in front of the request queue, before
  * the current request, so that it will be processed immediately, on the next
- * pass through the driver. The function below is called from the request
- * handling part of the driver (the "bottom" part). Safe storage for the request
- * should be allocated with ide_tape_next_{pc,rq}_storage() prior to that.
- *
- * Memory for those requests is pre-allocated at initialization time, and is
- * limited to IDETAPE_PC_STACK requests. We assume that we have enough space for
- * the maximum possible number of inter-dependent packet commands.
- *
- * The higher level of the driver - The ioctl handler and the character device
- * handling functions should queue request to the lower level part and wait for
- * their completion using idetape_queue_pc_tail or idetape_queue_rw_tail.
+ * pass through the driver.
  */
 static void idetape_queue_pc_head(ide_drive_t *drive, struct ide_atapi_pc *pc,
                                   struct request *rq)
@@ -726,12 +691,12 @@ static void idetape_queue_pc_head(ide_drive_t *drive, struct ide_atapi_pc *pc,
  */
 static void idetape_retry_pc(ide_drive_t *drive)
 {
+        struct ide_tape_obj *tape = drive->driver_data;
+        struct request *rq = &tape->request_sense_rq;
         struct ide_atapi_pc *pc;
-        struct request *rq;
 
         (void)ide_read_error(drive);
         pc = idetape_next_pc_storage(drive);
-        rq = idetape_next_rq_storage(drive);
         idetape_create_request_sense_cmd(pc);
         set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
         idetape_queue_pc_head(drive, pc, rq);
@@ -1247,16 +1212,7 @@ static void idetape_create_test_unit_ready_cmd(struct ide_atapi_pc *pc)
 
 /*
  * We add a special packet command request to the tail of the request queue, and
- * wait for it to be serviced. This is not to be called from within the request
- * handling part of the driver! We allocate here data on the stack and it is
- * valid until the request is finished. This is not the case for the bottom part
- * of the driver, where we are always leaving the functions to wait for an
- * interrupt or a timer event.
- *
- * From the bottom part of the driver, we should allocate safe memory using
- * idetape_next_pc_storage() and ide_tape_next_rq_storage(), and add the request
- * to the request list without waiting for it to be serviced! In that case, we
- * usually use idetape_queue_pc_head().
+ * wait for it to be serviced.
  */
 static int idetape_queue_pc_tail(ide_drive_t *drive, struct ide_atapi_pc *pc)
 {