Commit 3b64b188 authored Sep 24, 2012 by Yi Zou Committed by James Bottomley Oct 07, 2012

[SCSI] libfc: fix lun reset failure bugs in fc_fcp_resp handling of FCP_RSP_INFO

In LUN RESET testing involving NetApp targets, it is observed that LUN
RESET is failing. The fc_fcp_resp() is not completing the completion
for the LUN RESET task since fc_fcp_resp assumes that the FCP_RSP_INFO
is 8 bytes with the 4 byte reserved field, where in case of NetApp targets
the FCP_RSP to LUN RESET only has 4 bytes of FCP_RSP_INFO. This leads
fc_fcp_resp to error out w/o completing the task completion, eventually
causing LUN RESET to be escalated to host reset, which is not very nice.

Per FCP-3 r04, clause 9.5.15 and Table 23, the FCP_RSP_INFO field can be either
4 bytes or 8 bytes, with the last 4 bytes as "Reserved (if any)". Therefore it
is valid to have 4 bytes FCP_RSP_INFO like some of the NetApp targets behave.
Fixing this by validating the FCP_RSP_INFO against both the two spec allowed
length.

Reported-by: Frank Zhang <frank_1.zhang@intel.com>
Signed-off-by: Yi Zou <yi.zou@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

parent 31c37a6f

drivers/scsi/libfc/fc_fcp.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -851,7 +851,8 @@ static void fc_fcp_resp(struct fc_fcp_pkt fsp, struct fc_frame fp)
		fc_rp_info = (struct fcp_resp_rsp_info *)(rp_ex + 1);
		if (flags & FCP_RSP_LEN_VAL) {
		respl = ntohl(rp_ex->fr_rsp_len);
		if (respl != sizeof(*fc_rp_info))
		if ((respl != FCP_RESP_RSP_INFO_LEN4) &&
		(respl != FCP_RESP_RSP_INFO_LEN8))
		goto len_err;
		if (fsp->wait_for_comp) {
		/* Abuse cdb_status for rsp code */

include/scsi/fc/fc_fcp.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -127,6 +127,9 @@ struct fcp_txrdy {
		*
		* All response frames will always contain the fcp_resp template. Some
		* will also include the fcp_resp_len template.
		*
		* From Table 23, the FCP_RSP_INFO can either be 4 bytes or 8 bytes, both
		* are valid length.
		*/
		struct fcp_resp {
		__u8 _fr_resvd[8]; /* reserved */
		@@ -156,6 +159,9 @@ struct fcp_resp_rsp_info {
		__u8 _fr_resvd2[4]; /* reserved */
		};

		#define FCP_RESP_RSP_INFO_LEN4 4 /* without reserved field */
		#define FCP_RESP_RSP_INFO_LEN8 8 /* with reserved field */

		struct fcp_resp_with_ext {
		struct fcp_resp resp;
		struct fcp_resp_ext ext;

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