ide-floppy: allocate only toplevel packet commands

This makes the top-level function just allocate a single pc entry, and then
pass it down as a pointer to all the helper functions that also need one
of those "struct ide_atapi_pc" things. As far as I can tell, the use of
these things never overlaps each other, BUT I DID NOT CHECK VERY CLOSELY!

So I'm not guaranteeing this is correct, and I don't have the hardware. It
would be good for somebody who knows the code more, and has the hardware,
could please test this?

With this, ide-floppy still has fairly big stack usage, but instead of

	idefloppy_ioctl [vmlinux]:              1208
	ide_floppy_get_capacity [vmlinux]:      872
	idefloppy_release [vmlinux]:            408
	idefloppy_open [vmlinux]:               408

where those two first ones are at the very top of the list of stack users
for me, it's now

	ide_floppy_get_capacity [vmlinux]:           404
	ide_floppy_ioctl [vmlinux]:                  364

ie they are still high, but they are no longer at the top.

Borislav: Since ide_floppy_get_capacity is passed as a function pointer to other
parts of the kernel (e.g., block layer) we need that ide_atapi_pc to be created
on stack. Also, redid stack users numbers above. The two functions missing from
Linus' original 'make stackusage' output are due to ide being
rewritten/reorganized atm.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 13 insertions, 13 deletions

diff --git a/drivers/ide/ide-floppy.c b/drivers/ide/ide-floppy.c
index aeb1ad782f54..1f07f3818938 100644
--- a/drivers/ide/ide-floppy.c
+++ b/drivers/ide/ide-floppy.c
@@ -342,38 +342,38 @@ static ide_startstop_t ide_floppy_do_request(ide_drive_t *drive,
  * Look at the flexible disk page parameters. We ignore the CHS capacity
  * parameters and use the LBA parameters instead.
  */
-static int ide_floppy_get_flexible_disk_page(ide_drive_t *drive)
+static int ide_floppy_get_flexible_disk_page(ide_drive_t *drive,
+					     struct ide_atapi_pc *pc)
 {
 	struct ide_disk_obj *floppy = drive->driver_data;
 	struct gendisk *disk = floppy->disk;
-	struct ide_atapi_pc pc;
 	u8 *page;
 	int capacity, lba_capacity;
 	u16 transfer_rate, sector_size, cyls, rpm;
 	u8 heads, sectors;
 
-	ide_floppy_create_mode_sense_cmd(&pc, IDEFLOPPY_FLEXIBLE_DISK_PAGE);
+	ide_floppy_create_mode_sense_cmd(pc, IDEFLOPPY_FLEXIBLE_DISK_PAGE);
 
-	if (ide_queue_pc_tail(drive, disk, &pc)) {
+	if (ide_queue_pc_tail(drive, disk, pc)) {
 		printk(KERN_ERR PFX "Can't get flexible disk page params\n");
 		return 1;
 	}
 
-	if (pc.buf[3] & 0x80)
+	if (pc->buf[3] & 0x80)
 		drive->dev_flags |= IDE_DFLAG_WP;
 	else
 		drive->dev_flags &= ~IDE_DFLAG_WP;
 
 	set_disk_ro(disk, !!(drive->dev_flags & IDE_DFLAG_WP));
 
-	page = &pc.buf[8];
+	page = &pc->buf[8];
 
-	transfer_rate = be16_to_cpup((__be16 *)&pc.buf[8 + 2]);
-	sector_size   = be16_to_cpup((__be16 *)&pc.buf[8 + 6]);
-	cyls          = be16_to_cpup((__be16 *)&pc.buf[8 + 8]);
-	rpm           = be16_to_cpup((__be16 *)&pc.buf[8 + 28]);
-	heads         = pc.buf[8 + 4];
-	sectors       = pc.buf[8 + 5];
+	transfer_rate = be16_to_cpup((__be16 *)&pc->buf[8 + 2]);
+	sector_size   = be16_to_cpup((__be16 *)&pc->buf[8 + 6]);
+	cyls          = be16_to_cpup((__be16 *)&pc->buf[8 + 8]);
+	rpm           = be16_to_cpup((__be16 *)&pc->buf[8 + 28]);
+	heads         = pc->buf[8 + 4];
+	sectors       = pc->buf[8 + 5];
 
 	capacity = cyls * heads * sectors * sector_size;
 
@@ -499,7 +499,7 @@ static int ide_floppy_get_capacity(ide_drive_t *drive)
 
 	/* Clik! disk does not support get_flexible_disk_page */
 	if (!(drive->atapi_flags & IDE_AFLAG_CLIK_DRIVE))
-		(void) ide_floppy_get_flexible_disk_page(drive);
+		(void) ide_floppy_get_flexible_disk_page(drive, &pc);
 
 	return rc;
 }