linux-kernel - [PATCH v2 07/26] ata: optimize struct ata_force

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Date:   Fri,  7 Feb 2020 15:27:15 +0100
From:   Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
To:     Jens Axboe <axboe@...nel.dk>
Cc:     Michael Schmitz <schmitzmic@...il.com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Christoph Hellwig <hch@....de>, linux-ide@...r.kernel.org,
        linux-m68k@...ts.linux-m68k.org, linux-kernel@...r.kernel.org,
        b.zolnierkie@...sung.com
Subject: [PATCH v2 07/26] ata: optimize struct ata_force_param size

Optimize struct ata_force_param size by:
- using u8 for cbl and spd_limit fields
- using u16 for lflags field

Code size savings on m68k arch using (modified) atari_defconfig:

   text    data     bss     dec     hex filename
before:
  41064     573      40   41677    a2cd drivers/ata/libata-core.o
after:
  40654     573      40   41267    a133 drivers/ata/libata-core.o

Reviewed-by: Christoph Hellwig <hch@....de>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
---
 drivers/ata/libata-core.c | 6 +++---
 include/linux/libata.h    | 1 +
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 9b824788d04f..47703c8ba0e6 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -90,12 +90,12 @@ atomic_t ata_print_id = ATOMIC_INIT(0);
 
 struct ata_force_param {
 	const char	*name;
-	unsigned int	cbl;
-	int		spd_limit;
+	u8		cbl;
+	u8		spd_limit;
 	unsigned long	xfer_mask;
 	unsigned int	horkage_on;
 	unsigned int	horkage_off;
-	unsigned int	lflags;
+	u16		lflags;
 };
 
 struct ata_force_ent {
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 86f4022c9b17..a3b14cafb2d5 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -176,6 +176,7 @@ enum {
 	ATA_DEV_NONE		= 11,	/* no device */
 
 	/* struct ata_link flags */
+	/* NOTE: struct ata_force_param currently stores lflags in u16 */
 	ATA_LFLAG_NO_HRST	= (1 << 1), /* avoid hardreset */
 	ATA_LFLAG_NO_SRST	= (1 << 2), /* avoid softreset */
 	ATA_LFLAG_ASSUME_ATA	= (1 << 3), /* assume ATA class */
-- 
2.24.1