libata-scsi: better style in ata_msense_*()

`changeable` is the "version" of mode page requested by the user.
It will be less confusing/misleading if we do not check it
"together" with the setting bits of the drive.

Not to mention that we currently have ata_mselect_*() implemented
in a way that each of them will serve exclusively a particular bit
on each page. The old style will hence make the condition look even
more unnecessarily arcane if the ata_msense_*() is reflecting more
than one bit.

Signed-off-by: Tom Yan <tom.ty89@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 7d0e60b471cf673c4836cc4a8cdc1c4b6e3013ef..2bdb5dab922b734ae2daa80961ecd1fe36fab89a 100644 (file)
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2429,10 +2429,12 @@ static void modecpy(u8 *dest, const u8 *src, int n, bool changeable)
 static unsigned int ata_msense_caching(u16 *id, u8 *buf, bool changeable)
 {
        modecpy(buf, def_cache_mpage, sizeof(def_cache_mpage), changeable);
-       if (changeable || ata_id_wcache_enabled(id))
-               buf[2] |= (1 << 2);     /* write cache enable */
-       if (!changeable && !ata_id_rahead_enabled(id))
-               buf[12] |= (1 << 5);    /* disable read ahead */
+       if (changeable) {
+               buf[2] |= (1 << 2);     /* ata_mselect_caching() */
+       } else {
+               buf[2] |= (ata_id_wcache_enabled(id) << 2);     /* write cache enable */
+               buf[12] |= (!ata_id_rahead_enabled(id) << 5);   /* disable read ahead */
+       }
        return sizeof(def_cache_mpage);
 }
 
@@ -2451,8 +2453,13 @@ static unsigned int ata_msense_control(struct ata_device *dev, u8 *buf,
                                        bool changeable)
 {
        modecpy(buf, def_control_mpage, sizeof(def_control_mpage), changeable);
-       if (changeable || (dev->flags & ATA_DFLAG_D_SENSE))
-               buf[2] |= (1 << 2);     /* Descriptor sense requested */
+       if (changeable) {
+               buf[2] |= (1 << 2);     /* ata_mselect_control() */
+       } else {
+               bool d_sense = (dev->flags & ATA_DFLAG_D_SENSE);
+
+               buf[2] |= (d_sense << 2);       /* descriptor format sense data */
+       }
        return sizeof(def_control_mpage);
 }