In HPB2.0, if pre_req_min_tr_len < transfer_len < pre_req_max_tr_len, the
driver is expected to send a HPB-WRITE-BUFFER companion to HPB-READ.
The upper bound should fit into a single byte, regardless of bMAX_
DATA_SIZE_FOR_HPB_SINGLE_CMD which being an attribute (u32) can be
significantly larger.
To further illustrate the issue, consider the following scenario:
- SCSI_DEFAULT_MAX_SECTORS is 1024 limiting the I/O chunks to 512KB
- The OEM changes scsi_host_template .max_sectors to be 2048 which allows
for 1MB requests: transfer_len = 256
- pre_req_max_tr_len = HPB_MULTI_CHUNK_HIGH = 256
- ufshpb_is_supported_chunk() returns true (256 <= 256)
- WARN_ON_ONCE(256 > 256) doesn't warn
- ufshpb_set_hpb_read_to_upiu() casts transfer_len to u8: transfer_len = 0
- The command is failing with ILLEGAL REQUEST
Link: https://lore.kernel.org/r/20210808090024.21721-3-avri.altman@wdc.com
Fixes: 41d8a9333c (scsi: ufs: ufshpb: Add HPB 2.0 support)
Signed-off-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
07106f86ae