ata: libata-core: fix sloppy typing in ata_id_n_sectors()

The code multiplying the # of cylinders/heads/sectors in ata_id_n_sectors()
to get a disk capacity implicitly uses the *int* type for that calculation
and casting the result to 'u64' before returning ensues a sign extension.
Explicitly casting the 'u16' typed multipliers to 'u32' results in avoiding
a sign extension instruction and so in a more compact code...

Found by Linux Verification Center (linuxtesting.org) with the SVACE static
analysis tool.

Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 9601fa92950a061c5b9599799c57360da1f5450d..e3f1c3da59503e9aed60216d08363790ea449572 100644 (file)
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1107,11 +1107,13 @@ static u64 ata_id_n_sectors(const u16 *id)
                        return ata_id_u32(id, ATA_ID_LBA_CAPACITY);
        } else {
                if (ata_id_current_chs_valid(id))
-                       return id[ATA_ID_CUR_CYLS] * id[ATA_ID_CUR_HEADS] *
-                              id[ATA_ID_CUR_SECTORS];
+                       return (u32)id[ATA_ID_CUR_CYLS] *
+                              (u32)id[ATA_ID_CUR_HEADS] *
+                              (u32)id[ATA_ID_CUR_SECTORS];
                else
-                       return id[ATA_ID_CYLS] * id[ATA_ID_HEADS] *
-                              id[ATA_ID_SECTORS];
+                       return (u32)id[ATA_ID_CYLS] *
+                              (u32)id[ATA_ID_HEADS] *
+                              (u32)id[ATA_ID_SECTORS];
        }
 }