diff options
Diffstat (limited to 'include/scsi/scsi.h')
| -rw-r--r-- | include/scsi/scsi.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h index 702fcfeb37f..0f55f5b2489 100644 --- a/include/scsi/scsi.h +++ b/include/scsi/scsi.h @@ -11,6 +11,25 @@ #include <linux/types.h> /* + * The maximum number of SG segments that we will put inside a + * scatterlist (unless chaining is used). Should ideally fit inside a + * single page, to avoid a higher order allocation. We could define this + * to SG_MAX_SINGLE_ALLOC to pack correctly at the highest order. The + * minimum value is 32 + */ +#define SCSI_MAX_SG_SEGMENTS 128 + +/* + * Like SCSI_MAX_SG_SEGMENTS, but for archs that have sg chaining. This limit + * is totally arbitrary, a setting of 2048 will get you at least 8mb ios. + */ +#ifdef ARCH_HAS_SG_CHAIN +#define SCSI_MAX_SG_CHAIN_SEGMENTS 2048 +#else +#define SCSI_MAX_SG_CHAIN_SEGMENTS SCSI_MAX_SG_SEGMENTS +#endif + +/* * SCSI command lengths */ |