[ewg] [PATCH for OFED-3.5] ib_srp: Backport to older kernels

[Bart Van Assche]

This patch has been tested on RHEL 6.0, RHEL 6.1, RHEL 6.2, RHEL 6.3
and Ubuntu 10.04.

Signed-off-by: Bart Van Assche <bvanassche at acm.org>
---
 drivers/infiniband/ulp/srp/ib_srp.c |  111 ++++++++++++++++++++++++++++++++++-
 1 files changed, 108 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 1b5b0c7..523fe57 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -32,6 +32,10 @@
 
 #define pr_fmt(fmt) PFX fmt
 
+#define DRV_NAME	"ib_srp"
+#define PFX		DRV_NAME ": "
+
+#include <linux/version.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/slab.h>
@@ -41,7 +45,11 @@
 #include <linux/random.h>
 #include <linux/jiffies.h>
 
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 37)
 #include <linux/atomic.h>
+#else
+#include <asm/atomic.h>
+#endif
 
 #include <scsi/scsi.h>
 #include <scsi/scsi_device.h>
@@ -51,11 +59,54 @@
 
 #include "ib_srp.h"
 
-#define DRV_NAME	"ib_srp"
-#define PFX		DRV_NAME ": "
 #define DRV_VERSION	"0.2"
 #define DRV_RELDATE	"November 1, 2005"
 
+#ifndef pr_warn
+#define pr_warn pr_warning
+#endif
+
+#if !defined(RHEL_MAJOR) && LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 37) || \
+	RHEL_MAJOR -0 < 6 || RHEL_MAJOR -0 == 6 && RHEL_MINOR -0 == 0
+struct srp_cred_req {
+	u8	opcode;
+	u8	sol_not;
+	u8	reserved[2];
+	__be32	req_lim_delta;
+	u64	tag;
+};
+
+struct srp_cred_rsp {
+	u8	opcode;
+	u8	reserved[7];
+	u64	tag;
+};
+
+/*
+ * The SRP spec defines the fixed portion of the AER_REQ structure to be
+ * 36 bytes, so it needs to be packed to avoid having it padded to 40 bytes
+ * on 64-bit architectures.
+ */
+struct srp_aer_req {
+	u8	opcode;
+	u8	sol_not;
+	u8	reserved[2];
+	__be32	req_lim_delta;
+	u64	tag;
+	u32	reserved2;
+	__be64	lun;
+	__be32	sense_data_len;
+	u32	reserved3;
+	u8	sense_data[0];
+} __attribute__((packed));
+
+struct srp_aer_rsp {
+	u8	opcode;
+	u8	reserved[7];
+	u64	tag;
+};
+#endif
+
 MODULE_AUTHOR("Roland Dreier");
 MODULE_DESCRIPTION("InfiniBand SCSI RDMA Protocol initiator "
 		   "v" DRV_VERSION " (" DRV_RELDATE ")");
@@ -713,7 +764,11 @@ err:
 	if (target->state == SRP_TARGET_CONNECTING) {
 		target->state = SRP_TARGET_DEAD;
 		INIT_WORK(&target->work, srp_remove_work);
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 36)
 		queue_work(ib_wq, &target->work);
+#else
+		schedule_work(&target->work);
+#endif
 	}
 	spin_unlock_irq(&target->lock);
 
@@ -1301,7 +1356,50 @@ static void srp_send_completion(struct ib_cq *cq, void *target_ptr)
 	}
 }
 
-static int srp_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *scmnd)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 36)
+/*
+ * Kernel with host lock push-down patch. See also upstream commit
+ * f281233d3eba15fb225d21ae2e228fd4553d824a.
+ */
+#define SRP_QUEUECOMMAND srp_queuecommand
+#elif defined(RHEL_MAJOR) && RHEL_MAJOR -0 == 6 && RHEL_MINOR -0 >= 2
+/*
+ * Kernel with lockless SCSI command dispatching enabled.
+ * See also the RHEL 6.2 release notes (http://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/6/html-single/6.2_Release_Notes/index.html).
+ */
+static int srp_queuecommand_wrk(struct Scsi_Host *shost,
+				struct scsi_cmnd *scmnd);
+static int srp_queuecommand(struct scsi_cmnd *scmnd,
+			    void (*done)(struct scsi_cmnd *))
+{
+	scmnd->scsi_done = done;
+	return srp_queuecommand_wrk(scmnd->device->host, scmnd);
+}
+#define SRP_QUEUECOMMAND srp_queuecommand_wrk
+#else
+/*
+ * Kernel that invokes srp_queuecommand with the SCSI host lock held.
+ */
+static int srp_queuecommand_wrk(struct Scsi_Host *shost,
+				struct scsi_cmnd *scmnd);
+static int srp_queuecommand(struct scsi_cmnd *scmnd,
+			    void (*done)(struct scsi_cmnd *))
+{
+	struct Scsi_Host *shost = scmnd->device->host;
+	int res;
+
+	spin_unlock_irq(shost->host_lock);
+
+	scmnd->scsi_done = done;
+	res = srp_queuecommand_wrk(shost, scmnd);
+
+	spin_lock_irq(shost->host_lock);
+	return res;
+}
+#define SRP_QUEUECOMMAND srp_queuecommand_wrk
+#endif
+
+static int SRP_QUEUECOMMAND(struct Scsi_Host *shost, struct scsi_cmnd *scmnd)
 {
 	struct srp_target_port *target = host_to_target(shost);
 	struct srp_request *req;
@@ -1861,6 +1959,9 @@ static struct scsi_host_template srp_template = {
 	.name				= "InfiniBand SRP initiator",
 	.proc_name			= DRV_NAME,
 	.info				= srp_target_info,
+#if defined(RHEL_MAJOR) && RHEL_MAJOR -0 == 6 && RHEL_MINOR -0 >= 2
+	.lockless			= true,
+#endif
 	.queuecommand			= srp_queuecommand,
 	.eh_abort_handler		= srp_abort,
 	.eh_device_reset_handler	= srp_reset_device,
@@ -2451,7 +2552,11 @@ static void srp_remove_one(struct ib_device *device)
 		 * started before we marked our target ports as
 		 * removed, and any target port removal tasks.
 		 */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 36)
 		flush_workqueue(ib_wq);
+#else
+		flush_scheduled_work();
+#endif
 
 		list_for_each_entry_safe(target, tmp_target,
 					 &host->target_list, list) {
-- 
1.7.7