libata-scsi: avoid repeated calculation of number of TRIM ranges

Currently libata statically allows only 1-block (512-byte) payload
for each TRIM command. Each payload can carry 64 TRIM ranges since
each range requires 8 bytes.

It is silly to keep doing the calculation (512 / 8) in different
places. Hence, define the new ATA_MAX_TRIM_RNUM for the result.

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

1 files changed, 3 insertions, 2 deletions

diff --git a/include/linux/ata.h b/include/linux/ata.h
index 2d6879392ae3..d20b1ee127b0 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -48,6 +48,7 @@ enum {
         ATA_MAX_SECTORS_1024    = 1024,
         ATA_MAX_SECTORS_LBA48   = 65535,/* TODO: 65536? */
         ATA_MAX_SECTORS_TAPE    = 65535,
+        ATA_MAX_TRIM_RNUM       = 64,   /* 512-byte payload / (6-byte LBA + 2-byte range per entry) */
 
         ATA_ID_WORDS            = 256,
         ATA_ID_CONFIG           = 0,
@@ -1069,12 +1070,12 @@ static inline void ata_id_to_hd_driveid(u16 *id)
  * TO NV CACHE PINNED SET.
  */
 static inline unsigned ata_set_lba_range_entries(void *_buffer,
-                unsigned buf_size, u64 sector, unsigned long count)
+                unsigned num, u64 sector, unsigned long count)
 {
         __le64 *buffer = _buffer;
         unsigned i = 0, used_bytes;
 
-        while (i < buf_size / 8 ) { /* 6-byte LBA + 2-byte range per entry */
+        while (i < num) {
                 u64 entry = sector |
                         ((u64)(count > 0xffff ? 0xffff : count) << 48);
                 buffer[i++] = __cpu_to_le64(entry);