From: Avri Altman <avri.altman@wdc.com>
To: "James E . J . Bottomley" <jejb@linux.vnet.ibm.com>,
"Martin K . Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
Bart Van Assche <bvanassche@acm.org>,
Daejun Park <daejun7.park@samsung.com>,
Avri Altman <avri.altman@wdc.com>
Subject: [PATCH 2/4] scsi: ufshpb: Use a correct max multi chunk
Date: Sun, 8 Aug 2021 12:00:22 +0300 [thread overview]
Message-ID: <20210808090024.21721-3-avri.altman@wdc.com> (raw)
In-Reply-To: <20210808090024.21721-1-avri.altman@wdc.com>
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 let us consider the following scenario:
- SCSI_DEFAULT_MAX_SECTORS is 1024 limiting the IO chunks to 512KB
- The OEM changes scsi_host_template .max_sectors to be 2048, which
allows a 1M 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 cast transfer_len to u8: transfer_len = 0
- the command is failing with illegal request
Fixes: 41d8a9333cc9 (scsi: ufs: ufshpb: Add HPB 2.0 support)
Signed-off-by: Avri Altman <avri.altman@wdc.com>
---
drivers/scsi/ufs/ufshpb.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/scsi/ufs/ufshpb.h b/drivers/scsi/ufs/ufshpb.h
index c74a6c35a446..6df317dfe034 100644
--- a/drivers/scsi/ufs/ufshpb.h
+++ b/drivers/scsi/ufs/ufshpb.h
@@ -32,7 +32,7 @@
/* hpb support chunk size */
#define HPB_LEGACY_CHUNK_HIGH 1
#define HPB_MULTI_CHUNK_LOW 7
-#define HPB_MULTI_CHUNK_HIGH 256
+#define HPB_MULTI_CHUNK_HIGH 255
/* hpb vender defined opcode */
#define UFSHPB_READ 0xF8
--
2.17.1
next prev parent reply other threads:[~2021-08-08 9:01 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-08 9:00 [PATCH 0/4] scsi: ufs: Few HPB fixes Avri Altman
2021-08-08 9:00 ` [PATCH 1/4] scsi: ufshpb: re-wind the read timeout on every read Avri Altman
2021-08-08 9:00 ` Avri Altman [this message]
2021-08-08 9:00 ` [PATCH 3/4] scsi: ufshpb: Verify that num_inflight_map_req is non-negative Avri Altman
2021-08-08 9:00 ` [PATCH 4/4] scsi: ufshpb: Do not report victim error in HCM Avri Altman
2021-08-10 4:03 ` [PATCH 0/4] scsi: ufs: Few HPB fixes Martin K. Petersen
2021-08-17 3:17 ` Martin K. Petersen
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